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Title: Paint Technology and Tests
Author: Gardner, Henry A.
Language: English
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  PAINT TECHNOLOGY AND TESTS


  Published by the
  McGraw-Hill Book Company
  New York


  Successors to the Book Departments of the

  McGraw Publishing Company                      Hill Publishing Company


  Publishers of Books for

  Electrical World                    The Engineering and Mining Journal
  Engineering Record                                  American Machinist
  Electric Railway Journal                                      Coal Age
  Metallurgical and Chemical Engineering                           Power



  PAINT TECHNOLOGY
  AND TESTS.

  BY

  HENRY A. GARDNER

  _Assistant Director, The Institute of Industrial Research,
  Washington, D. C._

  _Director, Scientific Section, Paint Manufacturers' Association
  of the United States, etc._

  McGRAW-HILL BOOK COMPANY
  239 WEST 39TH STREET, NEW YORK
  6 BOUVERIE STREET, LONDON, E.C.
  1911



  _Copyright, 1911, by the_ MCGRAW-HILL BOOK COMPANY

  THE·PLIMPTON·PRESS·NORWOOD·MASS·U·S·A



  TO
  MY MOTHER



PREFACE


A few years ago the producer and consumer of paints possessed
comparatively little knowledge of the relative durability of various
pigments and oils. There existed in some cases a prejudice for a few
standard products, that often held the user in bondage, discouraging
investigation and exciting suspicion whenever discoveries were made,
that brought forth new materials. Such conditions indicated to the more
progressive, the need of positive information regarding the value of
various painting materials, and the advisability of having the questions
at issue determined in a practical manner.

The desire that such work should be instituted, resulted in the creation
of a Scientific Section, the scope of which was to make investigations
to determine the relative merits of different types of paint, and to
enlighten the industry on various technical problems. Paint exposure
tests of an extensive nature were started in various sections of the
country where climatic conditions vary. This field work was supplemented
in the laboratory by a series of important researches into the
properties of pigments, oils, and other raw products entering into the
manufacture of protective coatings. The results of the work were
published in bulletin form and given wide distribution. The demand for
these bulletins early exhausted the original impress, and a general
summary therefore forms a part of this volume.

The purpose of the book is primarily to serve as a reference work for
grinders, painters, engineers, and students; matter of an important
nature to each being presented. Without repetition of the matter found
in other books, two chapters on raw products have been included, and
they present in condensed form a summary of information that will prove
of aid to one who desires to become conversant with painting materials
with a view to continuing tests such as are outlined herein. In other
chapters there has been compiled considerable matter from lectures and
technical articles presented by the writer before various colleges,
engineering societies, and painters' associations.

The writer wishes to gratefully acknowledge the untiring efforts of the
members of the Educational Bureau of the Paint Manufacturers'
Association, whose early endeavors made possible many of the tests
described in this volume. Kind acknowledgment is also made to members of
the International Association of Master House Painters and Decorators of
the United States and Canada, who stood always ready to aid in
investigations which promised to bring new light into their art and
craft.

HENRY A. GARDNER.

WASHINGTON, October, 1911.



CONTENTS


  CHAPTER                                                  PAGE

     I PAINT OILS AND THINNERS                                1

    II A STUDY OF DRIERS AND THEIR EFFECT                    21

   III PAINT PIGMENTS AND THEIR PROPERTIES                   42

    IV PHYSICAL LABORATORY PAINT TESTS                       70

     V THE THEORY AND PRACTICE OF SCIENTIFIC PAINT MAKING    93

    VI THE SCOPE OF PRACTICAL PAINT TESTS                   105

   VII CONDITIONS NOTED AT INSPECTION OF TESTS              114

  VIII RESULTS OF ATLANTIC CITY TESTS                       124

    IX RESULTS OF PITTSBURG TESTS                           135

     X A LABORATORY STUDY OF TEST PANELS                    149

    XI ADDITIONAL TESTS AT ATLANTIC CITY AND PITTSBURG      174

   XII NORTH DAKOTA PAINT TESTS                             182

  XIII TENNESSEE PAINT TESTS                                201

   XIV WASHINGTON PAINT TESTS                               207

    XV CEMENT AND CONCRETE PAINT TESTS                      214

   XVI STRUCTURAL STEEL PAINT TESTS                         220

  XVII THE SANITARY VALUE OF WALL PAINTS                    252



PAINT TECHNOLOGY



CHAPTER I

PAINT OILS AND THINNERS


=Constants and Characteristics of Oils and Their Effect upon Drying.= An
attempt has been made to give in this chapter a brief summary of the
most important characteristics of those oils finding application in the
paint and varnish industry. For methods of oil analysis, the reader is
referred to standard works on this subject; the analytical constants
herein being given only for comparative purposes.

It is well known that one of the most desirable features of a paint oil
is the ability to set up in a short period to a hard surface that will
not take dust. This drying property is dependent upon the chemical
nature of the oil. If it is an unsaturated compound, like linseed oil,
rapid absorption of oxygen will cause the film to dry rapidly and become
hard. If the oil be of a fully satisfied nature, like mineral oil,
oxygen cannot be taken up to any great extent and drying will not take
place. The various animal and vegetable oils differ in their power of
oxygen absorption to a lesser or greater extent. This difference is
referred to by the chemist in terms of the iodine value. The iodine
value of linseed oil is approximately 190, meaning that one gram of the
oil will take up 190 centigrams of iodine. Oils with high iodine values
have good drying powers, while those with low iodine values are, as a
rule, very slow drying in nature.

For a description of the working and drying properties of various oils
used in paints, see Chapter XIV. The oxygen absorption of various oils
and mixtures is shown in Chapter II.

=Linseed Oil.= The seed of the flax plant which is extensively grown in
North Dakota, Argentine Republic and Russia, contains approximately 36%
of oil which may be obtained by grinding, heating, and expression. Ripe
native seed generally produces a pale oil of little odor; the oil from
Argentine seed often having a greenish tint and an odor resembling
sorghum. While filtering, pressing and ageing will remove considerable
of the ("foots") mucilaginous matter, phosphates, silica, etc., from the
oil, the better grades which are intended for varnish making are often
refined with sulphuric acid. A light colored oil which may be heated
without "breaking" results from this treatment, but such oils are apt to
contain considerable free fatty acid, unless they are washed with alkali
subsequent to the sulphuric acid treatment. On account of its rapid
drying properties and general adaptability for all classes of paints and
varnishes, linseed oil has never been supplanted by any other oil.
Chemically it consists of the glycerides of linoleic, oleic, and
isolinoleic acid, its constitution being responsible for its very high
iodine value.

[Illustration: Field of Flax in bloom in North Dakota]

Boiled linseed oil, a heavier and darker product, is made by heating the
raw oil in open kettles to high temperatures, generally with the
addition of metallic driers such as litharge, and black manganese. The
resinates of lead and manganese are often added to oil heated at a lower
temperature, to obtain a boiled oil of lighter color.

[Illustration: New type of Flax Harvester which pulls plant up by the
roots, thus preventing infection of soil]

[Illustration: Modern Concrete Elevators for storing Flaxseed]

[Illustration: View of Linseed Oil Factory showing hydraulic press,
tanks, etc.]

[Illustration: _Photographs courtesy of Spencer Kellogg Sons_

Flaxseed Crushers]

[Illustration: Filter Presses for removing extraneous matter from
linseed oil]

[Illustration: Linseed Cake from Oil Press]

[Illustration: Glycine Hispida

Mammoth soya bean plants]

[Illustration: _Photographs courtesy of David Fairchild, Plant Explorer,
U. S. Dept. of Agriculture_

Glycine Hispida

Soya bean plants under cultivation at Arlington, Va.]

By blowing air through linseed oil that has been heated to approximately
200 degrees Fahrenheit, either with or without drier, heavy bodied oils
are obtained, which find special application in varnishes and technical
paints. As the viscosity of these oils increase, the iodine values
decrease, and a slight rise in saponification value and specific gravity
is observed. The following analyses of various types of linseed oil were
recently made by the writer:

  ===========+========+========+=========+========+=========+=========
             |Pure Raw| Boiled | Boiled  | Blown  |  Litho. |  Old
             |Linseed |  L. O. |  L. O.  | L. O.  |  L. O.  |Treated
             |  Oil   | (Lino- | (Resin- |        |         |  Oil
             |        | leate) |  ate)   |        |         |
  -----------+--------+--------+---------+--------+---------+---------
  Color      | Amber  |  Dark  | Reddish |  Pale  |  Dark   |  Amber
             | Clear  | Brown  |  Brown  |        |  Brown  |  Clear
             |        |        |         |        |         |
  Sp. Gr. at |   .933 |  .941  |   .930  |  .968  |  .970   |  .943
  15° C.     |        |        |         |        |         |
             |Average |        |         |        |         |
  Iodine No. |   180  |  172   |   176   |   133  |   102   |   172
             |        |        |         |        |         |
  Saponifi-  |   191  |  187   |   186   |   189  |   199   |   197
  cation No. |        |        |         |        |         |
             |        |        |         |        |         |
  Free Fatty |   3.2  |  2.7   |   2.2   |   2.8  |   2.7   |   6.9
  Acid       |        |        |         |        |         |
             |        |        |         |        |         |
  Unsaponi-  |   1.4  |   --   |    --   |    --  |    --   |   1.8
  fiable     |        |        |         |        |         |
             |        |        |         |        |         |
  Maumene    |   111  |   --   |    --   |    --  |    --   |   96
             |        |        |         |        |         |
  Moisture   |   .2%  |   --   |    --   |    --  |    --   |  none
  ===========+========+========+=========+========+=========+=========

[Illustration: Glycine Hispida

Mammoth soya bean plant]

[Illustration: Glycine Hispida

Soya bean plant, showing nitrogen gathering tubercles on roots]

=Soya Bean Oil.= The soya plant which is extensively cultivated in Asia
produces a seed bearing up to 22% and over of a golden colored oil
having a peculiar leguminous odor. The oil, which probably consists of
the glycerides of oleic, linoleic, and palmitic acids, is secured by
crushing, steaming and pressing the seed. There are several varieties of
the plant, and they are said to be the best annual legume for forage,
the straw and fruit being rich in nitrogen and very fattening as a
cattle food. Soya may be grown in nearly any country and is a great
carrier of nitrogen to land deficient in this element. Although the oil
has been used abroad for many years for soap-making purposes, its use as
a drying oil is comparatively recent; being introduced into the paint
industry of the United States during the year 1909, when linseed oil
started on its phenomenal rise in price.

The oil has given fair service in some paints when mixed with upwards of
75% of pure linseed oil. It is of a semi-drying nature, but may be made
to dry rapidly when mixed with manganese and lead linoleate driers. By
compounding it under heat with tung oil and rosin, a substitute for
linseed oil is produced, which some claim to be quite valuable.

     Table I gives the constants of several samples of soya oil
     examined by the writer. Table II shows the iodine value of
     mixtures of soya and linseed oils. Table III shows the results of
     drying experiments on soya oils containing different percentages
     of lead and manganese driers.

TABLE I

CHEMICAL CHARACTERISTICS OF SOYA BEAN OIL

  =======+==========+===========+============+==========+===========
  Sample | Specific | Acid No.  |  Saponifi- | Iodine   |Per cent.
    No.  | gravity  |           |   cation   |   No.    | of foots
         |          |           |    No.     |          |
  -------+----------+-----------+------------+----------+-----------
    1    |  0.9233  |   1.87    |   188.4    |  127.8   |    3.81
    2    |  0.9240  |   1.92    |   188.3    |  127.2   |     --
    3    |  0.9231  |   1.90    |   187.8    |  131.7   |     --
    4    |  0.9233  |   1.91    |   188.4    |  129.8   |     --
    5    |    --    |    --     |     --     |  130.0   |     --
    6    |    --    |    --     |     --     |  132.6   |     --
    7    |    --    |    --     |     --     |  136.0   |     --
  Average|  0.9234  |   1.90    |   188.2    |  130.7   |     --
  =======+==========+===========+============+==========+===========

TABLE II

IODINE VALUES OF LINSEED OIL AND MIXED OILS

  ==============+============+============+============+============
                |            |    Soya    |    Soya    |    Soya
    Sample No.  |  Straight  |25 per cent.|50 per cent.|75 per cent.
                |  linseed   |  Linseed   |  Linseed   |  Linseed
                |            |75 per cent.|50 per cent.|25 per cent.
  --------------+------------+------------+------------+------------
        1       |   190.3    |   175.2    |   160.7    |   140.4
        2       |   189.5    |   175.9    |   161.7    |   140.8
        3       |   188.0    |   175.4    |   160.3    |   139.0
  --------------+------------+------------+------------+------------
     Average    |   189.3    |   175.5    |   160.9    |   140.4
  ==============+============+============+============+============

TABLE III

SOYA BEAN OIL AND LEAD DRIER

  =========+==========+====+====+====+====+====+====+====+====
  Per cent.|          |    |    |    |    |    |    |    |
    PbO    |          |0.05|0.10|0.30|0.50|0.70|1.00|1.30|1.60
  ---------+----------+----+----+----+----+----+----+----+----
           | {  1 day | -- |0.07|0.63|1.34|1.05|1.53|0.93|1.35
           | {  3 days| -- |0.07|3.52|4.31|2.75|4.86|4.82|4.12
  Per ct.  | {  5 days| -- |0.09|5.04|6.06|6.09|6.75|6.66|5.52
  gain     | { 12 days| -- | -- |6.88|7.54|7.43|7.76|7.32|6.47
           | { 15 days| -- | -- |8.84|8.93|8.59|8.81|8.44|7.46
           | { 20 days|0.05|0.20|9.02|9.08|8.90|9.03|8.65|7.83
  ---------+----------+----+----+----+----+----+----+----+----

SOYA BEAN OIL AND MANGANESE DRIER

  -----------------+----------+----+----+----+----+----
  Per cent. MnO_{2}|          |0.01|0.05|0.15|0.26|0.30
  -----------------+----------+----+----+----+----+----
                   | {  1 day | -- | -- |0.02|0.02|0.01
    Per ct. gain   | { 10 days| -- |5.06|6.48|6.10|5.97
                   | { 20 days|0.05|9.07|8.80|6.78|6.51
  -----------------+----------+----+----+----+----+----

SOYA BEAN OIL, MANGANESE AND LEAD DRIER

  -------------+----------+----+----+----
  Per cent. PbO|          |0.20|0.30|0.50
  -------------+----------+----+----+----
  MnO_{2}      |          |0.05|0.15|0.25
  -------------+----------+----+----+----
               | {  1 day |3.04|3.77|3.74
  Per ct. gain | {  8 days|5.96|6.43|6.47
               | { 12 days|6.33|6.78|6.67
  =============+==========+====+====+====

=Tung Oil.= There are grown in China and Japan many varieties of the
"aleurites cordata," popularly known as the tung tree. This tree bears
great quantities of large sized nuts containing as high as 40% of an oil
which yields itself in a viscous yellow form upon heating and crushing
of the fruit. The raw oil, which chemically consists of the glycerides
of oleic, oleo-margaric, and probably isomeric acids, is distinguished
by its rapid drying properties. When spread in a thin layer it produces
a hard film with an opaque frosted surface, often showing a tendency to
wrinkle. Treated tung oil will dry to a clear, water-shedding, elastic
film. This oil is made by heating the raw tung oil at a comparatively
low temperature with other oils and a metallic drier such as litharge.

[Illustration: _Photographs courtesy of David Fairchild_

Aleurites Cordata (Chinese Wood Oil)

Barrel Factory at Cooperage Shop]

[Illustration: _Photographs courtesy of David Fairchild_

Aleurites Fordii (Chinese Wood Oil)

Fruit from trees at the end of fourth year]

The affinity of tung oil for rosin has resulted in the production of a
series of moderate-priced varnishes most suitable for use in floor and
deck paints or wherever great hardness is required. These varnishes are
also finding application in the manufacture of concrete, steel, and flat
wall paints; being especially suitable for the above purposes when
compounded with kauri gum japan.

[Illustration: Aleurites Fordii

Flowering specimen of the Chinese Wood Oil tree, thirty feet high and
three feet in diameter, on banks of Yangtse River, Western Szechuan,
China. Opium Poppy in the foreground]

[Illustration: Aleurites Cordata

Wood Oil tree at Riverside, California, planted in 1907. Photograph
taken in 1910, when tree had borne fifty fruits]

During the boiling of raw tung oil the temperature must not exceed much
over 400 degrees Fahrenheit. Otherwise a peculiar "hamming" will take
place, the whole mass becoming solid and of no further value as a
varnish or paint vehicle. Some peculiar internal disturbance or
rearrangement of the molecules is evidently effected by heat, and
although the reaction is not clearly understood, it has been ascribed to
auto-polymerization. Scott has stated that the phenomenon of
gelatinization is due to the exposure of the surface of the oil to the
air, and that boiling in vacuo obviates such results. The lusterless
surface produced when tung oil varnishes are dried in vitiated air would
tend to confirm the conclusion that the oil is very subject to
atmospheric influences.

Lumbang Oil, which is obtained from a tropical species of Tung, is very
similar in appearance and properties to Linseed Oil.

CONSTANTS OF TUNG OILS

  =====+=========+============+==============+==========
       | Sp. Gr. | Iodine No. |Saponification| Acid No.
       |         |            |     No.      |
  -----+---------+------------+--------------+----------
  No. 1|   .944  |    166     |     188      |   3.6
  No. 2|   .940  |    164     |     184      |   1.8
  =====+=========+============+==============+==========

[Illustration: _Photographs courtesy Alpin I. Dunn_

Menhaden Net drying in the Sun]

[Illustration: Transporting Menhaden from net to deck of boat, in
swinging basket]

[Illustration: A big catch of Menhaden made off Narragansett Bay]

=Menhaden Oil.= Of all the marine-animal oils, such as seal, herring,
sardine, whale, and menhaden, the latter is the most valuable. It is
produced by steam digestion and pressure of the menhaden or "piogey"
fish, which are caught in great quantities off the Atlantic Coast.
Prompt cooking and treatment of the fish results in a light-colored oil
having very little odor, the residue left in the presses being of great
value as a fertilizer. Although several grades of oil termed crude,
brown, light, etc., are produced, the most satisfactory for use in paint
is that grade termed "light winter pressed." This oil is of a pale straw
color and has a high iodine number which is responsible for its rapid
drying value. It contains less of the stearates that precipitate from
crude oil, but sufficient to render its film water-shedding and elastic.
The presence of too great a quantity of stearates is apt to result in a
very soft film, and the use of hard driers, such as the metallic
tungates, is therefore advisable with menhaden oil. When mixed with
linseed oil paints the odor of menhaden oil is sometimes noticeable, but
it disappears entirely after such paints are applied. Its use with
linseed oil in technical paints exposed to the salty air of the Coast
has given good results, often preventing "checking" and "chalking."

The following constants were determined on samples of menhaden oil
received in the writer's laboratory:

  ========+==========+==========+==============+==========
          | Sp. Gr.  |  Iodine  |Saponification|   Acid
          |          |  Value   |    Number    |  Number
  --------+----------+----------+--------------+----------
  Light   |   .927   |  175.8   |    187.9     |   7.55
  Medium  |   .925   |  178.7   |    187.6     |   6.19
  Dark    |   .927   |  178.0   |    187.3     |   7.19
  ========+==========+==========+==============+==========

=Whale Oil.= While ordinary whale oil is too dark and odorous to ever
come into extensive use as a paint oil, it is probable that the refined
oil will be utilized in the manufacture of certain technical paints.
Whale oil is boiled from chopped whale blubber, the first trying being
the lightest in color, while the later tryings, as well as the product
made from bones, are of darker color and of very bad odor. Oil of
mirbane is often used to mask this odor. The oil contains large
quantities of stearin and palmitin, as well as wax-like constituents
which are apt to be thrown out of solution in very cold weather, or when
the oil is mixed with other oils. The refined oil, when ground with lead
and zinc pigments and mixed with equal parts of linseed oil and treated
tung oil, dries to an elastic and soft film. Experiments are being made
to utilize whale oil in the linoleum industry.

The analyses of samples of whale oil tested by the writer are as
follows:

  =============+=========+========+==============+============
               | Sp. Gr. | Iodine |Saponification| Free Fatty
               |         | Value  |    Number    |    Acid
  -------------+---------+--------+--------------+------------
  Light Refined|  .924   |  148   |    190.2     |    1.2
  Dark Yellow  |  .920   |  142   |    187       |    7.0
  Dark Brown   |  .910   |  140   |    184       |   18.0
  =============+=========+========+==============+============

=Sunflower Oil.= Sunflower oil is produced largely in Russia and
Hungary, finding favor in those countries as an edible oil. The ripe
seeds of the sunflower plant contain over 30% of oil which is very pale
in color and of a pleasant smell. It has been found that sunflowers may
be grown to advantage in dry parts of the United States, and if suitable
yields are obtained from a few experimental acres now being cultivated,
the industry may receive encouragement in this country. The oil should
be well suited for varnish making, and although the iodine number is not
very high, it dries quite rapidly.

[Illustration: Russian Sunflower Seeds]

CONSTANTS OF SUNFLOWER OIL

  ========+============+================+======
  Sp. Gr. | Iodine No. | Saponification | Acid
          |            |      No.       |  No.
  --------+------------+----------------+------
    .929  |    128     |      188       |  4
  ========+============+================+======

=Cottonseed Oil.= This oil is expressed from the seed of the cotton
plant, varying in color according to the time of its pressing and degree
of refinement. Being edible as well as highly suited for soap making,
very little of it comes into the market as a paint oil. It contains
large quantities of stearin and has a low iodine value, making it a slow
drying oil. Some samples are extremely light in color and contain less
mucilaginous matter and foots than is present in ordinary varieties.

CONSTANTS OF COTTONSEED OIL

  ========+============+================+======
  Sp. Gr. | Iodine No. | Saponification | Acid
          |            |      No.       |  No.
  --------+------------+----------------+------
    .922  |    106     |      190       | 2.4
  ========+============+================+======

=Corn Oil.= As a by-product in the manufacture of starch and alcoholic
liquids, this material comes into the market having a golden yellow
color, and an odor resembling fermented grain. It has a lower drying
value than cottonseed oil, and its use in the paint industry will
probably be limited to color grinding, where an oil with a semi-drying
value is often desired. Like cottonseed oil, it belongs more properly to
the soap oil class. It contains glycerides of linoleic and especially
palmitic acid.

ANALYSIS OF CORN OIL

  ========+============+================+=====
  Sp. Gr. | Iodine No. | Saponification | Acid
          |            |      No.       |  No.
  --------+------------+----------------+-----
    .925  |    118     |      191       | 9.5
  ========+============+================+=====

=Rosin Oil.= By the dry distillation of rosin, there is yielded a series
of heavy dark oils consisting principally of hydrocarbons, resinous
bodies, and free acid. These oils vary in their saponification number
from 10 to 60, while their unsaponifiable value averages about 80. Of
the grades termed first, second, third, and fourth run, the latter two
are superior for use in paints, as a rule containing less free acid than
the preliminary runs. Treatment with steam and alkali serve to
neutralize the acid nature of the oils and to remove impurities. Refined
oils are lighter in color and are often blown and bodied to fairly rapid
drying products, especially when treated with manganese driers. Rosin
oils are seldom used with lead pigments, on account of the presence of
sulphur in the oils, which would result in darkening. Rosin oil paints
work very smoothly, even when they are curdled, producing glossy
surfaces. The rapid checking of rosin oil paints on wooden surfaces bars
the use of this oil for such purposes.

ANALYSES OF ROSIN OILS

  ==+=========+============+================+======
    | Sp. Gr. |   Iodine   | Saponification | Acid
    |         |   Value    |      No.       |  No.
  --+---------+------------+----------------+------
  A |   .966  |     41     |       27       | 16.7
  B |   .99   |     48     |       38       | 10.0
  ==+=========+============+================+======

=Hydrocarbon Oils.= Several grades of neutral or mineral oils, varying
somewhat in gravity, color, and quality, are produced as the last
distillate in the refining of petroleum. These oils when mixed with
drying oils and strong driers find application in the manufacture of
some freight-car, barn, and other paints which sell at a low price. A
small percentage of mineral oil is said to be valuable in structural
steel paints, acting as a preventative of hard drying and thus keeping
the film soft and elastic. Streaking and sweating is apt to ensue if any
great quantity is used. Mineral oils have a characteristic bloom,
showing a greenish fluorescence when examined by transmitted light. This
bloom is due to the presence of some strongly fluorescent material which
is shown up with intensity when mineral oils are exposed to ultraviolet
rays such as emanate from an enclosed arc light. Outerbridge[1] first
proposed this test for mineral oils, and he has worked out a
"fluorescent scale," by which very small percentages of hydrocarbon oils
may be detected in other oils. Several types of so-called debloomed oil
have been placed upon the market, and although such oils appear under
ordinary light conditions to be free from bloom, they fluoresce quite
strongly when given the Outerbridge test.

  [1] Alexander E. Outerbridge, Jr.: "A Novel Method of Detecting
      Mineral Oil and Resin Oil in Other Oils." Proc. 14th Annual Meet.,
      Amer. Soc. for Testing Mater., Atlantic City, N.J., June 28, 1911.

[Illustration: View of Stills Where Petroleum Paint Thinners are
Manufactured (Waverly)]

ANALYSIS OF DEBLOOMED MINERAL PAINT OIL[2]

  ========+============+================+=====
  Sp. Gr. | Iodine No. | Saponification | Acid
          |            |      No.       |  No.
  --------+------------+----------------+-----
    .92   |     12     |       4        |  0
  ========+============+================+=====

  [2] Oil of mirbane present, probably as a deblooming agent, or to mask
      the odor.

=Pine Oil.= This oil is produced by the redistillation of the heavy,
high boiling point fractions resulting from the steam distillation of
wood turpentine. It is a heavy straw-colored oil, and should be of some
use in the paint and varnish industry, where a high boiling point
solvent with an oxidizing principle is desired. It will probably find
application in the manufacture of Baking Japans, Asphalt Paints and
Enamels. Its oxidizing and solvent values are very high. It has a
distinctive sweet pine smell, which makes it popular in the manufacture
of turpentine substitutes from petroleum spirits.

The writer has examined samples of this material, and the following
appear to be of the best grade:

CONSTANTS OF PINE OILS

  ==========================+======================+====================
                            |        No. 1         |         No. 2
  --------------------------+----------------------+--------------------
  Color                     |Straw Color           |Light Yellow
  Specific Gravity at 15° C.|.934                  |.936
  Boiling Point             |192° C.               |202° C.
  Distillation              |95% distils between   |95% distils between
                            |  192-270° C.         |  202-280° C.
  Residue on Evaporation    |14.34%                |14.60%
  Polymerization Test       |3-2/3% unpolymerized  |2-1/2% unpolymerized
                            |  at end of 1/2 hour  |  at end of 1/2 hour
  Flash-Point               |72° C.                |76° C.
  Spot Test                 |Leaves no grease spot |Same as Pine Oil No.
                            |but only evaporates   |1.
                            |completely in 24 hours|
  ==========================+======================+====================

=Turpentine.= By direct fire or steam distillation of the sap drippings
collected in pockets cut into pine trees, there is obtained the
turpentine of commerce. It consists largely of pinene and isomeric
terpenes, and has the property of attracting oxygen, with the formation
of peroxides which stimulate the drying of oils. It is a high-grade
solvent for various gums, and is therefore used in the manufacture of
many lacquers as well as for thinning down oil-gum varnishes.

REQUISITE CONSTANTS OF PURE GUM TURPENTINE

  Color                        Water White
  Specific Gravity at 15° C.   .862-.875
  Boiling Point                About 156° C.
  Distillation                 95% should distil between 153 and 165° C.
  Residue on Evaporation       Not over 2%
  Polymerization               Not over 5% should remain unpolymerized
                               at end of half hour
  Flash-Point                  Over 40.5° C.
  Spot Test                    No grease spot should remain when dropped
                               on paper and allowed to evaporate
  Water                        None

=Wood Turpentine.= High-grade wood turpentine is now produced by the
steam distillation of finely cut fat pine wood. The lower-grade
qualities are often produced from the destructive distillation of
sawdust, stumpage, etc., and these products, on account of their content
of formaldehyde, are objectionable in odor. In the steam distillation
process, however, a high quality product is obtained by cutting out the
heavy fractions and redistilling the lower and purer fractions. It has a
high oxidizing value, causing the rapid drying of paints and varnishes
to which it has been added. Its solvent value is often greater than that
of gum turpentine. When properly refined it has a sweet smell and is to
be highly recommended.

Analyses of samples of pure wood turpentine which have come to the
writer for examination follow:

  ======================+==========================+====================
                        |           No. 1          |        No. 2
  ----------------------+--------------------------+--------------------
  Sp. Gr. at 15° C.     |.862                      |.862
  Boiling Point         |158° C.                   |162° C.
  Distillation: 95%     |                          |
    distils between     |158 and 185° C.           |162 and 177° C.
  Residue on Evaporation|1.03%                     |3.06%
  Polymerization Test   |4.1% remains unpolymerized|0.1 cc. out of 6 cc.
                        |at end of 1/2             |  unpolymerized =
                        |hour                      |  1.66%
  Spot Test             |No grease spot on         |No grease spot on
                        |  evaporation             |  evaporation
  Odor                  |Excellent                 |Not objectionable
  Color                 |Water White               |Water White
  Flash Point           |                          |47.6° C.
  ======================+==========================+====================

=Petroleum Spirits.= There are produced from Texas crude oil which has
an asphaltum base, and Pennsylvania crude oil which has a paraffin base,
high boiling-point petroleum spirits which have come into wide use as
paint and varnish thinners. When such materials have the proper
evaporating value, high flash-point and freedom from sulphur, they are
to be highly recommended as paint thinners. The following shows the
analyses of a few of these materials examined in the writer's
laboratory:

PETROLEUM SPIRITS

  =======================+=============+============+==============
                         | Texas Base  | California | Penna. Base
                         |             |    Base    |
  -----------------------+-------------+------------+--------------
  Color                  | Water White | White      | Water White
  Specific Gravity       | .811        | .79        | .81
  Boiling Point          | 156° C.     | 138° C.    | 146° C.
  Flash-Point            | 44° C.      | 40.5° C.   | 43° C.
  Residue on Evaporation | .2          | .15        | .12
  =======================+=============+============+==============

=Benzol.= "Solvent naphtha" or 160-degree benzol is a product obtained
from the distillation of coal tar, differing from benzine, a product
obtained from the distillation of petroleum. It is a valuable thinner to
use in the reduction of paints for the priming of resinous lumber and
refractory woods such as cypress and yellow pitch pine. The penetrating
and solvent values of benzol are high, and it often furnishes a unison
between paint and wood, that is a prime foundation to subsequent
coatings, preventing the usual scaling and sap exudations which often
appear on a painted surface. Because of the great solvent action of
benzol, it should never be used in second and third coatings. The writer
has successfully painted inferior grades of cypress with a paint
containing benzol in the priming coat.

=Benzine.= Benzine is seldom used in paints on account of its rapid
evaporation, which is apt to cause pinholing of films and other surface
defects. In paints of the dipping type where rapid evaporation is
essential, benzine finds its widest application.



CHAPTER II

A STUDY OF DRIERS AND THEIR EFFECT


The proper drying of oils and their behavior with various siccatives in
varying quantity is an interesting problem, and obviously of
considerable importance from a practical standpoint. Unfortunately there
is a decided scarcity of reliable literature dealing with the subject
for the guidance of those concerned in the manufacture or application of
siccative products. Furthermore, when the problem is investigated, it is
not difficult to see why this is so.

=Uniform Conditions.= At a glance it is evident that a decided obstacle
in experimentation on the drying properties of oils is the difficulty in
obtaining identical conditions for comparative purposes. Inasmuch as a
multitude of factors, such as uniformity and homogeneity of the driers
and the oils themselves, intensity and source of light, temperature,
uniformity of application, and many others, play a decisive part in the
siccative tendencies of oils, the resources and ingenuity of the chemist
engaged in the research are severely taxed.

=Oxygen Absorption.= It is a well-known fact that linseed oil, when
applied to a clean surface, such as a glass plate, will undergo
oxidation and take up oxygen to the extent of about 16%, forming a hard,
elastic, non-sticky product which has been called linoxyn. This
material, unlike the oil from which it has been formed, is insoluble in
most solvents. Other oils, such as cottonseed, hemp, rape, olive, etc.,
are more fully satisfied in nature and have not the power to absorb the
amount of oxygen taken up by linseed oil.

In carrying out the following tests, on the drying of oils, a quantity
of pure linseed oil of the following analysis was secured:

  Specific gravity at 15° C.             0.934
  Acid number                            5
  Saponification number                191-1/2
  Iodine number                        188

This oil was distributed into a number of 8-oz. oil sample bottles, and
to a series of these bottles was added varying quantities of a very
concentrated drier made by boiling oil to 400 degrees Fahrenheit in an
open kettle, with the subsequent addition of lead oxide. The amount of
drier added to each bottle varied according to the percentage desired;
being calculated on the lead content of the drier, which was very
accurately determined by analysis.

There was secured in this manner a series of oils containing varying
amounts of lead oxide, and from this lot was selected a certain number
of samples which would be representative and typical of paint vehicles
now found in the market.

Another series of tests were made by combining with a large number of
samples of pure linseed oil as used above, various percentages of a
manganese drier made by boiling oil at 400° F. and incorporating
therewith manganese dioxide.

Still another series of tests were made upon a number of oils into which
were incorporated various small quantities of lead oxide and manganese
oxide together, using the standard driers made in the above manner, all
of which were carefully analyzed to determine their contents.

In view of the errors in manipulation that could occur where so many
tests were made, it was not deemed advisable, in carrying out the tests,
to use glass plates on which only a minute quantity of oil could be
maintained. A much better solution of the difficulty presented itself in
using a series of small, round, crimped-edge tin plates, about three
inches in diameter, such as are used for lids of friction-top cans.

With paints it is impossible to secure films as thin as those presented
by layers of oil on glass, nor would it be desirable to secure films of
this same relative thickness. For this reason an endeavor was made to
conduct the following tests with films of the same relative thickness as
that possessed by the average coating of paint. The drying of the films
did not take place in the same short period, nor in the same ratio, as
with the thin layer that is secured by flowing oil upon glass. The
results, however, are more practical, and of greater value to the
manufacturer.

The cans were carefully numbered in consecutive order, corresponding to
the numbers on the various samples of oil. A very small quantity of oil
was placed in each of the can covers, which were previously weighed, and
allowed to distribute itself over the bottom surface thereof. Reweighing
of the covers gave the amount of oil which was taken for each test. The
test samples in the covers were all placed in a large box with glass
sides, having a series of perforated shelves. In the side of this box is
an opening through which a tube was passed, carrying a continual current
of air washed and dried in sulphuric acid. Oxidation of the oil films
commenced at once, and the amount of oxygen absorbed was determined at
suitable periods by weighing, the increase in weight giving this factor.
This test was kept up for a period of twenty days.

A test was also made in the same manner with a current of damp air
passing into the box, to observe the relative oxidation under such
conditions. A chart of the results obtained has been made (Table VI), to
show the effect of the various driers.

=Results of Tests.= The following outline will present to the mind of
the reader the most salient points which have been gleaned from these
experiments, and which should give the manufacturer definite knowledge
as to the best percentage of oxides to use either in boiled oil, paints
or varnishes.

In the case of lead oxide, an increase in the percentage of lead oxide
in the oil causes a relative increase in the oxygen absorption, but when
a very large percentage of lead has been added, the film of oil dries to
a leathery skin.

In the case of manganese oxide, the increase in oxygen absorption on the
first day is much more pronounced than is the case with lead oxides.
Furthermore, the oxidation of manganese oils seems to be relative to the
increase in manganese up to a certain period, when the reverse of this
law seems to take place, and beyond a certain definite percentage of
manganese, added percentages seem to be of no value. It was furthermore
observed that the films dry to a more brittle and harder skin than is
the case when lead oxide is used. The oxygen absorption with oils high
in manganese has been noticed to be excessive, and the film of oil
becomes surface-coated, drying beneath in a very slow manner; a
condition that often leads to checking. The critical percentage where
the amount of manganese appears to give the greatest efficiency seems to
be 0.02%. This critical percentage, as it may be termed, should not be
exceeded, and any added amount of manganese has the effect of making the
film much more brittle and causes the so-called "burning up" of the
paint. The loading of paint with drier and the bad result therefrom may
be explained to some extent from the above results.

TABLE VI--LINSEED OIL AND MnO_{2} (MANGANESE) DRIER--TEST NO. 1

  =========+=========+====+====+====+====+====+====+====+====+====
  Per cent.|         |0.02|0.05|0.15|0.25|0.35|0.45|0.55|0.70|1.00
  MnO_{2}  |         |    |    |    |    |    |    |    |    |
  ---------+---------+----+----+----+----+----+----+----+----+----
           |{  1 day |0.08|0.11|0.16| -- |3.21|3.46|3.27|3.01|2.76
           |{  2 days|0.16|5.88|4.48| -- |3.63|4.01|3.70|3.51|3.18
           |{  3 days|0.21|6.79|4.61| -- |3.83|4.31| -- |3.91| --
           |{  4 days| -- | -- |4.64| -- | -- | -- | -- | -- | --
           |{  5 days|3.01|6.84| -- | -- |4.13|4.68|4.19|3.91|3.99
           |{  6 days|8.00| -- |4.88| -- |4.37| -- |4.51|4.32|4.13
  Per      |{  7 days|8.58|6.92|4.90| -- |4.48| -- |4.61|4.52|4.23
  cent.    |{  8 days|9.06| -- |5.03| -- |4.55|5.23|4.77|4.62|4.44
  gain     |{  9 days| -- | -- |5.12| -- |4.63|5.40|4.94|4.79|4.51
           |{ 10 days|9.07|6.89|5.18| -- |4.81|5.47| -- |4.98|4.73
           |{ 11 days|9.15|7.03| -- | -- | -- | -- | -- | -- | --
           |{ 12 days| -- | -- | -- | -- |4.98| -- |5.45|5.33|5.22
           |{ 13 days|9.22|7.17| -- | -- |5.25|6.00|5.60|5.42|5.33
           |{ 14 days|9.25|7.18|5.55| -- | -- | -- | -- | -- | --
           |{ 20 days| -- |7.21|5.81| -- |5.84|6.70|5.94|5.84|5.77
  =========+=========+====+====+====+====+====+====+====+====+====

TABLE VII--LINSEED OIL AND MnO_{2} (MANGANESE) DRIER--TEST NO. 2 (CHECK)

  =========+=========+====+====+====+====+====+====+====+====+====
  Per cent.|         |0.02|0.05|0.15|0.25|0.35|0.45|0.55|0.70|1.00
  MnO_{2}  |         |    |    |    |    |    |    |    |    |
  ---------+---------+----+----+----+----+----+----+----+----+----
           |{  1 day | -- |3.12|4.42|3.86| -- |3.19|2.98|3.27|2.56
           |{  2 days| -- |6.15|4.73| -- | -- |3.51|3.28|3.70|2.96
           |{  3 days|0.28|6.29| -- |4.12|3.72| -- |3.39|3.71|3.15
           |{  4 days|3.83|6.32|4.75|4.21|3.87|3.61|3.58|4.05|3.43
  Per      |{  5 days|6.64| -- |4.84|4.23|3.94|3.73|3.65|4.21|3.56
  cent.    |{  6 days|8.61| -- |4.87| -- |4.08|3.81|3.78|4.35|3.73
  gain     |{  7 days|9.07|6.35|5.00|4.41|4.18|3.91|3.85|4.54|3.87
           |{  9 days|9.25|6.39|5.16| -- |4.44|4.11|4.21|4.63|4.26
           |{ 11 days| -- | -- | -- |4.63|4.59|4.36|4.31|5.07|4.46
           |{ 16 days| -- |6.43|5.30|4.91|4.83|4.72|4.71|5.40|4.87
  =========+=========+====+====+====+====+====+====+====+====+====

TABLE VIII--LINSEED OIL AND PbO (LEAD) DRIER

  =====+=====+=====+=====+=====+=====+======+======+=====+======+=====+====+====
   Per |     |     |     |     |     |      |      |     |      |     |    |
  cent.|     | 0.00| 0.05| 0.10| 0.30| 0.50 | 0.70 | 1.00| 1.30 | 1.60|1.30|1.60
   PbO |     |     |     |     |     |      |      |     |      |     |    |
  -----+-----+-----+-----+-----+-----+------+------+-----+------+-----+----+----
       |{ 1  |0.042|0.049|0.092|0.058| 0.066| 0.062|0.062| 0.079|0.039|0.14|0.72
       |{day |     |     |     |     |      |      |     |      |     |    |
       |{ 2  |0.098|0.104|0.153|0.116| 0.158|  --  |0.194| 4.83 |4.79 |5.27|6.11
       |{days|     |     |     |     |      |      |     |      |     |    |
       |{ 3  |0.128|0.159|0.170|0.137| 0.279| 0.185|7.11 | 8.60 |5.35 |7.89|8.28
       |{days|     |     |     |     |      |      |     |      |     |    |
       |{ 4  |0.164|0.214|0.206|0.178|   -- | 4.07 |7.39 | 9.55 |8.53 |7.93|8.68
       |{days|     |     |     |     |      |      |     |      |     |    |
       |{ 5  |0.176|  -- |0.306|  -- | 0.340| 7.60 |7.47 | 9.87 |8.78 |8.18| --
       |{days|     |     |     |     |      |      |     |      |     |    |
  Per  |{ 6  |0.188|0.231|  -- |0.243| 0.472| 9.36 |7.64 |10.01 |9.00 |8.24|9.09
  cent.|{days|     |     |     |     |      |      |     |      |     |    |
  gain |{ 7  |0.206|0.251|  -- |0.253| 1.080|10.06 | --  |10.14 | --  | -- | --
       |{days|     |     |     |     |      |      |     |      |     |    |
       |{ 8  |0.212|0.253|  -- |0.280| 4.80 |10.38 |7.70 |10.22 |9.05 | -- | --
       |{days|     |     |     |     |      |      |     |      |     |    |
       |{ 9  |0.226|0.291|0.306|0.331| 7.36 |10.41 |7.73 |10.23 |9.07 | -- | --
       |{days|     |     |     |     |      |      |     |      |     |    |
       |{13  |0.327|0.428|0.510|0.674|11.01 |10.67 |7.91 |10.48 |9.29 |8.62| --
       |{days|     |     |     |     |      |      |     |      |     |    |
       |{15  |0.466|0.455|0.650|2.41 |11.05 |  --  |7.92 |10.50 |9.30 | -- | --
       |{days|     |     |     |     |      |      |     |      |     |    |
       |{20  |0.521|1.08 |1.78 |8.76 |11.25 |10.67 |7.98 |10.52 |9.36 | -- | --
       |{days|     |     |     |     |      |      |     |      |     |    |
  =====+=====+=====+=====+=====+=====+======+======+=====+======+=====+====+====

TABLE IX--LINSEED OIL AND PbO (LEAD) AND MnO_{2} (MANGANESE)--COMBINATION
DRIER

  =================+========+=====+=====+======+======+====+=====+====
  Per cent. PbO    |        | 0.1 | 0.3 | 0.5  | 0.7  |0.9 | 1.1 |1.4
  -----------------+--------+-----+-----+------+------+----+-----+----
  Per cent. MnO_{2}|        |.005 |.015 | 0.025| 0.35 |0.45| 0.55|0.7
  -----------------+--------+-----+-----+------+------+----+-----+----
                   |{ 1 day |0.026|0.061| 0.055| 0.022|0.16| 0.11|3.06
                   |{ 2 days|0.094|0.087| 0.143| 0.16 |5.21| 6.28|3.37
                   |{ 3 days|0.118| --  | 0.17 | 4.23 |7.63| 8.31|3.74
                   |{ 4 days| --  |0.11 | 0.23 | 7.36 |8.87| 9.20|4.02
                   |{ 5 days|0.120|0.12 | 0.29 | 9.04 |9.13| 9.37|4.17
  Per cent. gain   |{ 6 days|0.17 |0.13 | 1.44 | 9.88 |9.26| 9.51|4.34
                   |{ 7 days|0.21 |0.18 | 4.65 |10.11 |9.28|  -- |4.45
                   |{11 days|0.30 |0.26 |10.03 |10.35 |9.61| 9.85|5.11
                   |{12 days| --  | --  |  --  |10.45 |9.66|  -- | --
                   |{13 days|0.35 |0.54 |10.37 |10.51 |9.67|10.03|5.33
                   |{18 days|0.49 |3.43 |10.38 |10.62 |9.68|  -- |5.73
  =================+========+=====+=====+======+======+====+=====+====

In the same way with lead driers, excessive amounts of lead oxide seem
to have no beneficial effects on the drying of an oil, and when the
percentage which seems to be the most beneficial, namely 0.5% lead
oxide, is exceeded, the film is apt to become brittle.

Oils containing lead oxide driers are less influenced in their drying
tendencies by conditions of moisture in the atmosphere than oils
containing manganese, but frequently, however, the former dry much
better in a dry atmosphere. As a general rule, varnishes rich in
manganese dry more quickly in a dry atmosphere, while those containing
small quantities dry more quickly in a damp atmosphere.

=Volatile Products Formed.= It was furthermore noticed in these tests
that sulphuric acid, placed in dishes on the bottom of the large box in
which the samples of oil were drying, was discolored and turned brown
after several days, showing that the acid had taken up some material of
a volatile nature that was a product of the oxidation.

Another curious feature of these tests was the development of a peculiar
aromatic odor which was given off by the oils upon drying in dry air.
When the oils were dried in moist air, a rank odor resembling propionic
acid was observed, and this led the observer to believe that a reaction
was effected by the absorbed oxygen, that caused the glycerin combined
with the linoleic acid as linolein to split up into evil-smelling
compounds. It has been suggested that the oxygen first attacks the
glycerin, transforming it into carbonic acid, water, and other volatile
compounds, which are eliminated before the oil is dried to linoxyn.
Toch,[3] however, has shown that the drying of linseed oil gives off
only very small percentages of carbon dioxide. Mulder has observed that
in the process of linseed oil being oxidized, glycerin is set free,
which becomes oxidized to formic, acetic, and other acids, while the
acid radicals are converted by oxygen into the anhydrides, from which
they pass by further oxidation into linoxyn.

  [3] Toch: The Chem. and Tech. of Mixed Paints, p. 89. D. Van Vostand
      Co., N. Y.

=Auto-Oxidation of Oil.= The theory of auto-oxidation of linseed oil has
been very ably treated by Blackler, whose experiments indicated that
during the drying process the slow absorption of oxygen was, at a
critical period, followed by a rapid absorption, which he attributes to
the presence of peroxides. The materials produced by this peroxide
formation may act as catalyzers and accelerate the formation of more
peroxide. Lead and manganese oxides may also be oxidized to peroxides by
the action of oxygen, and in this event might act as very active
catalyzing agents or carriers of oxygen. Blackler's statement, that the
presence of driers do not increase, but have a tendency to decrease the
initial velocity of oxygen absorption, has been confirmed by these
experiments, but it has been noticed throughout the tests that the
driers have an accelerative action at a later period.

=Effect of Metals on Drying of Oils.= Some most interesting results were
secured by dipping extremely fine copper gauze into linseed oil, and
then suspending the gauze in the air. The adhesion of the oil to the
copper caused the formation of films between the network, and remarkable
drying action was observed. The copper or any superficial coating of
copper oxide which may have been present on the metal, undoubtedly
affected the result to some extent. It has been found that metallic lead
is even more efficient than copper in this respect, but this may be due
to the action of free acid in the linseed oil, forming lead linoleates,
products that greatly accelerate drying. Another interesting experiment
was made by immersing pieces of gauze cloth in linseed oil. After the
excess oil had been removed, by pressing, the cloth was again weighed to
determine the amount of oil used for the experiment. The increase in
oxygen absorption in this case was very rapid, and the result obtained
confirmed the results in the other experiments.

In order to secure a more evenly distributed state of the oil, tests
were conducted by saturating pieces of stiff blotting papers, and, after
exposure, weighing as usual.

=Influence of Light.= The influence of light on the drying of oils is
unquestionably a potent one. The practical painter knows that a certain
varnish will dry quicker when exposed to the light than when in the
dark.

Chevreul was one of the first pioneers in this field of research to
observe the effects of colored lights on drying, and he claimed that oil
exposed under white glass dried more rapidly than when exposed under red
glass, which eliminates all light of short wave lengths.

Genthe obtained interesting results in the drying of oil submitted to
the effect of the mercury lamp. Oxidation without driers was effected
probably through the formation of peroxides. In commenting on this
subject, Blackler[4] gives a description of the use of the Uveol Lamp,
which is similar to the mercury lamp, but has, instead of a glass casing
which cuts off the valuable rays, a fused-quartz casing which allows
their passage.

  [4] M. B. Blackler: "The Use and Abuse of Driers," P. and V. Society,
      London, Sept. 9, 1909.

=Driers in Boiled Oil.= In the boiling of linseed oil, by certain
processes the oil is heated to 250° F. and manganese resinate is
incorporated therein. It goes into solution quite rapidly. In other
processes the oil is heated to 400° F. or over, and manganese as an
oxide is boiled into the oil. Although it is unsafe to say that a small
percentage of rosin, such as would be introduced by the use of resinate
driers, is not harmful, yet it appears that this process should give a
good oil, inasmuch as it has been found that no matter whether the
manganese is added to the oil, as a resinate, borate or oxide,
practically the same drying effect is noticed in every case where the
percentage of manganese is the same. It is the opinion of some, however,
that the resinate driers are not as well suited for durability as oxide
driers. However, if a boiled oil is found to contain on analysis a small
percentage of rosin less than 0.5% or a percentage only sufficient to
combine with the metal present, it should not be suspected of
adulteration. Practical tests should be made with such oil along with an
oil made with an oxide drier, before pronouncing on their relative
values. Inasmuch as the addition of certain driers to linseed oil
lessens the durability of the film, it is more practical to use the
smallest amount of drier that will serve the purpose desired, that is,
set the oil up to a hard condition which will not take dust and which
will stand abrasion.

The results of this investigation would indicate that when lead or
manganese linoleates are used, the most efficient drying is shown with
0.5% lead or with 0.02% manganese, or with a combination of 0.5% lead
and 0.02% manganese.

Until more definite results have been obtained with the _tungates_,
which will probably prove of exceptional interest as driers, the above
driers will probably be used to the greatest extent.

=Co-operative Drying Tests.= A series of important drying tests made by
members of a special committee[5] appointed by the American Society for
Testing Materials, of which the writer was chairman, is herewith shown:

  [5] Sub-Committee C of Committee D-1, on Testing Paint Vehicles. Proc.
      Amer. Soc. for Test. Mater., 1911.

"At the January meeting of Committee D-1, a sub-committee consisting of
the following members was appointed to investigate paint vehicles:

  G. B. Heckel,
  Glenn H. Pickard,
  Allen Rogers,
  A. H. Sabin,
  H. A. Gardner, _Chairman_.

"At a subsequent meeting of the sub-committee it was determined to start
the investigations with a series of tests on certain drying,
semi-drying, and non-drying oils, determining their drying values, rate
of oxygen absorption, etc., when spread out in thin films. A quantity of
the following oils was selected for the tests and subsequently secured
from sources known to be reliable:

  Lead and manganese linoleate drier.[6]
  Lithographic linseed oil.
  Boiled linseed oil (resinate type).
  Boiled linseed oil (linoleate type).
  Blown linseed oil (containing drier while being blown).
  Heavy mineral oil.
  Rosin oil.
  Soya bean oil.
  Corn oil.
  Cottonseed oil.
  Sunflower oil.
  Menhaden oil.
  Chinese wood oil, raw.
  Chinese wood oil, treated.
  Perilla oil.[7]
  Lumbang oil.[7]
  Dry rosin 20%, boiled in 80% linseed oil.

  [6] The drier used, upon analysis, showed the presence of 4.36% PbO
      and 2.51% MnO_{2}.

  [7] The lumbang and perilla oils were imported and arrived subsequent
      to the starting of the tests. They were therefore not included in
      the tests.

"Four-ounce sample bottles of each oil were sent to the Committee
members, with the request to proceed with the tests along the lines
agreed upon at the Committee meeting. The instructions for making these
tests are outlined as follows:

(_a_) A series of small glass plates, approximately 5 by 7 ins., are to
be prepared by each member of the Committee. These plates are to be
thoroughly cleaned and carefully numbered and weighed upon a chemical
balance. The oils to be used for the tests are to be numbered
corresponding to the plates. A test of each oil is to be made by
painting it upon the surface of a glass plate with a camel's-hair brush,
subsequently weighing the plate and the oil. These tests are to be
exposed under constant conditions of temperature, if possible, for three
weeks' time, making weighings of each plate every day for six days and
then every other day for twelve days.

(_b_) Another series of tests shall be made, in which 80% of raw linseed
oil is to be combined with each of the above oils named. Previous to
making any of the tests, _there should be added to each oil, or to each
combination, 5% of a drier containing lead and manganese_. The drier to
be used is of the standard grade submitted, together with the oil
samples. The results of the tests are to be charted and submitted at the
end of the tests, so that they may be compared with the results obtained
by each member of the Committee.

(_c_) If possible, the oils and mixture of oils used in the above tests
are to be ground with pure silica and painted out upon sized paper,
three-coat work, the films to be stripped and tested for strength upon a
paint filmometer, at two periods two months apart."

The drying of oils to a firm surface when spread in a thin layer is
accompanied by an increase in weight, due to the absorption of oxygen.
The percentage of oxygen absorbed often affords a criterion of the
drying of the oil under examination, and this factor, together with data
regarding the appearance of the oil film, should be taken into
consideration when judging the value of an oil or oil mixture.
Conditions of light, air, temperature, etc., often cause great
variations in the drying of oils and the percentage of oxygen absorbed,
as shown by the results obtained in the following tests. Although it was
impossible in these tests to have the conditions under which each
experimenter worked parallel in nature, the tests afford nevertheless
considerable information for guiding future work of a similar nature.

An examination of the results obtained showed generally that the
greatest increase in weight occurred during the period in which the oil
dried up to a firm film. This occurred in most cases within 48 hours.
After this period a slight increase in weight was often noticed, and
then a more or less steady decline, varying with the oil examined. Had
the oil tests been continued for a greater length of time, a much
greater loss might have been observed.

It was impossible to include in the tests the oil-silica film work, on
account of lack of time. It is believed, however, that these tests
should be conducted, as they would throw much light on the elasticity
and strength given to paint films by various oils.

  TABLE I.--(_a_) BOILED LINSEED OIL (RESINATE TYPE)    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1997   |   0.6242  |   0.5027  |  0.6024
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    11.9    |   14.42   |   10.21   |  13.69
             |  2 |    12.5    |   13.37   |   10.00   |  13.01
             |  3 |    12.7    |   12.53   |    9.57   |  12.50
             |  4 |    13.1    |   11.7    |    9.65   |  12.29
             |  5 |    12.8    |   11.03   |    8.99   |  12.00
             |  6 |    12.7    |     --    |     --    |  12.25
             |  7 |     --     |   10.17   |    8.57   |    --
             |  8 |    12.7    |   10.34   |     --    |  11.64
             |  9 |     --     |   10.12   |    8.93   |    --
  Percentage | 10 |    12.6    |   10.00   |     --    |  10.73
  Increase   | 11 |     --     |     --    |    8.81   |    --
  in Weight, | 12 |    12.8    |    9.69   |     --    |  10.68
  in Days.   | 13 |     --     |     --    |    9.31   |    --
             | 14 |    12.8    |     --    |     --    |  11.18
             | 15 |     --     |    9.04   |    9.43   |    --
             | 16 |    12.7    |     --    |     --    |  10.68
             | 17 |     --     |    8.68   |     --    |    --
             | 18 |    12.9    |     --    |    9.11   |    --
             | 19 |     --     |    8.13   |     --    |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Dried to    |           |           |Tacky at end
                  |firm, smooth|           |           |of 1st day.
                  |film in 2   |           |           |Nearly dry,
                  |days        |           |           |end of 2d day.
                  |            |           |           |Perfectly dry,
                  |            |           |           |end of 10th
                  |            |           |           |day.
  ----------------+------------+-----------+-----------+--------------

  (_b_) BOILED LINSEED OIL (RESINATE TYPE)    20 PER CENT.
        RAW LINSEED OIL                       80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1933   |   0.3660  |   0.4640  |     --
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    13.6    |    0.57   |   12.48   |     --
             |  2 |    14.7    |    1.66   |   11.92   |     --
             |  3 |    14.9    |   10.50   |   11.49   |     --
             |  4 |    14.9    |   13.30   |   11.10   |     --
             |  5 |    14.8    |     --    |   10.84   |     --
             |  6 |    14.8    |     --    |     --    |     --
             |  7 |     --     |   12.51   |    9.48   |     --
             |  8 |    14.8    |     --    |     --    |     --
             |  9 |     --     |   11.40   |    7.41   |     --
  Percentage | 10 |    14.8    |     --    |     --    |     --
  Increase   | 11 |     --     |     --    |    7.56   |     --
  in Weight, | 12 |    14.7    |   10.20   |     --    |     --
  in Days.   | 13 |     --     |     --    |    8.36   |     --
             | 14 |    14.5    |     --    |     --    |     --
             | 15 |     --     |    9.84   |    8.54   |     --
             | 16 |    14.7    |     --    |     --    |     --
             | 17 |     --     |     --    |     --    |     --
             | 18 |    14.7    |     --    |    8.51   |     --
             | 19 |     --     |     --    |     --    |     --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Dried to    |           |           |
                  |firm, smooth|           |           |
                  |film in 2   |           |           |
                  |days.       |           |           |
  ----------------+------------+-----------+-----------+--------------

  TABLE II.--(_a_) BOILED LINSEED OIL (LINOLEATE TYPE)    100 PER CENT.

  ----------------+------------+-----------+-----------+---------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+---------------
  Wt. of Oil for  |   0.1226   |   0.5384  |   0.5696  |  0.3306
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    10.9    |   14.34   |   10.25   |  12.09
             |  2 |    12.2    |   13.26   |   10.41   |  11.33
             |  3 |    12.7    |   12.18   |   10.22   |  10.94
             |  4 |    12.5    |   11.29   |   10.16   |  11.10
             |  5 |    12.8    |   10.75   |    9.90   |  10.86
             |  6 |    12.2    |     --    |     --    |  11.25
             |  7 |     --     |    9.88   |    9.60   |    --
             |  8 |    12.2    |   10.25   |     --    |  10.87
             |  9 |     --     |   10.01   |    9.72   |    --
  Percentage | 10 |    12.4    |    9.91   |     --    |   9.72
  Increase   | 11 |     --     |     --    |    9.48   |    --
  in Weight, | 12 |    12.1    |    9.60   |     --    |  10.02
  in Days.   | 13 |     --     |     --    |    9.97   |    --
             | 14 |    12.     |     --    |     --    |  10.62
             | 15 |     --     |    9.12   |   10.36   |    --
             | 16 |    12.1    |     --    |     --    |  10.46
             | 17 |     --     |    8.37   |     --    |    --
             | 18 |    12.1    |     --    |    9.59   |    --
             | 19 |     --     |    8.30   |     --    |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Dried firmly|           |           |Tacky at end
                  |with smooth,|           |           |of 1st day.
                  |even film in|           |           |Slightly
                  |2 days.     |           |           |tacky, end 2d
                  |            |           |           |day. Dry, but
                  |            |           |           |curled, end of
                  |            |           |           |10th day.
  ----------------+------------+-----------+-----------+--------------

  (_b_) BOILED LINSEED OIL (LINOLEATE TYPE)    20 PER CENT.
        RAW LINSEED OIL                        80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1843   |   0.5790  |  0.4653   |    --
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    11.8    |   10.14   |  12.40    |    --
             |  2 |    13.9    |   15.71   |  11.90    |    --
             |  3 |    15.1    |   13.29   |  11.50    |    --
             |  4 |    15.2    |   12.12   |  11.11    |    --
             |  5 |    15.0    |   11.43   |  10.90    |    --
             |  6 |    14.6    |     --    |    --     |    --
             |  7 |     --     |   10.05   |   9.37    |    --
             |  8 |    14.6    |   10.26   |    --     |    --
             |  9 |     --     |    9.55   |   8.53    |    --
  Percentage | 10 |    14.5    |    9.32   |    --     |    --
  Increase   | 11 |     --     |     --    |   7.48    |    --
  in Weight, | 12 |    14.4    |    8.84   |    --     |    --
  in Days.   | 13 |     --     |     --    |   8.43    |    --
             | 14 |    14.4    |     --    |    --     |    --
             | 15 |     --     |    8.46   |   8.02    |    --
             | 16 |    14.6    |     --    |    --     |    --
             | 17 |     --     |    7.68   |    --     |    --
             | 18 |    14.7    |     --    |   7.27    |    --
             | 19 |     --     |    7.55   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Dried with  |           |           |
                  |smooth film |           |           |
                  |in 2 days.  |           |           |
  ----------------+------------+-----------+-----------+--------------

  TABLE III.--(_a_) LITHOGRAPHIC LINSEED OIL    100 PER CENT.

  ----------------+------------+-----------+-----------+---------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.4011   |   0.8733  |  0.8812   |  2.7318
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+-------------
             |  1 |     6.9    |    0.87   |   3.60    |   .051
             |  2 |     8.5    |    3.85   |   5.10    |   .051
             |  3 |     8.9    |    5.14   |   5.00    |   .051
             |  4 |     8.9    |    6.07   |   6.78    |   .041
             |  5 |     8.7    |    6.40   |   6.97    |   .081
             |  6 |     8.0    |     --    |    --     |   .169
             |  7 |      --    |    6.84   |   7.38    |    --
             |  8 |     8.0    |    7.22   |    --     |   .19
             |  9 |      --    |    7.36   |   7.42    |    --
  Percentage | 10 |     8.0    |    7.57   |    --     |   .752
  Increase   | 11 |      --    |     --    |   7.44    |    --
  in Weight, | 12 |     8.0    |    7.75   |    --     |  1.184
  in Days.   | 13 |      --    |     --    |   8.01    |    --
             | 14 |     8.4    |     --    |    --     |  1.641
             | 15 |      --    |    7.98   |   8.03    |    --
             | 16 |     8.4    |     --    |    --     |  2.00
             | 17 |      --    |    7.83   |    --     |    --
             | 18 |     8.3    |     --    |   7.99    |    --
             | 19 |      --    |    7.80   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Dried to    |           |           |Remained
                  |glossy, firm|           |           |sticky to 10
                  |film,       |           |           |days, and even
                  |slightly    |           |           |at end of 38
                  |crinkled in |           |           |days was
                  |2 days. Oil |           |           |slightly
                  |made very   |           |           |tacky.
                  |thick film  |           |           |
                  |on account  |           |           |
                  |of heavy    |           |           |
                  |body.       |           |           |
  ----------------+------------+-----------+-----------+--------------

  (_b_) LITHOGRAPHIC LINSEED OIL    20 PER CENT.
        RAW LINSEED OIL             80 PER CENT.

  ----------------+------------+-----------+-----------
   Observer.      |  Gardner   |   Sabin   |  Pickard
                  |            |           |
  ----------------+------------+-----------+-----------
  Wt. of Oil for  |   0.1300   |   0.7750  |  0.6538
  Test, grams     |            |           |
  -----------+----+------------+-----------+-----------
             |  1 |    10.2    |   11.35   |   9.94
             |  2 |    11.3    |   11.48   |  10.41
             |  3 |    11.9    |   10.93   |  10.39
             |  4 |    12.0    |   10.77   |  10.35
             |  5 |    11.8    |   10.25   |   9.93
             |  6 |    11.8    |     --    |    --
             |  7 |      --    |    9.51   |   9.54
             |  8 |    11.8    |    9.93   |    --
             |  9 |      --    |    9.80   |   9.36
  Percentage | 10 |    11.8    |    9.68   |    --
  Increase   | 11 |      --    |     --    |   8.99
  in Weight, | 12 |    11.8    |    9.65   |    --
  in Days.   | 13 |      --    |     --    |   9.61
             | 14 |    11.8    |     --    |    --
             | 15 |      --    |    9.51   |   9.70
             | 16 |    11.9    |     --    |    --
             | 17 |      --    |    9.07   |    --
             | 18 |    11.9    |     --    |   9.13
             | 19 |      --    |    8.67   |    --
  -----------+----+------------+-----------+-----------
  Remarks.        |Dried to    |           |
                  |firm, glossy|           |
                  |film in 2   |           |
                  |days.       |           |
  ----------------+------------+-----------+-----------

  TABLE IV.--(_A_) BLOWN LINSEED OIL    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.2105   |   0.8394  |  0.8457   |  1.0398
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     8.5    |    9.30   |   5.07    |   4.41
             |  2 |    10.2    |    8.97   |   6.16    |   4.91
             |  3 |    10.2    |    5.30   |   6.48    |   5.22
             |  4 |    10.2    |    9.30   |   6.94    |   5.62
             |  5 |    10.0    |    8.99   |   6.73    |   5.73
             |  6 |     9.9    |     --    |    --     |   6.06
             |  7 |      --    |    8.49   |   6.99    |    --
             |  8 |     9.8    |    8.89   |    --     |   6.43
             |  9 |      --    |    8.73   |   6.89    |    --
  Percentage | 10 |     9.8    |    8.89   |    --     |   6.18
  Increase   | 11 |      --    |     --    |   7.11    |    --
  in Weight, | 12 |     9.7    |    8.73   |    --     |   6.51
  in Days.   | 13 |      --    |     --    |   7.60    |    --
             | 14 |     9.8    |     --    |    --     |   6.95
             | 15 |      --    |    8.52   |   7.95    |    --
             | 16 |     9.8    |     --    |    --     |   7.00
             | 17 |      --    |    8.07   |    --     |    --
             | 18 |     9.9    |     --    |   7.86    |    --
             | 19 |      --    |    7.74   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Ropiness of |           |           |Formed skin,
                  |oil made    |           |           |end 1st day.
                  |very thick  |           |           |Slightly
                  |film, but   |           |           |tacky end 2nd;
                  |dried in    |           |           |dry, but
                  |less than 2 |           |           |curled, end of
                  |days to     |           |           |10th day.
                  |smooth film.|           |           |
                  |Films       |           |           |
                  |exhibited   |           |           |
                  |ridges.     |           |           |
  ----------------+------------+-----------+-----------+--------------

  (_b_)BLOWN LINSEED OIL         20 PER CENT.
       RAW LINSEED OIL           80 PER CENT.

  ----------------+------------+-----------+-----------
   Observer.      |  Gardner   |   Sabin   |  Pickard
                  |            |           |
  ----------------+------------+-----------+-----------
  Wt. of Oil for  |   0.0774   |   0.5329  |   0.6218
  Test, grams     |            |           |
  -----------+----+------------+-----------+-----------
             |  1 |    10.4    |   11.82   |   10.71
             |  2 |    12.8    |   12.76   |     --
             |  3 |    13.1    |   10.98   |     --
             |  4 |    12.9    |   10.39   |     --
             |  5 |    12.1    |    9.81   |     --
             |  6 |    11.9    |     --    |     --
             |  7 |     --     |    8.69   |     --
             |  8 |    12.0    |    9.15   |     --
             |  9 |     --     |    8.91   |     --
  Percentage | 10 |    11.8    |    8.97   |     --
  Increase   | 11 |     --     |     --    |     --
  in Weight, | 12 |    11.8    |    8.67   |     --
  in Days.   | 13 |     --     |     --    |     --
             | 14 |    11.7    |     --    |     --
             | 15 |     --     |    8.22   |     --
             | 16 |    11.6    |     --    |     --
             | 17 |     --     |    7.63   |     --
             | 18 |    11.8    |     --    |     --
             | 19 |     --     |    7.32   |     --
  -----------+----+------------+-----------+-----------
  Remarks.        |Dried to    |           |Glass broke.
                  |very glossy |           |
                  |film in 2   |           |
                  |days.       |           |
  ----------------+------------+-----------+-----------

  TABLE V.--(_a_) MINERAL OIL    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1632   |    --     |    --     |  0.1975
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |  [8]12.5   |    --     |    --     | [8] 8.12
             |  2 |  [8]14.2   |    --     |    --     | [8]16.22
             |  3 |  [8]16.7   |    --     |    --     | [8]21.23
             |  4 |  [8]19.4   |    --     |    --     | [8]25.58
             |  5 |  [8]19.4   |    --     |    --     | [8]28.41
             |  6 |  [8]19.5   |    --     |    --     | [8]28.92
             |  7 |      --    |    --     |    --     |      --
             |  8 |  [8]19.5   |    --     |    --     | [8]35.25
             |  9 |      --    |    --     |    --     |      --
  Percentage | 10 |  [8]19.5   |    --     |    --     | [8]35.76
  Increase   | 11 |      --    |    --     |    --     |      --
  in Weight, | 12 |  [8]19.3   |    --     |    --     | [8]43.86
  in Days.   | 13 |      --    |    --     |    --     |      --
             | 14 |  [8]19.4   |    --     |    --     | [8]45.28
             | 15 |      --    |    --     |    --     |      --
             | 16 |  [8]19.5   |    --     |    --     | [8]48.08
             | 17 |      --    |    --     |    --     |      --
             | 18 |  [8]19.5   |    --     |    --     |      --
             | 19 |      --    |    --     |    --     |      --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Oil lost in |Broken be- |Broken be- |Remained oily
                  |weight      |fore weigh-|fore weigh-|during entire
                  |throughout  |ings were  |ings were  |test.
                  |test on ac- |made.      |made.      |
                  |count of    |           |           |
                  |presence of |           |           |
                  |volatiles.  |           |           |
                  |No drying   |           |           |
                  |action ob-  |           |           |
                  |served. Film|           |           |
                  |wet at end  |           |           |
                  |of test.    |           |           |
  ----------------+------------+-----------+-----------+--------------

  [8] Lost in weight throughout test.

  (_b_) MINERAL OIL                 20 PER CENT.
        RAW LINSEED OIL             80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1884   |   0.5663  |   0.405   |   0.2598
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     6.4    |   11.51   | [9]9.66   | [9]6.69
             |  2 |     6.8    |    8.21   | [9]8.92   | [9]5.06
             |  3 |     7.2    |    6.51   | [9]6.82   | [9]2.88
             |  4 |     7.8    |    5.19   | [9]6.03   | [9]1.52
             |  5 |     8.1    |    4.36   | [9]4.68   | [9]1.29
             |  6 |     7.9    |     --    |     --    | [9]1.68
             |  7 |     --     |    2.72   | [9]2.64   |     --
             |  8 |     7.9    |    3.12   |     --    |[10]2.07
             |  9 |     --     |    2.82   |[10]0.30   |     --
  Percentage | 10 |     8.1    |    2.59   |     --    |[10]0.08
  Increase   | 11 |     --     |     --    |[10]0.56   |     --
  in Weight, | 12 |     7.8    |    2.35   |     --    |[10]0.93
  in Days.   | 13 |     --     |     --    |[10]0.04   |     --
             | 14 |     7.8    |     --    |     --    |[10]0.54
             | 15 |      --    |    1.36   |[10]0.14   |     --
             | 16 |     7.8    |     --    |     --    |     --
             | 17 |     --     |    0.53   |     --    |     --
             | 18 |     7.8    |     --    |[10]0.86   |     --
             | 19 |     --     |[10]0.14   |     --    |     --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Fair drying |           |           |Sticky, end of
                  |observed end|           |           |1st day;
                  |of 2d day.  |           |           |tacky, end of
                  |Film tacky  |           |           |2d day and end
                  |until end   |           |           |of 38 days.
                  |8th day;    |           |           |
                  |after that, |           |           |
                  |fairly firm |           |           |
                  |film shown. |           |           |
  ----------------+------------+-----------+-----------+--------------

   [9] Gained in weight throughout test.

  [10] Lost in weight throughout test.

  TABLE VI.--(_a_) SOYA BEAN OIL    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1377   |   0.3972  |  0.4366   |  0.3564
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     7.5    |    9.79   |   9.87    |   8.25
             |  2 |     8.4    |    9.69   |   9.87    |   7.58
             |  3 |     9.5    |    8.56   |   9.35    |   7.02
             |  4 |    12.8    |    7.60   |   8.66    |   6.74
             |  5 |    12.9    |    7.09   |   8.13    |   6.46
             |  6 |    12.7    |     --    |    --     |   6.74
             |  7 |     --     |    6.00   |   6.44    |    --
             |  8 |    12.6    |    6.22   |    --     |   6.46
             |  9 |     --     |    6.00   |   4.88    |    --
  Percentage | 10 |    12.5    |    5.54   |    --     |   5.40
  Increase   | 11 |     --     |     --    |   4.26    |    --
  in Weight, | 12 |    12.4    |    5.36   |    --     |   5.59
  in Days.   | 13 |     --     |     --    |   4.99    |    --
             | 14 |    12.3    |     --    |    --     |   5.80
             | 15 |     --     |    4.73   |   4.94    |    --
             | 16 |    12.3    |     --    |    --     |   5.67
             | 17 |     --     |    4.23   |    --     |    --
             | 18 |    12.3    |     --    |   4.94    |    --
             | 19 |     --     |    3.70   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Film tacky  |           |           |Sticky, end of
                  |until 3d    |           |           |1st day;
                  |day. Clear  |           |           |tacky, end of
                  |and fairly  |           |           |2d day;
                  |firm after  |           |           |slightly
                  |4th day.    |           |           |tacky, end of
                  |            |           |           |10th and 38th
                  |            |           |           |days.
  ----------------+------------+-----------+-----------+--------------

  (_b_) SOYA BEAN OIL       20 PER CENT.
        RAW LINSEED OIL     80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.2218   |   0.2877  |  0.4581   |  0.2249
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    11.5    |   12.78   |  13.16    |  11.74
             |  2 |    11.8    |   12.78   |  12.64    |  12.27
             |  3 |    12.5    |   11.74   |  11.84    |  10.38
             |  4 |    13.9    |   12.23   |  11.50    |   9.43
             |  5 |    14.0    |   10.60   |  11.01    |   9.66
             |  6 |    14.0    |     --    |    --     |   9.75
             |  7 |     --     |    9.35   |   9.15    |    --
             |  8 |    14.1    |   10.08   |    --     |  10.29
             |  9 |     --     |    9.76   |   7.29    |    --
  Percentage | 10 |    14.1    |    9.59   |    --     |   9.08
  Increase   | 11 |     --     |     --    |   6.61    |    --
  in Weight, | 12 |    13.8    |    9.59   |    --     |   8.18
  in Days.   | 13 |     --     |     --    |   7.43    |    --
             | 14 |    13.6    |     --    |    --     |   8.95
             | 15 |     --     |    9.00   |   6.96    |    --
             | 16 |    13.6    |     --    |    --     |    --
             | 17 |     --     |    8.09   |    --     |    --
             | 18 |    13.6    |     --    |   6.66    |    --
             | 19 |     --     |    8.00   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Clear, firm |           |           |Tacky at end
                  |film ob-    |           |           |of 1st and 2d
                  |served at   |           |           |days. Dry, end
                  |end of 2d   |           |           |10th day.
                  |day.        |           |           |
  ----------------+------------+-----------+-----------+--------------

  TABLE VII.--(_a_) ROSIN OIL    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.2590   |    --     |    --     |  0.4822
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     1.5    |    --     |    --     |   2.24
             |  2 |     1.5    |    --     |    --     |   2.53
             |  3 |     1.8    |    --     |    --     |   2.32
             |  4 |     3.0    |    --     |    --     |   1.27
             |  5 |     5.2    |    --     |    --     |   1.06
             |  6 |     4.9    |    --     |    --     |   0.66
             |  7 |     --     |    --     |    --     |    --
             |  8 |     4.8    |    --     |    --     |   0.24
             |  9 |     --     |    --     |    --     |    --
  Percentage | 10 |     4.8    |    --     |    --     |   0.78
  Increase   | 11 |     --     |    --     |    --     |    --
  in Weight, | 12 |     4.8    |    --     |    --     |   0.68
  in Days.   | 13 |     --     |    --     |    --     |    --
             | 14 |     4.8    |    --     |    --     |   0.41
             | 15 |     --     |    --     |    --     |    --
             | 16 |     4.8    |    --     |    --     |   0.39
             | 17 |     --     |    --     |    --     |    --
             | 18 |     4.8    |    --     |    --     |    --
             | 19 |     --     |    --     |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Tacky       |           |Too much   |Oily on 1st
                  |throughout  |           |on. Showed |and 2d days.
                  |test.       |           |constantly |Tacky, end of
                  |            |           |increasing |10 and 38
                  |            |           |loss owing |days.
                  |            |           |to the fact|
                  |            |           | that it   |
                  |            |           |did not dry|
                  |            |           |and ran off|
                  |            |           |glass.     |
  ----------------+------------+-----------+-----------+--------------

  TABLE VII.--(_b_) ROSIN OIL          20 PER CENT.
                  RAW LINSEED OIL    80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1636   |   0.7105  |  0.4016   |  0.3263
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     7.4    |    6.64   |   12.21   |  11.48
             |  2 |     7.8    |    6.40   |   11.45   |  12.02
             |  3 |     8.5    |    6.05   |   11.13   |  10.60
             |  4 |     8.5    |    5.63   |   10.53   |  10.26
             |  5 |     8.4    |    5.23   |   10.13   |  10.42
             |  6 |     8.1    |     --    |     --    |  10.42
             |  7 |     --     |    4.42   |    8.8    |    --
             |  8 |     8.0    |    4.92   |     --    |  10.95
             |  9 |     --     |    4.83   |    8.12   |    --
  Percentage | 10 |     8.0    |    4.57   |     --    |   9.96
  Increase   | 11 |     --     |     --    |    7.45   |    --
  in Weight, | 12 |     8.0    |    4.68   |     --    |   9.53
  in Days.   | 13 |     --     |     --    |    8.27   |    --
             | 14 |     7.9    |     --    |     --    |   9.96
             | 15 |     --     |    4.13   |    8.52   |    --
             | 16 |     7.9    |     --    |     --    |    --
             | 17 |     --     |    3.81   |     --    |    --
             | 18 |     8.2    |     --    |    8.62   |    --
             | 19 |     --     |    3.43   |     --    |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Film dried  |           |           |Oily at end of
                  |up nicely   |           |           |1st and 2d
                  |during 3d   |           |           |days. Slightly
                  |day, but re-|           |           |tacky, end of
                  |mained      |           |           |10th day.
                  |slightly    |           |           |
                  |soft.       |           |           |
  ----------------+------------+-----------+-----------+--------------

  TABLE VIII.--(_a_) CORN OIL    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.0574   |   0.5858  |  0.4981   |  0.3300
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     1.9    |[11]0.22   |     1.22  |   4.63
             |  2 |     4.2    |    7.03   |     5.86  |   7.27
             |  3 |     4.6    |    8.79   |     7.27  |   7.14
             |  4 |     4.8    |    7.43   |[12]11.35  |   6.99
             |  5 |     7.5    |    7.17   |    11.35  |   6.69
             |  6 |     7.1    |     --    |      --   |   6.93
             |  7 |     --     |    5.85   |    11.37  |    --
             |  8 |     7.1    |    6.02   |      --   |   6.84
             |  9 |     --     |    5.84   |     6.26  |    --
  Percentage | 10 |     7.1    |    5.58   |      --   |   5.11
  Increase   | 11 |     --     |     --    |     4.97  |    --
  in Weight, | 12 |     7.2    |    5.38   |      --   |   5.17
  in Days.   | 13 |     --     |     --    |     5.62  |    --
             | 14 |     7.1    |     --    |      --   |   5.38
             | 15 |     --     |    4.78   |     5.34  |    --
             | 16 |     7.0    |     --    |      --   |   5.17
             | 17 |     --     |    4.15   |      --   |    --
             | 18 |     6.9    |     --    |     5.34  |    --
             | 19 |     --     |    3.63   |      --   |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Film soft   |           |           |
                  |and sticky  |           |           |
                  |throughout  |           |           |
                  |test. Very  |           |           |
                  |soapy in    |           |           |
                  |appearance. |           |           |
  ----------------+------------+-----------+-----------+--------------

  [11] Lost in weight throughout test.

  [12] Moth got in.

  (_b_) CORN OIL           20 PER CENT.
        RAW LINSEED OIL    80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |  0.1664    |   0.5469  |  0.3716   |  0.1711
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    7.5     |   13.01   |  13.81    |  11.87
             |  2 |    8.4     |   12.41   |  12.92    |  11.69
             |  3 |    8.6     |     --    |  12.16    |   9.78
             |  4 |   10.2     |   11.13   |  11.71    |   8.33
             |  5 |   10.4     |   11.52   |  11.11    |   8.50
             |  6 |   10.6     |     --    |    --     |   8.62
             |  7 |    --      |   11.22   |   9.23    |    --
             |  8 |   10.5     |   10.98   |    --     |   9.61
             |  9 |    --      |   10.38   |   8.29    |    --
  Percentage | 10 |   10.3     |    9.64   |    --     |   8.16
  Increase   | 11 |    --      |     --    |   7.24    |    --
  in Weight, | 12 |   10.3     |    9.07   |    --     |   7.00
  in Days.   | 13 |    --      |     --    |   8.42    |    --
             | 14 |   10.3     |     --    |    --     |   8.28
             | 15 |    --      |    8.38   |   8.26    |    --
             | 16 |   10.2     |     --    |    --     |    --
             | 17 |    --      |    8.77   |    --     |    --
             | 18 |   10.0     |     --    |   7.94    |    --
             | 19 |    --      |     --    |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Film tacky  |           |           |Tacky, end of
                  |at end of   |           |           |1st and 2d
                  |test.       |           |           |days. Dry, end
                  |            |           |           |10th day.
  ----------------+------------+-----------+-----------+--------------

  TABLE IX.--(_a_) COTTON SEED OIL  100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |  0.2026    |   0.7247  |  0.4135   |  0.3583
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    4.5     |    8.03   |   7.04    |   6.67
             |  2 |    4.8     |    7.48   |   7.16    |   5.61
             |  3 |    4.8     |    6.68   |   6.62    |   4.85
             |  4 |    5.1     |    6.00   |   6.24    |   4.65
             |  5 |    8.6     |    5.65   |   5.78    |   4.37
             |  6 |    8.7     |     --    |    --     |   4.71
             |  7 |    --      |    4.85   |   3.72    |    --
             |  8 |    8.1     |    5.09   |    --     |   4.57
             |  9 |    --      |    4.95   |   2.08    |    --
  Percentage | 10 |    7.9     |    4.80   |    --     |   2.97
  Increase   | 11 |    --      |     --    |   1.72    |    --
  in Weight, | 12 |    8.0     |     --    |    --     |   3.11
  in Days.   | 13 |    --      |     --    |   2.52    |    --
             | 14 |    8.0     |     --    |    --     |   3.39
             | 15 |    --      |     --    |   2.35    |    --
             | 16 |    8.1     |     --    |    --     |   3.39
             | 17 |    --      |     --    |    --     |    --
             | 18 |    8.0     |     --    |   2.32    |    --
             | 19 |    --      |     --    |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Film showed |           |           |Slightly
                  |very little |           |           |tacky, end
                  |hardening   |           |           |10th and 38th
                  |and remained|           |           |days.
                  |soft and    |           |           |
                  |tacky.      |           |           |
  ----------------+------------+-----------+-----------+--------------

  (_b_) COTTON SEED OIL    20 PER CENT.
        RAW LINSEED OIL    80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |  0.1516    |   0.9498  |  0.6160   |  0.2553
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    8.5     |   11.00   |   10.94   |  11.83
             |  2 |    8.7     |   11.15   |   10.81   |  11.83
             |  3 |    9.1     |   10.58   |   10.51   |  10.15
             |  4 |   10.8     |   10.17   |   10.37   |   9.29
             |  5 |   11.9     |    9.82   |    9.87   |   9.29
             |  6 |   11.8     |     --    |     --    |   9.45
             |  7 |    --      |    9.02   |    8.93   |    --
             |  8 |   11.9     |    9.42   |     --    |  10.00
             |  9 |    --      |    9.35   |    8.90   |    --
  Percentage | 10 |   11.9     |    9.27   |     --    |   8.95
  Increase   | 11 |    --      |     --    |    8.70   |    --
  in Weight, | 12 |   11.8     |    9.32   |     --    |   8.06
  in Days.   | 13 |    --      |     --    |    9.29   |    --
             | 14 |   11.8     |     --    |     --    |   8.61
             | 15 |    --      |    8.81   |    9.63   |    --
             | 16 |   11.8     |     --    |     --    |    --
             | 17 |    --      |    8.24   |     --    |    --
             | 18 |   10.7     |     --    |    8.47   |    --
             | 19 |    --      |    7.92   |     --    |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Fair drying |           |           |Tacky on 1st
                  |observed at |           |           |and 2d days.
                  |end of 4th  |           |           |Dry on 10th
                  |day. Film   |           |           |day.
                  |slightly    |           |           |
                  |tacky at end|           |           |
                  |of test.    |           |           |
  ----------------+------------+-----------+-----------+--------------

  TABLE X.--(_a_) SUN FLOWER OIL    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1414   |   0.6292  |  0.5837   |  0.2540
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     6.3    |    9.69   |   7.85    |   8.39
             |  2 |     8.2    |    9.42   |   7.73    |   6.94
             |  3 |    11.5    |    7.99   |   7.45    |   6.21
             |  4 |    11.6    |    7.43   |   7.02    |   6.13
             |  5 |    11.5    |    7.04   |   6.36    |   5.81
             |  6 |    11.5    |     --    |    --     |   6.01
             |  7 |     --     |    6.12   |   5.16    |    --
             |  8 |    11.3    |    6.45   |    --     |   6.09
             |  9 |     --     |    6.12   |   4.57    |    --
  Percentage | 10 |    11.3    |    5.92   |    --     |   4.81
  Increase   | 11 |     --     |     --    |   4.20    |    --
  in Weight, | 12 |    11.3    |    5.69   |    --     |   4.73
  in Days.   | 13 |     --     |     --    |   4.54    |    --
             | 14 |    11.3    |     --    |    --     |   4.81
             | 15 |     --     |    5.24   |   4.61    |    --
             | 16 |    11.2    |     --    |    --     |   5.01
             | 17 |     --     |    4.57   |    --     |    --
             | 18 |    11.0    |     --    |   4.30    |    --
             | 19 |     --     |    4.26   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Film fairly |           |           |Sticky, end
                  |firm, end of|           |           |1st day;
                  |3d day.     |           |           |tacky, end 2d
                  |            |           |           |day; slightly
                  |            |           |           |tacky, end
                  |            |           |           |10th day.
  ----------------+------------+-----------+-----------+--------------

  TABLE X.--(_b_) SUN FLOWER OIL    20 PER CENT.
                  RAW LINSEED OIL   80 PER CENT.
  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1600   |   0.5030  |  0.4470   |  0.2261
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     9.5    |   14.21   |   12.62   |  11.54
             |  2 |    11.0    |   14.21   |   12.02   |  11.85
             |  3 |    11.1    |   12.66   |   11.48   |   9.92
             |  4 |    11.3    |   14.01   |   11.65   |   9.13
             |  5 |    11.4    |   11.59   |   10.25   |   8.95
             |  6 |    10.9    |     --    |     --    |   9.04
             |  7 |     --     |   10.24   |    8.14   |    --
             |  8 |    10.8    |   10.63   |     --    |   9.52
             |  9 |     --     |   10.34   |    6.26   |    --
  Percentage | 10 |    10.8    |   10.34   |     --    |   8.55
  Increase   | 11 |     --     |     --    |    5.54   |    --
  in Weight, | 12 |    10.8    |   10.27   |     --    |   7.67
  in Days.   | 13 |     --     |     --    |    6.22   |    --
             | 14 |    10.6    |     --    |     --    |   8.20
             | 15 |     --     |   11.33   |    5.82   |    --
             | 16 |    10.6    |     --    |     --    |    --
             | 17 |     --     |   10.73   |     --    |    --
             | 18 |    10.9    |     --    |    5.35   |    --
             | 19 |     --     |   10.30   |     --    |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Good firm,  |           |           |Dry on 1st, 2d
                  |glossy film |           |           |and 10th days.
                  |shown at end|           |           |
                  |of 2d day.  |           |           |
  ----------------+------------+-----------+-----------+--------------

  TABLE XI.--(_a_) MENHADEN OIL    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1944   |   0.5282  |  0.7005   |  0.3150
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     7.7    |   12.47   |  10.79    |  11.27
             |  2 |     8.1    |   12.17   |  10.98    |  10.16
             |  3 |     8.9    |   11.70   |  10.85    |   9.72
             |  4 |    10.1    |   11.47   |  10.90    |   9.97
             |  5 |     9.8    |   11.13   |  10.57    |   9.94
             |  6 |     9.8    |     --    |    --     |  10.27
             |  7 |     --     |   10.28   |   9.27    |    --
             |  8 |     9.8    |   11.20   |    --     |  10.36
             |  9 |     --     |   11.15   |   8.48    |    --
  Percentage | 10 |     9.8    |   11.02   |    --     |   8.80
  Increase   | 11 |     --     |     --    |   8.27    |    --
  in Weight, | 12 |     9.8    |   11.37   |    --     |   9.22
  in Days.   | 13 |     --     |     --    |   8.91    |    --
             | 14 |     9.6    |     --    |    --     |   9.40
             | 15 |     --     |   10.85   |   8.75    |    --
             | 16 |     9.6    |     --    |    --     |   9.31
             | 17 |     --     |   10.34   |    --     |    --
             | 18 |     9.6    |     --    |   9.21    |    --
             | 19 |     --     |    9.90   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Good drying |           |           |Sticky, end
                  |during 2d   |           |           |1st day.
                  |day. Fairly |           |           |Slightly
                  |firm film.  |           |           |sticky, end 2d
                  |            |           |           |and 10th days.
  ----------------+------------+-----------+-----------+--------------

  (_b_) MENHADEN OIL    20 PER CENT.
        RAW LINSEED OIL 80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.2448   |   0.4959  |  0.4201   |  0.2456
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     8.5    |   14.11   |  13.19    |  10.99
             |  2 |    10.4    |   13.47   |  12.88    |  11.28
             |  3 |    12.2    |   12.68   |  12.23    |   9.56
             |  4 |    12.9    |   12.04   |  11.81    |   8.90
             |  5 |    12.9    |   11.59   |  11.17    |   8.72
             |  6 |    12.9    |     --    |    --     |   8.72
             |  7 |     --     |   10.44   |   9.50    |    --
             |  8 |    12.9    |   11.09   |    --     |   9.34
             |  9 |     --     |   11.04   |   8.48    |    --
  Percentage | 10 |    12.9    |   10.74   |    --     |   8.40
  Increase   | 11 |     --     |     --    |   7.77    |    --
  in Weight, | 12 |    12.9    |   10.90   |    --     |   7.37
  in Days.   | 13 |     --     |     --    |   8.33    |    --
             | 14 |    12.8    |     --    |    --     |   8.11
             | 15 |     --     |   10.18   |   8.24    |    --
             | 16 |    12.7    |     --    |    --     |    --
             | 17 |     --     |    9.48   |    --     |    --
             | 18 |    12.9    |     --    |   8.12    |    --
             | 19 |     --     |    8.93   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Good firm,  |           |           |Nearly dry on
                  |elastic film|           |           |1st and 2d
                  |shown after |           |           |days.
                  |2d day.     |           |           |
  ----------------+------------+-----------+-----------+--------------

  TABLE XII.--(_a_) RAW CHINESE WOOD OIL    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.2266   |   0.5545  |  0.4933   |  0.4036
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     4.1    |     --    |   0.59    |   0.54
             |  2 |    11.2    |     --    |   2.09    |   2.80
             |  3 |    14.9    |   11.02   |   5.13    |   5.10
             |  4 |    14.4    |   11.53   |   7.56    |   6.00
             |  5 |    14.4    |   11.03   |   8.68    |   6.27
             |  6 |    14.2    |     --    |    --     |   7.09
             |  7 |     --     |   10.53   |  10.11    |    --
             |  8 |    14.2    |   10.74   |    --     |   8.39
             |  9 |     --     |   10.47   |   9.65    |    --
  Percentage | 10 |    14.2    |   10.27   |    --     |   8.01
  Increase   | 11 |     --     |     --    |   9.43    |    --
  in Weight, | 12 |    14.2    |   10.22   |    --     |   8.55
  in Days.   | 13 |     --     |     --    |   9.77    |    --
             | 14 |    14.2    |     --    |    --     |   9.13
             | 15 |     --     |    9.80   |   9.73    |    --
             | 16 |    14.2    |     --    |    --     |   9.27
             | 17 |     --     |    9.25   |    --     |    --
             | 18 |    14.5    |     --    |   9.33    |    --
             | 19 |     --     |    8.86   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Film crys-  |           |           |Sticky, end of
                  |tallized and|           |           |1st and 2d
                  |remained    |           |           |days; dry but
                  |soft until  |           |           |drawn, end of
                  |3d day. Hard|           |           |10th day.
                  |but opaque  |           |           |
                  |film shown  |           |           |
                  |after 4th   |           |           |
                  |day.        |           |           |
  ----------------+------------+-----------+-----------+--------------

  (_b_) RAW CHINESE WOOD OIL    20 PER CENT.
        RAW LINSEED OIL         80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.2087   |   0.2967  |  0.3683   |  0.2285
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     9.0    |   14.46   |  14.37    |  11.99
             |  2 |    12.1    |   13.11   |  13.66    |  11.90
             |  3 |    12.9    |   11.72   |  13.11    |  10.14
             |  4 |    12.8    |   10.68   |  12.41    |   9.30
             |  5 |    12.8    |    9.77   |  11.78    |   9.08
             |  6 |    12.8    |     --    |    --     |   9.30
             |  7 |     --     |    8.66   |  10.51    |    --
             |  8 |    12.7    |    8.86   |    --     |   9.70
             |  9 |     --     |    8.80   |   8.72    |    --
  Percentage | 10 |    12.6    |    8.49   |    --     |   8.90
  Increase   | 11 |     --     |     --    |   7.0     |    --
  in Weight, | 12 |    12.6    |    8.15   |    --     |   7.34
  in Days.   | 13 |     --     |     --    |   8.82    |    --
             | 14 |    12.5    |     --    |    --     |   7.78
             | 15 |     --     |    8.05   |   8.39    |    --
             | 16 |    12.5    |     --    |    --     |    --
             | 17 |     --     |    7.41   |    --     |    --
             | 18 |    12.7    |     --    |   7.98    |    --
             | 19 |     --     |    7.04   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Clear and   |           |           |Dry at end of
                  |firm film   |           |           |1st day.
                  |shown after |           |           |
                  |3d day.     |           |           |
  ----------------+------------+-----------+-----------+--------------

  TABLE XIII.--(_a_) CHINESE WOOD OIL (TREATED)    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1678   |   0.4159  |  0.2934   |  0.3937
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |[13]38.0    |[13]19.06  |[13]0.92   |   3.53
             |  2 |[13]30.0    |[13]20.16  |[13]0.41   |   3.58
             |  3 |[13]28.0    |[13]20.47  |    0.72   |   3.25
             |  4 |[13]28.0    |[13]20.47  |    0.79   |   3.25
             |  5 |[13]28.0    |[13]20.80  |    0.13   |   3.33
             |  6 |[13]28.0    |     --    |     --    |   2.93
             |  7 |     --     |[13]21.09  |    0.22   |    --
             |  8 |[13]28.0    |[13]20.87  |     --    |   2.55
             |  9 |     --     |[13]20.98  |    0.46   |    --
  Percentage | 10 |    27.5    |[13]20.78  |     --    |   3.40
  Increase   | 11 |     --     |     --    |    0.44   |    --
  in Weight, | 12 |[13]26.0    |[13]20.70  |     --    |   3.23
  in Days.   | 13 |     --     |     --    |    0.43   |    --
             | 14 |[13]26.0    |     --    |     --    |   2.61
             | 15 |     --     |[13]20.97  |    0.42   |    --
             | 16 |[13]26.0    |     --    |     --    |   2.48
             | 17 |     --     |[13]21.22  |     --    |    --
             | 18 |[13]26.2    |     --    |    0.43   |    --
             | 19 |     --     |[13]21.11  |     --    |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Loss ob-    |           |           |Dry at end of
                  |served due  |           |           |1st day.
                  |to presence |           |           |
                  |of vola-    |           |           |
                  |tiles. Firm,|           |           |
                  |clear film  |           |           |
                  |shown at end|           |           |
                  |of 1st day. |           |           |
  ----------------+------------+-----------+-----------+--------------

  [13] Lost in weight throughout test.

  TABLE XIII.--(_b_) CHINESE WOOD OIL (TREATED)    20 PER CENT.
                     RAW LINSEED OIL               80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1638   |   0.6572  |  0.4892   |  0.2644
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |     8.4    |    9.25   |   8.93    |   3.21
             |  2 |     9.4    |    8.07   |   8.71    |   3.48
             |  3 |     9.8    |    7.36   |   8.44    |   2.15
             |  4 |     9.7    |    6.75   |   8.16    |   1.58
             |  5 |     9.9    |    6.25   |   7.95    |   1.56
             |  6 |     9.9    |     --    |    --     |   1.77
             |  7 |      --    |    5.49   |   6.75    |    --
             |  8 |    10.0    |    5.87   |    --     |   2.30
             |  9 |      --    |    5.70   |   5.99    |    --
  Percentage | 10 |     9.6    |    5.67   |    --     |   1.62
  Increase   | 11 |      --    |     --    |   5.50    |    --
  in Weight, | 12 |     9.5    |    4.37   |    --     |   0.86
  in Days.   | 13 |      --    |     --    |   6.40    |    --
             | 14 |     9.5    |     --    |    --     |   1.50
             | 15 |      --    |    5.15   |   6.01    |    --
             | 16 |     9.5    |     --    |    --     |    --
             | 17 |      --    |    4.69   |    --     |    --
             | 18 |     9.6    |     --    |   5.87    |    --
             | 19 |      --    |    4.17   |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Clear and   |           |           |Dry at end of
                  |hard film   |           |           |1st day.
                  |shown during|           |           |
                  |2d day.     |           |           |
  ----------------+------------+-----------+-----------+---------------

  TABLE XIV.--(_a_) 20 PER CENT. DRY ROSIN IN 80 PER CENT. LINSEED OIL
                    100 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.2030   |     --    |  0.5185   |  0.2554
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    12.0    |     --    |   3.76    |   1.80
             |  2 |    14.1    |     --    |   8.76    |  11.78
             |  3 |    14.8    |     --    |   9.20    |  12.17
             |  4 |    14.2    |     --    |   9.20    |  12.29
             |  5 |    14.5    |     --    |   8.49    |  12.02
             |  6 |    14.0    |     --    |    --     |  12.49
             |  7 |     --     |     --    |   9.07    |    --
             |  8 |    14.1    |     --    |    --     |  13.15
             |  9 |     --     |     --    |   9.01    |    --
  Percentage | 10 |    14.1    |     --    |    --     |  11.85
  Increase   | 11 |     --     |     --    |   9.09    |    --
  in Weight, | 12 |    14.0    |     --    |    --     |  11.78
  in Days.   | 13 |     --     |     --    |  10.50    |    --
             | 14 |    14.0    |     --    |    --     |  12.69
             | 15 |     --     |     --    |  10.16    |    --
             | 16 |    14.0    |     --    |    --     |  12.83
             | 17 |     --     |     --    |    --     |    --
             | 18 |    14.1    |     --    |  10.18    |    --
             | 19 |     --     |     --    |    --     |    --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Rapid drying|           |           |Oily, end 1st
                  |observed.   |           |           |and 2d days;
                  |Hard film   |           |           |slightly
                  |shown during|           |           |tacky, end
                  |2d day.     |           |           |10th day.
  ----------------+------------+-----------+-----------+---------------

  (_b_) 20 PER CENT. DRY ROSIN IN 80 PER CENT. LINSEED OIL  20 PER CENT.
        RAW LINSEED OIL                                     80 PER CENT.

  ----------------+------------+-----------+-----------+--------------
   Observer.      |  Gardner   |   Sabin   |  Pickard  | { Rogers }
                  |            |           |           | { North  }
  ----------------+------------+-----------+-----------+--------------
  Wt. of Oil for  |   0.1500   |   0.7105  |  0.4568   |     --
  Test, grams     |            |           |           |
  -----------+----+------------+-----------+-----------+--------------
             |  1 |    10.9    |   14.19   |  12.86    |     --
             |  2 |    13.5    |   13.17   |  12.73    |     --
             |  3 |    13.6    |   11.84   |  12.13    |     --
             |  4 |    13.0    |   11.46   |  12.02    |     --
             |  5 |    13.0    |   10.87   |  11.30    |     --
             |  6 |    13.0    |     --    |    --     |     --
             |  7 |     --     |    9.80   |  10.95    |     --
             |  8 |    13.1    |   10.33   |    --     |     --
             |  9 |     --     |   10.40   |  11.21    |     --
  Percentage | 10 |    13.1    |   10.04   |    --     |     --
  Increase   | 11 |     --     |     --    |  10.53    |     --
  in Weight, | 12 |    13.0    |   10.35   |    --     |     --
  in Days.   | 13 |     --     |     --    |  11.21    |     --
             | 14 |    12.9    |     --    |    --     |     --
             | 15 |     --     |    9.64   |  10.88    |     --
             | 16 |    13.0    |     --    |    --     |     --
             | 17 |     --     |    8.98   |    --     |     --
             | 18 |    13.2    |     --    |  11.43    |     --
             | 19 |     --     |    8.62   |    --     |     --
  -----------+----+------------+-----------+-----------+--------------
  Remarks.        |Clear, hard |           |           |
                  |film after  |           |           |
                  |2d day.     |           |           |
  ----------------+------------+-----------+-----------+--------------

  TABLE XV.--(_a_) RAW LINSEED OIL    100 PER CENT.[14]

  ----------------+-----------+-----------
   Observer.      |   Sabin   |  Pickard
                  |           |
  ----------------+-----------+-----------
  Wt. of Oil for  |   0.5274  |  0.5326
  Test, grams     |           |
  -----------+----+-----------+-----------
             |  1 |    0.26   |  12.42
             |  2 |    0.51   |  12.39
             |  3 |    0.11   |  11.88
             |  4 |    2.35   |  11.83
             |  5 |    9.14   |  11.08
             |  6 |     --    |    --
             |  7 |   14.48   |  10.29
             |  8 |   14.48   |    --
             |  9 |   14.18   |   9.56
  Percentage | 10 |   13.86   |    --
  Increase   | 11 |     --    |   9.85
  in Weight, | 12 |   13.00   |    --
  in Days.   | 13 |     --    |  10.30
             | 14 |     --    |    --
             | 15 |   12.23   |  10.12
             | 16 |     --    |    --
             | 17 |   11.66   |    --
             | 18 |     --    |  10.78
             | 19 |   11.07   |    --
  -----------+----+-----------+-----------
  Remarks.        |           |
  ----------------+-----------+-----------

  [14] The test of this oil was made without the addition of 5 per cent.
       of drier, the quantity used in all the other tests.

  (_b_) DRIER    100 PER CENT.

  ----------------+--------------
   Observer.      | { Rogers }
                  | { North  }
  ----------------+--------------
  Wt. of Oil for  |  0.3445
  Test, grams     |
  -----------+----+--------------
             |  1 |  48.95
             |  2 |  48.53
             |  3 |  48.68
             |  4 |  48.68
             |  5 |  48.48
             |  6 |  48.26
             |  7 |    --
             |  8 |  48.43
             |  9 |    --
  Percentage | 10 |  48.89
  Increase   | 11 |    --
  in Weight, | 12 |  48.22
  in Days.   | 13 |    --
             | 14 |  48.22
             | 15 |    --
             | 16 |    --
             | 17 |    --
             | 18 |    --
             | 19 |    --
  -----------+----+--------------
  Remarks.        | Dry at end of
                  | 1st day.
  ----------------+--------------



CHAPTER III

PAINT PIGMENTS AND THEIR PROPERTIES


For the student of paint technology, who is not already acquainted with
the chemistry and physics of the various raw pigments which are largely
used in the manufacture of paints, the writer advises a careful reading
of this chapter, in which the matter has been condensed as much as
possible. In order to more thoroughly acquaint the reader with the
physical constitution of the pigments under consideration, there has
been included photomicrographs, which show to advantage the structure of
each.[15]

  [15] The author gratefully acknowledges the assistance of Dr. J. A.
       Schaeffer in the preparation of the photomicrographs shown in
       this chapter.

[Illustration: By Polarized Light

By Transmitted Light

Basic Carbonate-White Lead]

=Basic Carbonate-White Lead.= This pigment is made by stacking clay pots
containing dilute acetic acid and lead buckles, in tiers, and covering
them with tan bark. Fermentation of the tan bark, with subsequent
formation of carbon dioxide acting on the acetate of lead formed within
the pots, produces basic carbonate of lead. After complete corrosion,
the white lead is ground, floated, and dried. Corroded white lead has a
specific gravity of 6.8 and contains about 85% lead oxide and 15% of
carbon dioxide and water. Its opaque nature and excellent body renders
it extremely valuable as a constituent of paints. Checking and chalking
progress rapidly when the pigment is used alone. The various sized
particles, both large and small, resulting from the corrosion process,
are prominently shown in the photomicrograph.

[Illustration: Crystals of Cerussite in Old Dutch Process White Lead.
(Greatly magnified)]

[Illustration: White Lead (Quick Process)]

On account of its alkaline nature, this pigment acts upon the
saponifiable oil in which it is ground, forming lead soaps which
accelerate chalking of white lead--the greatest evil attending its use.
Solubility in carbonic acid of the atmosphere and decay in the presence
of sodium chloride may be active causes of the rapid chalking of this
pigment at the seashore. Checking in some climates appears to proceed
rapidly on white lead paints, in a deep hexagonal form, leaving a series
of rough crests and cracks. This checking is secondary to the chalking
which takes place.

[Illustration: Corrosion cylinders used for making Quick Process White
Lead]

[Illustration: Lead Melting Pots]

=White Lead (Quick Process).= By acting on atomized metallic lead,
contained within large revolving wooden cylinders, with dilute acetic
acid and carbon dioxide, the quick-process white lead is produced. Its
value is equal to the Dutch-process white lead, and it is considered by
some as possessing greater spreading value.

[Illustration: Sheet iron box luted at bottom with water. Atomized lead,
blown into box with steam, falls to bottom and becomes hydrated (Mild
Process)]

[Illustration: _Photographs courtesy of Stowe Neal_

View of agitation tanks for making Mild Process Lead]

[Illustration: Steam Jected Pans for Drying White Lead]

=White Lead (Mild Process).= The Mild Process of manufacturing white
lead consists of first melting the pig lead and converting it into the
finest kind of lead powder, then mixing thoroughly with air and water.
The lead takes up water and oxygen and forms a basic hydroxide of lead.
Carbon dioxide gas is next pumped slowly through the cylinders which
contain the basic hydroxide of lead. The result is basic carbonate of
lead--the dry white lead of commerce. The process is called "Mild"
because it is the mildest process possible for the manufacture of white
lead. It is the only method in practical operation which does not
require the use of acids, alkalis or other chemicals, every trace of
which should be removed from the finished product by expensive purifying
processes. The failure of such washing and purifying means a product of
inferior quality, which necessarily reduces the durability of any paint
in which it is used.

=Basic Sulphate-White Lead (Sublimed White Lead).= By the action of the
oxygen of the air on the fume produced by the roasting and subsequent
volatilization of galena, this fine, white, amorphous pigment is made.
On analysis, its composition shows approximately 75% of lead sulphate,
20% of lead oxide, and 5% of zinc oxide. It has a specific gravity of
6.2. Possessed of extreme stability, it finds wide use as a constituent
of paints and as a base for tinting colors. The photomicrograph of this
pigment shows its extremely fine, amorphous nature with complete absence
of crystals. In fineness it closely approaches zinc oxide. On account of
its non-poisonous properties it is replacing corroded lead in many
places. Unified paints containing sublimed white lead are of great
value, showing upon long exposure very little decay.

[Illustration: View of Furnace for Making Sublimed White Lead]

[Illustration: View of Goosenecks Used for Collecting Sublimed White
Lead Fume]

[Illustration: Bag Room Where Sublimed White Lead is Deposited

_Photographs courtesy of Picher Lead Co._]

[Illustration: Sublimed White Lead]

[Illustration: View of largest Zinc Oxide Works in America, at Hazards,
Pa.]


=Sublimed Blue Lead.= Sublimed blue lead is made by burning coarsely
broken lumps of galena, admixed with bituminous coal, in a special form
of furnace. The fumes which are volatilized from this mixture are very
complex in their chemical make-up, and in color are white, blue, and
black. After being drawn through the cooling pipes by the suction of
huge fans, whereby the fumes are cooled, the pigment is deposited in
bags. This pigment is bluish black in color, and has been highly
recommended for use on iron and steel. Its composition runs
approximately as follows:

  Lead sulphate      50%
  Lead oxide         35%
  Lead sulphide       5%
  Lead sulphite       5%
  Zinc oxide          2%
  Carbon              3%

[Illustration: View of Zinc Oxide Furnaces]

[Illustration: _Photographs courtesy Geo. B. Heckel and N. J. Zinc Co._

View of Zinc Oxide Fume Pipes with electrically driven Suction Fans]

The color of the pigment is largely due to the carbon and the lead
sulphide. Its specific gravity is 6.4, and it grinds in 10% of oil to a
stiff paste, 100 lbs. of which may be thinned with about 26 lbs. of oil
to working consistency. Paint manufacturers use it in mixture with iron
oxide and other pigments for the production of paints for metal
surfaces. Wood and others have found it of great value for this purpose.
It has a tendency to chalk, but this may be overcome by admixture with
other pigments such as zinc oxide and iron oxide. Lane has found it to
be very durable when admixed with lampblack.

[Illustration: View of Bag Room receiving Zinc Oxide]

=Zinc Oxide.= This extremely white and fine pigment is prepared by the
roasting and sublimation of franklinite, zincite, and other zinc-bearing
ores largely found in New Jersey. Its purity approaches in most
instances 99.5 or more. It has a specific gravity of 5.2. On account of
its stability, whiteness, and opacity, it is invaluable as a pigment
when a constituent in a combination formula. Its extreme hardness
renders it less resistant to temperature changes, when used alone. Under
the microscope the fineness and structure of the particles are clearly
evident. The French-process zinc oxide produced in America by the
sublimation and oxidation of spelter is the purest made, and superior to
imported grades which often contain ultramarine blue as a whitening
agent.

[Illustration: Zinc Oxide]

[Illustration: Zinc Lead White]

[Illustration: Zinc Lead. By transmitted light

(_The Pigment shows black_)]

[Illustration: Lithopone]

[Illustration: Magnesium Silicate (Asbestine)]

=Zinc Lead White.= This extremely fine pigment, consisting of about
equal parts of zinc oxide and lead sulphate, results from the reduction,
volatilization and subsequent oxidation of sulphur-bearing lead and zinc
ores. It has a specific gravity of 4.4. Its slightly yellowish tint bars
it from being used alone very extensively, but when mixed with white
lead, zinc oxide and inert pigments, or used as a base for colored
paints, it is of considerable value. The magnification of the particles
shows the peculiar way in which the pigment agglomerates, and the
characteristics of a fine, uniform pigment.

[Illustration: Asbestine Mine at Easton, Pa.]

[Illustration: American Barytes. Transmitted light

(_The Pigment shows black_)]

[Illustration: German Barytes. Mag. 250 Diam.

(_The Pigment shows white_)]

=Lithopone.= Lithopone, probably the whitest of pigments, results from
the double decomposition of zinc sulphate and barium sulphide, thereby
forming a molecular combination of zinc sulphide and barium sulphate.
The peculiar property which it possesses, of darkening under the actinic
rays of the sun, makes it essential that it be combined with other, more
stable pigments to prolong its life when exposed to weather. Lithopone
contains approximately 70% barium sulphate, 25 to 28% zinc sulphide, and
as high as 5% of zinc oxide. Its specific gravity is about 4.25. It is
excellently suited for interior use in the manufacture of enamels and
wall finishes. When properly mixed with other pigments, such as zinc
oxide and calcium carbonate, fair results are obtained as a pigment for
outside work. Lead pigments are never used with lithopone, as lead
sulphide results, giving a black appearance. Its characteristic
flocculent, non-crystalline nature is plainly evident when examined
under the microscope.

[Illustration: By Polarized Light

By Transmitted Light

Barium Sulphate (Barytes)]

=Magnesium Silicate (Asbestine and Talcose).= This pigment comes in two
forms: as asbestine and as talcose (talc, etc.). The former is very
fibrous in nature and is a very stable pigment to use in the manufacture
of paint, on account of its inert nature and tendency to hold up heavier
pigments, and prevent settling. It also has the property of
strengthening a paint coat in which it is used. The talcose variety is
very tabular in form. Both varieties are transparent in oil, and very
inert. They have a gravity of about 2.7 and grind in about 32% of oil.

[Illustration: Barium Carbonate. Mag. 250 Diam.

(_The Pigment shows white_)]

[Illustration: Barium Sulphate (Blanc Fixe)]

[Illustration: Calcium Carbonate (Whiting)]

[Illustration: Calcium Carbonate. By transmitted light

(_The Pigment shows black_)]

[Illustration: Calcium Sulphate. By transmitted light

(_The Pigment shows black_)]

[Illustration: Calcium Sulfate]

[Illustration: Calcium Sulphate (Gypsum)]

[Illustration: Silica (Silex)]

[Illustration: Silex. Mag. 250 Diam.

(_The Pigment shows white_)]

[Illustration: China Clay. By transmitted light

(_The Pigment shows black_)]

=Barium Sulphate (Barytes).= By grinding the crude ore, treating with
acid to remove the iron, and finally washing, floating, and drying,
there is produced the commercial form of this valuable pigment. It is
used in large quantity as a base upon which to precipitate colors, and
also together with other white pigments in the manufacture of
ready-mixed paints. It renders the paint coating more resistant to
abrasion, and gives to the paint certain very important brushing
qualities. It is a very stable pigment, not being materially affected by
either acid or alkali, and can be used with the most delicate colors. In
oil it is transparent and must be mixed with opaque pigments when used
in ready-mixed paints. It is generally used with lighter pigments, such
as asbestine, in order to prevent settling. Under the microscope, both
by polarized and transmitted light, the sharp angles of the particles
appear distinctly, with no tendency to mass into a compact form.
Although transparent in oil, it is valuable in moderate percentage in a
ready-mixed paint.

=Barium Sulphate (Blanc Fixe).= Blanc fixe is the precipitated form of
barium sulphate, resulting from the action of soluble barium salts on
soluble sulphates. The specific gravity (4.2) of this compound is lower
than that of barytes. Possessing greater opacity in oil, it is of more
value as a paint pigment for some purposes. It comes in for its greatest
use as a base on which to precipitate lake colors. The very fine
particles show a slight tendency to agglomerate.

=Calcium Carbonate (Whiting).= The natural form of calcium carbonate,
prepared from chalk, has a much higher specific gravity (2.74) than that
of the artificial form (2.5) prepared by the precipitation of calcium
carbonate. The latter, however, possesses greater hiding properties.
Both grades find a wide use in distemper work and in the manufacture of
putty. It is often used in small percentage in many ready-mixed paints.
The photomicrograph of the pigment shows the presence of many large
particles.

=Calcium Sulphate (Gypsum).= The mineral gypsum, consisting of calcium
sulphate and about 21% of water of combination, is sometimes used as a
paint pigment after grinding and dehydration. Being slightly soluble in
water it has a tendency to pass into solution when exposed to
atmospheric agencies. It lacks hiding power in oil. Its specific gravity
is 2.3. As in the case of all pigments prepared directly from mineral
substances, the many-sized and shaped particles appear clearly when
enlarged. Partially and wholly dehydrated forms of gypsum are also used
in paint.

=Silica (Silex.)= This white pigment possesses great tooth and spreading
properties. It is of use as a wood filler and as a constituent in
combination paints. It wears especially well when used in combination
with zinc oxide and white lead. Its purity often approaches 97%. The
particles when enlarged are seen to have sharp angles and are not
uniform in size, which accounts for its marked tooth and properties.

[Illustration: Aluminum Silicate (China Clay)]

[Illustration: Ochre]

[Illustration: Raw

Burnt

Sienna]

[Illustration: Raw

Burnt

Umber]

=Aluminum Silicate (China Clay).= China clay, or aluminum silicate, is a
permanent and valuable white pigment showing very little hiding power in
oil. It is found widely distributed in granitic formations. It is very
stable, with a gravity of 2.6. Particles are found in many shapes and
sizes, showing sharp and definite angles.

=Ochre.= Ochre is a hydrated ferric oxide permeating a clay base,
largely used as a tinting material. It has a specific gravity of about
3.5, and a decidedly golden yellow color. A good quality should contain
20% or over of iron oxide. The particles of this pigment are flocculent
and very uniform in appearance.

=Sienna.= Sienna, like umber, is essentially a silicate of iron and
alumina, containing manganic oxide. It contains, however, a lower
percentage of the latter than in the case of umbers. The photomicrograph
of the burnt variety shows clearly the fine condition of the pigment,
while large particles are shown in the raw variety.

=Umber.= Umber, another naturally occurring pigment, consists of iron
and aluminum silicates, containing varying proportions of manganic
oxide, its color and tone varying according to the percentage of the
latter. The raw variety is drab in color, which in burning changes to
reddish brown. A marked percentage of large-sized particles exist in
this pigment.

=Indian Red.= Indian red is the term applied to natural hematite ore
pigments and to those produced by the roasting of copperas (iron
sulphate). They generally contain 95% or more of iron oxide, with
varying percentages of silica. The pigment is heavier (specific gravity
5.2) than that of Metallic Brown. The crystalline, mineral-like
structure of the particles differ greatly from the amorphous particles
of Metallic Brown.

=Metallic Brown.= The natural hydrated iron oxide or carbonate as mined
largely in Pennsylvania, yields, when roasted, a sesquioxide of iron
known as Metallic Brown. It contains a high percentage of alumina and
silica, and has a characteristic brown color with a gravity of 3.1. It
finds wide application as a pigment for protective purposes. The
particles when enlarged show the usual appearance of a natural compound
which has been roasted and ground.

  ==========+=====+===========+==========+=============+=======+=========
  No. Name  |Iron |   Calc.   | Alumina  |  Insoluble  | Color |
            |Oxide|  Sulph.   |          |             |(Silica|
            +-----+-----------+(CaSO_{4})|(Al_{2}O_{3})|  and  |
            | FeO |Fe_{2}O_{3}|          |             | Sili- |
            |     |           |          |             | cates)|
  ----------+-----+-----------+----------+-------------+-------+---------
            |   % |      %    |     %    |      %      |    %  |
   0 Bright | 0.71|    96.52  |    --    |     --      |   .30 |Bright
     Red    |     |           |          |             |       |Scarlet
   1 Bright |  .71|    95.92  |    --    |     --      |   .30 |Scarlet
     Red    |     |           |          |             |       |Tone
   2 Indian |  .57|    96.00  |    .78   |    1.40     |   .90 |Indian
     Red    |     |           |          |             |       |Red,
            |     |           |          |             |       |Medium
            |     |           |          |             |       |Shade
   3 Indian | 0.29|    97.82  |    .85   |     --      |   .52 |Indian
     Red    |     |           |          |             |       |Red,
            |     |           |          |             |       |Dark
            |     |           |          |             |       |Shade
   4 Indian | 0.28|    95.72  |   1.21   |    1.26     |   .58 |Indian
     Red    |     |           |          |             |       |Red,
            |     |           |          |             |       |Light
            |     |           |          |             |       |Shade
   5 Persian| 4.53|    62.25  |   1.75   |     --      | 27.64 |Rich,
     Gulf   |     |           |          |             |       |Medium
     Mix    |     |           |          |             |       |Red
   7 Native | 0.85|    89.00  |    --    |    0.91     |  6.09 |Medium
     Red    |     |           |          |             |       |Red,
     Oxide  |     |           |          |             |       |Brownish
            |     |           |          |             |       |Tone
   8 Special| 0.57|    43.87  |  50.88   |    2.03     |  1.30 |Scarlet
     Red    |     |           |          |             |       |Tone
  10 Red    | 1.44|    60.25  |    .78   |    5.41     | 15.78 |Brownish-
     Oxide  |     |           |          |             |       |Red
  11 Vene-  |  .30|    34.08  |  52.60   |    2.20     |  3.39 |Bright
     tian   |     |           |          |             |       |Red-
     Red    |     |           |          |             |       |Brown
  12 B.     | 0.58|    67.68  |    --    |    2.48     |  1.97 |Dark Red
     Oxide  |     |           |          |             |       |Brown
  13 Vene-  | 0.29|    25.92  |  58.62   |    2.16     |  1.42 |Medium
     tian   |     |           |          |             |       |Red
     Red    |     |           |          |             |       |Tone
  14 Vene-  | 0.57|    35.36  |    .99   |   12.06     | 47.97 |Brown
     tian   |     |           |          |             |       |
     Red    |     |           |          |             |       |
  15 Metal- | 2.59|    64.00  |    .63   |    5.82     | 23.42 |Rich
     lic    |     |           |          |             |       |Brown
     Brown  |     |           |          |             |       |
  16 Crimson| 0.57|    66.24  |   1.77   |    3.60     | 25.63 |Rich
     Oxide  |     |           |          |             |       |Dark
            |     |           |          |             |       |Red
  17 Red    | 2.30|    80.39  |    .37   |     .03     |  9.63 |Medium
     Oxide  |     |           |          |             |       |Brown
  18 Red    | 0.57|    61.28  |    .97   |    2.68     | 15.94 |Light
     Oxide  |     |           |          |             |       |Choco-
            |     |           |          |             |       |late
            |     |           |          |             |       |Brown
  20 Red    | 7.78|    46.72  |   1.70   |    7.64     | 20.38 |Dark
     Oxide  |     |           |          |             |       |Reddish
            |     |           |          |             |       |Brown
  23 Special| 0.58|    72.48  |    --    |    8.80     |  4.48 |Deep
     French |     |           |          |             |       |Choco-
     Oxide  |     |           |          |             |       |late
            |     |           |          |             |       |Brown
  24 Mica-  | 2.02|    86.27  |    --    |    2.04     |  9.50 |Dark
     ceous  |     |           |          |             |       |Gray
     Black  |     |           |          |             |       |Tone
     Oxide  |     |           |          |             |       |
  25 Black  |33.12|    57.12  |    --    |    1.44     |   --  |Jet
     Oxide  |     |           |          |             |       |Black
  26 Red    | 0.57|    84.16  |   5.00   |    2.00     |   .63 |Deep
     Oxide  |     |           |          |             |       |Red
  27 Special| 0.57|    38.40  |  55.62   |    2.12     |  1.53 |Medium
     Red    |     |           |          |             |       |Red
  28 Oxide C|  -- |    30.40  |    .94   |   13.60     | 42.30 |Brown
  ==========+=====+===========+==========+=============+=======+=========

=Analysis of Iron Oxide Pigments.= Because of the great consideration
now being given to iron oxide paints, the writer secured a series of
oxides widely used in this country, and has determined the most
important constituents of each.

=Basic Lead Chromate (American Vermilion).= By boiling white lead with
chromate of soda and subsequently treating with small quantities of
sulphuric acid, American vermilion, or basic lead chromate, is prepared.
It contains 98% of lead compounds, frequently free chromates, and has a
gravity of 6.8. The particles appear granular and large, frequently
assuming a square structure.

=Red Lead.= By the continued oxidation of litharge in reverberatory
furnaces, red lead is produced as a brilliant red pigment with a
specific gravity of 8.7. The pigment particles appear to be of many
sizes, showing a slight tendency to form a compact mass.

=Paranitraniline Red.= Paranitraniline red, a very bright red material
largely used in tinting paints, is prepared by diazotizing
paranitraniline in hydrochloric acid by means of sodium nitrite in the
cold. This compound is rendered insoluble when precipitated directly on
barytes, by acting on it with an alkaline solution of beta naphthol. It
is the most stable and permanent bright red organic pigment which the
paint manufacturer uses. The particles of this pigment appear in various
sizes, due, no doubt, to a massing of the particles in the precipitation
process.

=Chrome Yellow.= The neutral chromate of lead, made from either the
nitrate or acetate of lead and chromate of soda, finds wide use as a
tinting pigment. When precipitated on a white pigment base, various
trade names are given to it. The microscope shows clearly the physical
character of this pigment.

=Zinc Chromate.= This pigment is made either from zinc salts and
bichromate of potash or zinc oxide heated with chrome salts, frequently
in the presence of acid. Like the rest of the chromate pigments, it is a
very slow-drying material, often requiring over a week to set up, unless
considerable drier is added. In spite of the impurities which it
carries, it has shown itself to be one of the most inhibitive pigments
known and has demonstrated its value in even small percentages in paints
for iron and steel. It dries to a hard adherent film that tends to
protect metal from corrosion.

[Illustration: Indian Red]

[Illustration: Metallic Brown]

[Illustration: Basic Lead Chromate (American Vermilion)]

[Illustration: Red Lead]

[Illustration: Paranitraniline]

[Illustration: Chrome Yellow]

=Prussian Blue.= On oxidizing the precipitate resulting from the
interaction of solutions of prussiate of potash and copperas (iron
sulphate), Prussian blue as used in the paint trade is prepared. It has
a specific gravity of 1.9. The pigment shows an amorphous structure, the
particles varying greatly in size.

=Ultramarine Blue.= This bright blue pigment is prepared by burning
silica, china clay, soda ash and sulphur in pots or furnaces. It has a
specific gravity of 2.4. It is of little value as a paint pigment on
account of its sulphur content, which causes darkening when mixed with
lead pigments, and corrosion when applied to iron or steel. The darkness
of the photograph is due to the massing of the pigment particles.

=Chrome Green.= Chrome green is prepared as a paint pigment from nitrate
of lead, Chinese blue, and bichromate of soda. It has a gravity of 4 and
is liable to contain slight traces of lead salts. The particles when
magnified appear very fine and flocculent. This color is often
precipitated on pigments, such as barytes, which do not reduce its tone.

=Bone Black.= By grinding the carbonaceous matter resulting from the
charring of bones, in iron retorts, the pigment bone black is prepared.
It contains about 15% of carbon and 85% of calcium phosphate. It has a
gravity of 2.7. Comparatively large particles of charred bone can be
seen scattered throughout the mass, resulting from the difficulty of
grinding to a uniform size.

=Carbon Black.= This form of very pure carbon results from the
combustion of gas. Its gravity, 1.09, is lower than that of lampblack,
which shows a gravity of 1.8. It is used in much the same way and for
the same purposes as lampblack. In physical appearance it shows great
similarity to the particles of lampblack.

=Lampblack.= This pigment, made from the combustion of oils, consists
very often of more than 99% carbon. It has wonderful tinting value. The
particles show a fine, fibrous structure with a tendency toward
agglomeration. They differ greatly in physical appearance from those of
either graphite or bone black, being exceedingly more uniform than the
latter.

[Illustration: Zinc Chromate]

[Illustration: Prussian Blue]

[Illustration: Ultramarine Blue]

[Illustration: Chrome Green]

[Illustration: Bone Black]

[Illustration: Carbon Black]

=Graphite.= Graphite, both in the natural and artificial form, contains
impurities such as silica, iron oxide and alumina, but the natural form
has a much greater percentage of these foreign materials, in some cases
as high as 40%. Graphite is usually mixed with other pigments, such as
red lead and sublimed blue lead, thus serving better as a paint coating.
The difference in physical appearance of the various carbon pigments is
interesting, as each pigment has characteristics of its own. In graphite
we find a great tendency toward agglomeration or massing of particles.

=Mineral Black.= Mineral black is a pigment made by grinding a black
form of slate. It contains a comparatively low percentage of carbon and
consequently has low tinting value. It finds use as an inert pigment in
compounded paints, especially for machine fillers. The pigment has a
flocculent appearance, the particles showing a strong tendency to mass.

Photomicrographs of two combination paint pigments are here given, to
show the various pigments as they appear under the microscope, when in
combination.

PERCENTAGES OF OIL REQUIRED FOR GRINDING VARIOUS DRY PIGMENTS INTO
AVERAGE PASTE FORM

  White lead (corroded)                           9%
  White lead (sublimed)                          10%
  Zinc lead (American)                           12%
  French process zinc oxide                      17%
  American process zinc oxide                    16%
  Blanc fixe                                     30%
  Barytes (natural)                               9%
  Paris white (whiting)                          20%
  Terra alba (gypsum)                            22%
  Floated silica or Silex                        26%
  Kaolin (China clay)                            28%
  Asbestine                                      32%
  Blue, ultramarine                              27%
  Blue, Chinese or Prussian                      50%
  Black, gas carbon                              82%
  Black, lamp                                    72%
  Black, drop                                    60%
  Black, bone                                    50%
  Brown, mineral                                 24%
  Brown, vandyke                                 50%
  Chrome yellow, lemon                           23%
  Chrome yellow, medium                          30%
  Chrome yellow, orange                          20%
  Chrome yellow, dark orange                     15%
  Chrome green, Chem. pure light                 21%
  Chrome green, Chem. pure extra dark            25%
  Chrome green, 25%, color light                 13%
  Chrome green, 25%, color extra dark            17%
  Graphite (pure)                                40%
  Indian red, (98%)                              20%
  Ochre, yellow, American                        26%
  Ochre, yellow, French                          28%
  Ochre, golden                                  28%
  Red, Venetian                                  23%
  Red, Oxide                                     25%
  Red, Tuscan                                    27%
  Red, Turkey                                    28%
  Red, lead                                      12%
  Red, lake                                      55%
  Sienna, Italian, raw                           52%
  Sienna, Italian, burnt                         45%
  Sienna, American, burnt                        38%
  Sienna, American, raw                          40%
  Ultramarine green                              28%
  Umber, Turkey, raw                             48%
  Umber, Turkey, burnt                           47%
  Umber, American, burnt                         36%
  Umber, American, raw                           38%
  Verona green (terra verte or green earth)      32%
  Vermilion, English (quicksilver)               14%
  Vermilion, American (chrome red)               16%
  Paris green, American                          23%
  Zinc chromate (permanent yellow)               15%

[Illustration: Lampblack]

[Illustration: Graphite]

[Illustration: Mineral Black]

[Illustration: Asbestine and Whiting]

[Illustration: Silica and Asbestine]



CHAPTER IV

PHYSICAL LABORATORY PAINT TESTS


For the paint chemist who desires to familiarize himself with the more
recent analytical methods worked out in American laboratories, reference
may be had to treatises on the analysis of paints, by Gardner and
Schaeffer,[16] and Holley and Ladd.[17] Analytical methods are not
included in this chapter, the writer's desire being to treat the subject
from the standpoint of the physical properties of painting materials.
The work outlined herein is of a nature that affords a wide field of
research, and a brief study will doubtless suggest similar work to the
student of paint.

  [16] The Analysis of Paints and Painting Materials. McGraw-Hill Book
       Co., New York, 1910.

  [17] Mixed Paints, Color Pigments and Varnishes. John Wiley & Sons,
       New York, 1908.

=Preparation of Paint Films.= The study of paint films is one that has
become of vital importance, and is receiving at the present time great
attention. Among the many methods which have been suggested and
attempted for securing paint films, a few already well known may be
mentioned.

By painting upon zinc and eating away the zinc with acid: The objection
to this method is very evident, namely, the action of the acid upon the
paint coating, which is likely to be very severe. Another method has
been to spread paraffin on a glass plate, and painting upon this
surface. When the paint is dried, the paraffin is melted off and thus
the film is obtained. This method is open to objections, in that the
paraffin surface is not a comparable one upon which to paint, and also
that the complete removal of the paraffin is not assured.

Another method consists in covering a piece of glass with tin foil,
painting out the film upon the foil, and after drying properly, to
remove the sheet of foil with its coating of paint and immerse in a bath
of mercury which, by amalgamation of the tin, leaves the paint film.

We now come to a method worked out in our laboratories, which can be
recommended as being not only simple but efficient and practical. It has
been found that a size from noodle glue, when painted upon ordinary
fair-quality paper, makes a surface from which the paint may be
subsequently stripped. The paint is applied in the ordinary way to the
paper, which is held during the operation by thumb tacks, and allowed to
dry. The paint may be separated by immersion in water kept at about 50
degrees Centigrade. By this method large films may be obtained, but it
has been found very unhandy to work with films exceeding an area of
eight inches square. When the film of paint has been detached from the
sized paper through the dissolving of the noodle glue, the paint film is
then immersed in a fresh solution of water, in order to remove whatever
excess of noodle glue there may be remaining. A glass rod is then
introduced into the bath, in which the paint film is floated upon the
glass rod, which is then hung up to dry in a suitable container to
prevent the accumulation of dust, etc.

[Illustration: Bottles Showing Relative Permeability of Films by Amount
of Whiting Formed Within]

=The Permeability of Paint Films.= A series of tests were made to
determine the water-excluding values of various combinations of painting
pigments ground in pure linseed oil. White pine boards, six inches long,
four inches wide, and one inch thick, were carefully prepared and
numbered and given three coats of a white paint formula of the
corresponding number. After drying, the boards were carefully weighed
and immersed in a tub of water for three weeks. After removal, the
surfaces of the boards were dried with blotting paper and the boards
weighed. The gain in weight, corresponding to the amount of water
penetrating through the pores of the wood, was observed. The boards were
again immersed and at the end of two months the following results were
obtained:

                                  Grammes of water
  Formula                            absorbed
    No.                            through paint

   1. Soya bean oil                    120
   2. Linseed oil                      102
   3. Calcium sulphate                  93
   4. Barytes                           88
   5. Asbestine                         74
   6. Corroded white lead               59
      { Basic carb.--White lead  25% }
      { Basic sulph.--White lead 20% }
   7. { Zinc oxide               25% }  58
      { Calcium sulphate         25% }
      { Calcium carbonate         5% }
   8. Sublimed white lead               56
   9. Zinc oxide                        56
       { Zinc lead white         30%  }
  10.  { Zinc oxide              40%  } 42
       { Basic carb.--White lead 20%  }
       { Calcium carbonate       10%  }
  11. { Basic carb.--White lead  50% }  42
      { Zinc oxide               50% }
       { Basic carb.--White lead 38%  }
  12.  { Zinc oxide              48%  } 38
       { Silica                  14%  }

The test boards were then exposed, with their content of water, to the
action of the sun's rays. Blistering of the painted surfaces took place
in many cases, caused by the rapid withdrawal of the water and its
consequent action on the paint film. The tests seem to indicate that a
mixture of white lead and zinc oxide, with or without a small percentage
of the inert pigments, is not as subject to the action of the water as
the single pigment paints. In order, however, to corroborate these
tests, it occurred to the writer to develop a more visible means of
demonstrating the passage of moisture through paint films.

[Illustration: Bell Jar Apparatus for Testing Permeability of Paint
Films

Paint films sealed over mouths of Bottles containing Lime Water.
Carbonic Acid Gas generated under Bell Jar passes through Plate Films
and precipitates Calcium Carbonate]

Another series of white pine boards were therefore soaked in a solution
of iron sulphate for several hours. After removal, the surface of each
board was dried and coated with one coat of the paints previously
tested. After thorough drying for forty-eight hours, there was placed on
the surface of each board a few drops of a solution of potassium
ferrocyanide. This solution has the effect of producing a blue
coloration with iron sulphate, and in every case when it was placed on a
paint of considerable porosity, the solution penetrated through and
formed a blue coloration beneath the paint. The results corroborated the
original tests referred to above.

A series of sheets or films of paints were then prepared according to
the method referred to on page 71. These films were placed over glass
dialyzing cups, allowing the inner surfaces to sag so as to hold a small
amount of dilute ammonium chloride solution. Distilled water was placed
on the reverse side of the dialyzing apparatus and the tests started. At
the end of six days the distilled water in each test was examined and
the following results obtained:

     Test No. 1 (corroded white lead and asbestine film) allowed the
     passage of 0.002 gm. ammonium chloride. Test No. 2 (corroded
     white lead and zinc oxide film) allowed the passage of 0.0003 gm.
     ammonium chloride.

Tests were also made with dilute solutions of other salts such as ferric
chloride, having a dilute solution of potassium sulpho-cyanide on the
reverse side of the apparatus. In the latter case the formation of a
pink color, characteristic upon the mingling of these solutions, was
obtained in a few hours.

=Film-Testing Machine.= A film-testing apparatus, termed a "filmometer"
by its originator, Mr. R. S. Perry, was constructed, with the following
features: A graduated upright tube is fixed by means of sealing wax to
two metallic plates which carry an evenly bored hole, exactly under the
hole in the upright tube. This hole measures exactly one square
centimeter in area, and is circular. The upright tube is graduated into
lineal centimeters and is called the pressure tube.

[Illustration: Gardner Accelerated Test Box]

[Illustration: Perry Film Testing Machine]

Attached to the lower end of this pressure tube, close to the metallic
plates which serve as carriers for the paint film to be tested, is a
side-neck, which is inclined at an angle of 45 degrees to the pressure
tube, and serves the purpose of introducing the mercury, as will be
described later. Immediately under the openings in the metallic plates
which carry the film are arranged two pieces of iron inclined at a
90-degree angle, so arranged that when the pressure of mercury is
applied and causes rupture of the film, the falling mercury shall be
caught between these two insulated plates and cause contact. These two
plates are connected up by wire with a pair of magnets, thence to an
electric bell, and from there to storage batteries which supply the
current.

A film of paint is tested in the following manner: A piece of film one
inch square is cut out and placed between the two metallic plates which
hold the film immediately under the pressure tube. Mercury is run in
from a burette through the side-neck and applies pressure upon the film
by gravity. As the mercury is run in it rises of course in the tubes
until this pressure becomes so great as to finally break the film. At
this point the mercury will run out, and, falling upon the two insulated
iron plates immediately below, will cause contact and close the circuit
which rings an electric bell, which is a signal for the operator to shut
off the inflow of mercury through the side-neck from the burette.

The pressure tube is also supplied with a piston which is made of a
piece of thin iron wire having a disc attached to its lower end. As the
mercury rises in the pressure tube this iron wire is pushed up, being
very delicately counterpoised over a wheel. Upon the breaking of the
film the mercury runs out, but upon falling upon the two iron plates
underneath causes contact to be made, which causes the current to run
through the pair of magnets before mentioned, which, becoming
electrified, attract the piston in the pressure tube, giving a reading
for the maximum height of the column of mercury.

[Illustration: Diagram of Perry Filmometer]

The supply of mercury being shut off, the operator is now in a position
to determine the total sum of both the elasticity and ductility of the
paint film, and also the pressure at which the film broke. The breaking
pressure of course is read directly upon the pressure column, which is
divided into centimeters as has been described above, the piston
indicating the maximum height of the mercury column. What may be termed
the elasticity of the film can now be calculated. As is perfectly
evident, the film in stretching does so by distending from a flat
surface to a curved or cup-like surface. If the pressure tube is
calibrated in cubic centimeters reckoned from a flat surface where the
film was introduced, the stretch of the paint film in distending from a
flat surface to a curved surface may be determined. The cubic contents
of the pressure tube and side-arm become increased, owing to the
cup-like shape the paint film takes on. By subtracting the amount of
mercury indicated by the piston in the pressure tube from the amount of
mercury delivered from the burette, the amount contained in the
distended paint film is obtained, which serves as a measure of
elasticity. The temperature is a most important point to consider in
running daily tests upon the filmometer. The tests made by the writer
were conducted at 70 degrees Fahrenheit throughout.

[Illustration: Gardner-de Horvath film testing apparatus]

=Gardner-de Horvath Filmometer.= Another type of filmometer which gives
very concordant results was recently devised by the writer and de
Horvath. This apparatus is shown above.

It consists of a three-necked Wolff bottle having provision at one of
its necks for exhausting the air from the bottle. The reverse neck is
provided with a gauged glass tube dipping into a porcelain crucible
containing mercury, thus acting as a manometer. The middle neck is
fitted to accommodate two ground glass plates. Both these plates are
provided with a central orifice one millimeter in diameter. Between the
plates is placed a small section of paint film. The plates may be
pressed together or clamped together and placed over the middle neck of
the bottle, a close contact being made with Canada balsam. As the air is
exhausted from the bottle, the mercury in the tube will rise and
continue in its ascent until the film, which is exposed to atmospheric
pressure, has offered it maximum resistance, which is shown by the
breaking point. This point is observed on the manometer and the result
expressed in centimeters of mercury.

=Table of Film Testing Results.= By means of the Perry film-testing
apparatus, described in the above, interesting results have been
obtained, which are embodied in the following table:

COMPARATIVE STRENGTHS OF FILMS AS OBTAINED BY THE BREAKING MACHINE

  ============================+=========+==========+===========+========
                              |No. Coats| Pressure | Thickness | Stretch
  ----------------------------+---------+----------+-----------+--------
   1. Zinc oxide              |    3    |   33.2   |    0028   |  .30
   2. Zinc lead               |    3    |   32.7   |    0034   |  .35
   3. Asbestine               |    3    |   28.0   |    0045   |  .15
   4. Sublimed white lead     |    3    |   17.9   |    0024   |  .38
   5. Barytes                 |    3    |   13.3   |    0042   |  .33
   6. Lithopone               |    3    |   13.1   |    0024   |  .49
   7. Whiting                 |    3    |   13.0   |    0033   |  .32
   8. Quick process white lead|    3    |   11.3   |    0025   |  .38
   9. Gypsum                  |    3    |   10.8   |    0039   |  .29
  10. China clay              |    3    |   10.8   |    0035   |  .16
  11. Silex                   |    3    |    9.6   |    0032   |  .32
  12. Blanc fixe              |    3    |    8.5   |    0030   |  .28
  13. Corroded white lead     |    3    |    7.3   |    0020   |  .33
  14. Barium carbonate        |    3    |    7.2   |    0028   |  .16
  ============================+=========+==========+===========+========

By means of this machine it is possible to obtain very valuable
information concerning the effect of age upon a paint as influencing its
strength and elasticity. These are two vital qualities in a paint, as it
is through its strength that a paint resists abrasion, cracking,
peeling, and blistering. That elasticity is a vital qualification of a
paint may easily be seen through the checking of oil paintings, which,
as Ostwalt has pointed out, is due to the unequal coefficients of
expansion between the ground and the paint. This is particularly
noticeable in the alligatoring of many enamels which contain large
percentages of zinc.

Curves have been prepared having pressure as an abscissa and elasticity
as ordinate. These curves show remarkable differences in different
pigments. For instance, in the case of white lead, the curve takes a
steep upward trend when it apparently reaches a maximum, the curve then
flattening out and finally taking another steep upward trend just before
breaking. This may be construed as follows: That under low pressures the
white lead film is perfectly elastic, when a maximum is obtained, beyond
which elasticity does not extend. This point is the maximum point of the
upward trend. From here on pressure may be applied without any increase
in stretch, this being represented by the flat part of the curve, while
the steep upward trend just before breaking shows where the paint begins
to tear, finally culminating in breaking. In the case of asbestine,
however, the curve is more of a straight line up to the breaking point,
which would go to prove that elasticity is proportionate to pressure in
the case of this pigment.

=Moisture Absorption.= The structure of certain pigments is such that
when they are ground in linseed oil and painted out, films are produced
which are very water-resistant. This action is possibly due to the
filling of the voids in the oil, thus making a compact and
water-resistant film. Pigments which are coarse and which present an
angular crystalline structure, often produce films which contain a
relatively large number of voids and are less waterproof. Certain
pigments are chemically active and tend to produce, when ground in oil,
metallic soaps which act for a time more or less as varnish gums, in
keeping out moisture. Later on, however, such films are apt to break
down and admit moisture in quantity. The tests herein described were
designed by the author to determine the water-excluding value of a
number of typical pigments when ground in linseed oil and painted out
into films. Unfortunately, no method has been devised by which films of
the same gauge could be prepared. The variations in the thickness of the
films used in these experiments, however, are not very great.

[Illustration: Apparatus for Determining Excluding Properties of Paint
Films]

A series of small glass bottles with wide mouths, holding about two
ounces, were half filled with concentrated sulphuric acid, and paint
films were tightly sealed over the mouths of the bottles with Canada
balsam. The bottles were then carefully labeled, numbered, and
accurately weighed upon chemical balances. Later they were exposed under
a large glass bell jar containing air saturated with moisture and kept
at a constant temperature. The bottles were removed from the receptacle
every week and reweighed. The increase in weight, due to the amount of
moisture which had penetrated through the films, and absorbed by the
sulphuric acid, owing to its hygroscopic nature, was thus determined. In
another series of bottles, lumps of calcium chloride were substituted
for the sulphuric acid. The results obtained from these tests correspond
to those of the former tests, and led to the conclusion that the
porosity of linseed oil films varied when different pigments were used
in the oil.

MOISTURE EXPERIMENTS

Figures Given Express Percentage Gain in Weight, e.g., Water Absorbed

  ==========================+=========+=========+=========
                            |  7 days | 21 days | 49 days
  --------------------------+---------+---------+---------
  White lead and zinc oxide |  0.043% |  0.115% |  0.266%
  Zinc lead white           |  0.049  |  0.130  |  0.284
  Red lead                  |  0.049  |  0.130  |  0.295
  Sublimed white lead       |  0.049  |  0.128  |  0.292
  Zinc chromate             |  0.064  |  0.176  |  0.417
  Zinc oxide                |  0.065  |  0.172  |  0.391
  Barytes                   |  0.074  |  0.202  |  0.466
  Willow charcoal           |  0.077  |  0.236  |  0.694
  Lithopone                 |  0.083  |  0.228  |  0.550
  Chinese blue              |  0.092  |  0.276  |  0.671
  Natural graphite          |  0.104  |  0.350  |  0.951
  Ultramarine               |  0.119  |  0.336  |  0.814
  ==========================+=========+=========+=========

Another series of tests was started, in which were used films prepared
from various oils and varnishes made especially for the test from
different gums. The results of this series are very interesting, as they
indicate that certain gums are more powerful than others in making oils
resistant to moisture. The reader should study with care the data on
treated Chinese wood oil, most excellent results having been obtained
when it was used in the proper percentage.

EXCLUDING TESTS ON OIL VEHICLES AND VARNISHES SHOWING PERCENTAGE OF
MOISTURE ABSORBED AT VARIOUS PERIODS

  ===================================+=========+=========+=========
                                     |  6 days | 18 days | 24 days
  -----------------------------------+---------+---------+---------
  Linseed oil, 100%                  |  .233   |  .686   |  .895
  Soya bean oil, 100%                |  .340   | 1.06    | 1.39
  Linseed oil, 80%  }                |  .250   |  .755   |  .987
  Soya bean oil, 20%}                |         |         |
  Linseed oil, 60%   }               |  .289   |  .857   | 1.125
  Soya bean oil, 40% }               |         |         |
  Linseed oil, 40%  }                |  .355   | 1.05    | 1.39
  Soya bean oil, 60%}                |         |         |
  Linseed oil, 20%   }               |  .260   |  .789   | 1.03
  Soya bean oil, 80% }               |         |         |
  China wood oil treated, 100%       |  .130   |  .297   |  .375
  Linseed oil, 80%           }       |  .182   |  .559   |  .728
  China wood oil treated, 20%}       |         |         |
  Linseed oil, 60%            }      |  .173   |  .540   |  .708
  China wood oil treated, 40% }      |         |         |
  Linseed oil, 40%           }       |  .119   |  .348   |  .450
  China wood oil treated, 60%}       |         |         |
  Linseed oil, 20%            }      |  .127   |  .375   |  .494
  China wood oil treated, 80% }      |         |         |
  Kauri gum, 33%  }                  |         |         |
  Linseed oil, 33%}                  |  .061   |  .191   |  .302
  Turpentine, 33% }                  |         |         |
  Kauri gum, 25%   }                 |         |         |
  Linseed oil, 50% }                 |  .096   |  .266   |  .346
  Turpentine, 25%  }                 |         |         |
  Kauri gum, 20%  }                  |         |         |
  Linseed oil, 60%}                  |  .122   |  .367   |  .449
  Turpentine, 20% }                  |         |         |
  Kauri gum, 15%   }                 |         |         |
  Linseed oil, 70% }                 |  .187   |  .421   |  .601
  Turpentine, 15%  }                 |         |         |
  Congo copal gum, 20% }             |         |         |
  Linseed oil, 50%     }             |  .228   |   --    |   --
  Turpentine, 30%      }             |         |         |
  Sierra Leone copal, 20% }          |         |         |
  Linseed oil, 50%        }          |  .099   |   --    |   --
  Turpentine, 30%         }          |         |         |
  Zanzibar gum, 20% }                |         |         |
  Linseed oil, 50%  }                |  .082   |   --    |   --
  Turpentine, 30%   }                |         |         |
  Amimi gum, 20%   }                 |         |         |
  Linseed oil, 50% }                 |  .080   |   --    |   --
  Turpentine, 30%  }                 |         |         |
  Boiled linseed oil (linoleate type)|  .210   |   --    |   --
  Collodion solution (6 oz.), 80% }  |  .201   |   --    |   --
  Boiled linseed oil, 20%         }  |         |         |
  ===================================+=========+=========+=========

[Illustration: Microscopic view of section of cedar]

[Illustration: Microscopic view of section of maple]

[Illustration: Microscopic view of section of white pine]

[Illustration: Gardner photomicroscope in position against painted
surface]

[Illustration: Inside White on White Pine]

=Use of the Microscope.= 4. The microscope is a necessary adjunct of
every well-ordered paint laboratory, as has been recognized throughout
the whole paint industry. The writer has attempted to collect certain
data which may materially assist those manufacturers who employ this
instrument to judge of the quality of their raw and finished products.
The fineness of grinding considerably affects the quality of the paint,
and this can be easily controlled through the intelligent use of the
microscope. This instrument may also be used to detect certain
adulterations. Appended is a table giving the fineness of grinding of
the various pigments, together with their characteristics under the
microscope. In this table measurements are given both in millimeters and
in inches, in order to accommodate itself to the use of those chemists
employing a millimeter stage micrometer, or those employing the English
or inch system. Although it is not yet certain that any and all
combinations of pigments may be detected under the microscope the writer
is working toward a method which will allow a manipulator to judge of
the composition of the paint under observation.

In order to properly prepare a paint for microscopic examination, the
following method is recommended: A microscopic turn-table is a
convenient accessory of the microscope, and its use is to be
recommended. A glass slide being placed in position upon the turn-table,
a very small amount of either the pigment rubbed up in oil, or the
paint, is applied to the slide; a small drop of Canada balsam is then
applied by means of a glass rod dipped in a solution of balsam in xylol,
and dropped upon the slide. The rod is then used to thoroughly
incorporate the pigment with the balsam, and a cleaned cover glass is
dropped over the whole and pressed down tightly, so that a small amount
of balsam will exude from under the edges and thus firmly seal the
glass. In order to make permanent slides it has been found advisable to
rim the cover glass with balsam and even follow this up with some
suitable black varnish, the slide being then carefully labeled and
placed in the collection. Following is a table of the characteristics of
the fourteen chief pigments:

TABLE OF THE SIZE OF PARTICLES OF THE CHIEF PIGMENTS WITH THEIR
CHARACTERISTICS UNDER THE MICROSCOPE

  ===+===================+======================+=======================
     |                   |      Diameter in     |      Diameter in
     |                   |      Millimeters     |        Inches
     |                   +-------+-------+------+-------+------+--------
  No.|Name               | Small | Aver. |Large | Small | Aver.| Large
  ---+-------------------+-------+-------+------+-------+------+--------
    1|Asbestine          |.002   | --    |.12   |.00015 | --   |.049
    2|China clay         |.003   | --    |.065  |.00009 | --   |.025
    3|Barium carbonate   |.00076 |.0055  |.0172 |.00003 |.00024|.0011
    4|Blanc fixe         |.00073 |.0037  |.0073 |.00003 |.00014|.0003
    5|Silex              |.0037  |.0092  |.03   |.00014 |.00036|.0012
    6|Gypsum             |.0037  |.011   |.05   |.00014 |.00044|.0022
    7|Amer.-Paris white  |.0015  |.0050  |.04   |.00006 |.00022|.0018
    8|Barytes            |.0015  |.0092  |.05   |.00006 |.00036|.0021
    9|Zinc lead          |.00037 |.0018  |.0037 |.000014|.00007|.00014
   10|Sublimed white lead|.00037 |.0018  |.0037 |.000014|.00007|.00014
   11|Lithopone          |.00076 |.0018  | --   |.00003 |.00007| --
   12|Zinc oxide         |.00046 |.0018  |.00037|.00002 |.00007|.00014
   13|Quick Pro. lead    |.00061 |.0030  |.0048 |.00002 |.00012|.00018
   14|Dutch Pro. lead    |.00061 |.0018  |.0066 |.00002 |.00007|.00026
  ===+===================+=======+=======+======+=======+======+========

=Film Sectioning and Deductions to be Drawn Therefrom.= 5.
Investigations were undertaken into the innermost structure of paint
films as revealed under the microscope. Up to the present time, work has
been done upon barytes, asbestine, blanc fixe, and white lead, painted
upon wood, and a combination paint upon wood. The films, the preparation
of which has been described in the foregoing, were sectioned and
prepared for microscopic examination in the following manner:

A solidifying dish was partly filled with low melting-point paraffin
which was allowed to harden, when a small piece of paint was thrown upon
it and then more paraffin poured over it. After hardening, sections were
obtained of the paint film by means of a microtome.

[Illustration: Section Barytes Film]

A view of these sections of paint films under the microscope gave to the
operator a better idea of the structure of a paint than had ever been
afforded heretofore. It was easy to perceive the relative position of
the pigment particles and the three coats. The penetration of one coat
into another was easily discernible, and measurements were made upon the
sections in order to determine the average thickness of coat and its
general appearance.

Sections were also made of Inside and Outside White upon wood. These
sections revealed under the microscope the thickness of the coats and
also the penetration of the priming coat into the wood. Appended is a
table giving microscopic measurements.

PAINT SECTION MEASUREMENTS UNDER MICROSCOPE

  ======================+=============+===========+======
                        |             |Millimeters|Inches
  ----------------------+-------------+-----------+------
  Barytes               |3 coats (sum)|  .1068    |.00421
                        |Single coat  |  .0356    |.00140
                        |             |           |
  Inside. White on wood |3 coats (sum)|  .1624    |.00639
                        |Outside coat |  .0230    |.00091
                        |Next coat    |  .0443    |.00175
  Field in photographs  |Next coat    |  .0620    |.00245
                        |Penetration  |  .0294    |.00116
  White lead            |Inside       |  .0215    |.00085
                        |Middle       |  .0405    |.00159
                        |Outside      |  .0184    |.00073
                        |3 coats (sum)|  .0811    |.00319
  Asbestine             |3 coats (sum)|  .1840    |.00725
                        |             |           |
  Blanc fixe            |3 coats (sum)|  .1068    |.0042
                        |Single coat  |  .0356    |.00014
                        |             |           |
  Outside. White on wood|Outside coat |  .1329    |.00523
                        |Inside       |  .1845    |.00727
                        |Penetration  |  .0737    |.00290
  ======================+=============+===========+======

=Polar Micro-Examinations and Photomicrographs.= By Polar
Micro-Examination is meant the examination of pigments under polarized
light. A polarizing apparatus, though not an essential in the hands of
the paint chemist, is nevertheless much to be desired, for by its help
deductions may be drawn as to the contents of a paint, which by other
means might not be possible. The polarizing apparatus as marketed by
most manufacturers of the microscope is attached in the following
manner:

The diaphragm immediately under the sub-stage container is swung out and
opened to its widest limit, allowing the insertion of the polarizer.
This polarizer carries one of the pair of Nicols prisms and is
countersunk to allow of the introduction of gypsum or selenite plates.
The analyzer fits over the eyepiece on the tube.

The use of polarized light upon paint is valuable on account of its
action upon crystalline substances. The re-enforcing pigments, such as
Asbestine, China Clay, Gypsum, Silex, Barytes, etc., are crystalline and
consequently act upon the polarized light. In most cases these pigments
are used in ready-mixed paints in small amounts, varying between 5 and
25%. When a slide containing a small amount--for example, less than
3%--of these crystalline pigments is examined under the microscope by
ordinary transmitted light, they will often escape observation, owing to
the small amount in which they are present. However, in the case of
polarized light, this could hardly happen.

[Illustration: Microscopic View of Barytes under Polarized Light]

A slide of paint containing these re-enforcing pigments is prepared in
the usual manner. On examining this under the microscope and using the
polarizing apparatus, the crystalline pigments are at once detected by
revolving the analyzer. At one position of the analyzer, one sees an
ordinary field, as with transmitted light, but if one revolves the
analyzer, the field gradually becomes darker until total darkness is
obtained throughout, except in such places where crystalline substances
are present, when the crystal is shown up with beautiful distinctness.
Photomicrographs of various single pigments and pigment combinations are
shown under Chapter III.

=Effect of Pigments on Oil.= Certain pigments have the property of
acting upon the linseed oil in which they are ground, forming metallic
linoleates which accelerate the drying of oil. This is especially true
of lead and zinc pigments. The inert crystalline pigments, when ground
in linseed oil and painted out, distribute the oil so as to allow a
great surface to be exposed to the air. Thus by physical action, and
possibly catalytic or contact action, these inert pigments stimulate the
drying of oil paints in which they are ground. Lead and zinc paints, of
course, have the greatest drying values on account of the added effect
of the linoleates formed, as outlined above. The writer has made a
series of tests in which the action of various pigments upon linseed oil
is shown. The tests were made in the following manner:

Five grams of each of a series of commonly used paint pigments,
including those of inert crystalline nature as well as the more valuable
amorphous pigments which are considered more or less chemically active,
were ground separately in an agate mortar, with 5 grams of raw linseed
oil. The ground paste in each case was placed in a marked glass beaker,
and allowed to stand in a dustless section of the laboratory for one
month. The oil-pigment paste from each beaker was then separately
extracted with benzine to remove the linseed oil from the pigment. The
benzine solutions of oil were then heated to remove the benzine and the
residue of oil burned to ash in crucibles. The ash from each test was
weighed, and if it ran above the percentage of ash determined on a blank
sample of linseed oil (namely, .003%), the ash was analyzed
qualitatively for metallic constituents. The following table of results
shows the percentage increase in ash, as well as the constituents of ash
on the various samples tested:

TABLE OF RESULTS

  ===============================+==============+========================
                                 | Per cent. of |
                                 |  Ash in Oil  |
  Pigment in Oil                 |Extracted from|Analysis of Ash
                                 | Oil-Pigment  |
                                 |    Paste     |
  -------------------------------+--------------+------------------------
  Raw linseed oil without pigment|    0.003     |      --
  Barytes                        |    0.003     |      --
  Blanc fixe                     |    0.003     |      --
  Silica                         |    0.003     |      --
  Asbestine                      |    0.005     |      --
  China clay                     |    0.007     |      --
  Whiting                        |    0.008     |      --
  Chrome yellow                  |    0.025     |Lead oxide (PbO)
  Lithopone                      |    0.031     |Zinc oxide (ZnO)
  Prussian blue                  |    0.032     |Iron oxide (Fe_{2}O_{3})
  Sublimed white lead            |    0.033     |Lead oxide (PbO)
  Zinc oxide                     |    0.105     |Zinc oxide (ZnO)
  Corroded white lead            |    0.116     |Lead oxide (PbO)
  Red lead                       |    0.2112    |Lead oxide (PbO)
  ===============================+==============+========================

Observation of these results shows that pigments such as Barytes, Blanc
Fixe, and Silica have no chemical action on the linseed oil. The results
on Asbestine and China Clay also are negative, the extremely slight
increase in amount of ash from these samples probably being due to
traces carried over mechanically into the oil mixture; the last named
pigments being more fluffy and difficult to separate from oil. Slight
action seemed to be apparent in the case of whiting, a pigment somewhat
alkaline in nature. A longer test might have shown this pigment to have
possessed still greater action. Corroded white lead showed considerable
action, resulting in the formation of lead linoleate or some other
organic compound. Zinc oxide and lithopone, the latter pigment
containing 30% of zinc sulphide, both indicated action on the oil.
Chrome yellow (chromate of lead) showed some action, as did also
Prussian blue, the ash from the last named pigment showing a heavy
percentage of iron oxide.

Red Lead showed a most astounding gain in these tests, chemical action
of the pigment on the oil being apparent soon after the tests were
started, as shown by the formation of a hard cake with the linseed oil.

The Raw Linseed Oil which was used in these tests had an acid value of
1.84%, which is very low. The neutralization of this free fatty acid by
some of the alkaline pigments used, may account for part of the
increased percentage of ash, but in most cases the pigments, and more
especially the basic pigments, had a direct saponifying action upon the
glycerides of the oil.



CHAPTER V

THE THEORY AND PRACTICE OF SCIENTIFIC PAINT MAKING


=Laws of Paint Making.= To secure a proper comprehension of the
composition of paints, and to be able to interpret the functions of
their various constituents, requires an understanding of the general
physical principles involved. The modern grinder has accepted the Law of
Minimum Voids, and upon this law he bases the design of paint formulæ,
aiming toward the production of what have been properly termed
Scientifically Prepared Paints. Perry's formulation of the Law of
Minimum Voids in a paint coating, and the analogy which he has drawn
between a scientifically prepared paint and a well-proportioned
concrete, was the result of genuine scientific thought following
observation and experimentation. It must be admitted that analogies are
not always safe to draw conclusions from, but it surely is no fallacy in
reasoning to draw analogies between these two materials, when they
resemble each other in so many ways. To carry out processes of
reasoning, and to formulate laws from such close analogies, is certainly
a step in the right direction.

A graphic summary of the analogies between a properly proportioned
concrete and a paint, are shown on next page.

Although this table graphically summarizes the principles involved, the
matter is presented with greater clearness in the following:

Law No. 1--The law of minimum voids to be observed in constructing a
paint formula--this law having already been accepted as mathematically
correct and technically proved in the technology of concrete and cement.

Corollary--The requisite thickness of a paint film together with the
utmost attainable strength and impermeability can best be obtained by a
properly proportioned blend of pigments of three or more determinate
sizes.


AN EXHIBITION OF CERTAIN ANALOGIES GOVERNING THE MANUFACTURE OF CONCRETE
AND OF PAINT

  1 Concrete aggregate = solids + vehicle|Paint aggregate = solids + vehicle
                                         |
  2 Solids = coarse + medium + fine      |Solids = coarse +     medium  + fine
             (stone) (gravel) (sand)     |        {pulverized }{precipi-}
                                         |(pig-   {cryst'lline}{tated   }(fume)
                                         |(ments  {(etc.)     }
                                         |
  3 Vehicle =                            |Vehicle =
    = reactive binder + evapor'g thinner |= reactive binder+evaporating thinner
     { cement and com- } (excess water)  |     (linseed oil)    (volatiles)
     { bining water    }                 |
                                         |
  4 Solids + compacting =                |Solids + compacting =
             (tamping)                   |         (brushing)
    = elimination of accidental voids +  | = elimination of accidental voids +
    + proper adhesive contact            | + proper adhesive contact
                                         |
  5 Vehicle + reaction = hydrosilicates, |Vehicle + reaction = linoxyn
    etc.                                 |
              (setting)                  |          (drying)
                                         |
  6 Solids + vehicle +                   |Solids + vehicle +
    + lubrication + chemical reaction =  | + lubrication + chemical reaction =
    = final product { solidified binder+}| = final product {solidified binder+}
                    { + solids          }|                 {+ solids          }
                                         |
  7 Final product = concrete             |Final product = paint coating
                       { shearing       }|              { strength       }
    (of max. strength  { tensile        }| (of maximum  { impermeability }
                       { crushing, etc. }|              { durability     }

                         *       *       *       *       *

  If we assume for both paint and concrete
        proper lubrication
        proper proportion of vehicle and solids
  Then the _essential difference_ between a thin film of

                        Concrete        and             Paint
                                        is

                      Cement Binder                     Linoxyn Binder

                                  _Disadvantages_

  Non-elastic and hence an impracticable |Slowly perishable from oxidation by
  binder for a film to protect non-      |the air.
  similar structural surfaces.           |

                                    _Advantages_

  Durable and with the qualities of a    |Semi-elastic and therefore a practic-
  natural mineral.                       |able binder for a film to protect
                                         |structural surfaces.

  Postulate (def. Webster's Dictionary--A self-evident problem)

     Postulate No. 1--The organic linoxyn or semi-elastic binder of the
     paint vehicle (unlike the cement binder) is perishable and its purity,
     strength and protection from attack means life to the paint coating,
     and hence the _life_ of the oil is the _life_ of the paint.

     Postulate No. 2--The inorganic or powdered mineral solids of a paint
     coating will crumble unless held together by the binder, but the
     imperishable pigments must be so ground and blended in the binder that
     they will protect the binder and present the greatest possible solid
     front to the atmospheric attack.

                         *       *       *       *       *

  A paint, to secure the greatest protection and life for the linoxyn,
  together with the durable qualities of cement,

                                    _Therefore_

                            Should expose to air decay

  within limits of physical strength     |within limits required for elasticity,
  The greatest amount of pigm't material |etc. The least amount of exposed
                                         |linoxyn
              (which is)                 |                or
  Durable and with the inert qualities of|Considering the linoxyn present be-
  natural mineral                        |tween pigment particles as the void
                                         |or point of attack,
                                         |               Then
                                         |the minimum exposure of linoxyn
  or minimum voids obtainable by proportioned pigments of different particle
  sizes.

Law No. 2--The law of the flat arch in paint coatings--i.e., the fact
that in studying the fundamental physical principles governing the
strength and durability of a paint coating it is necessary to regard the
coating as consisting of a series of flat arches, in which the pigment
particles of largest characteristic size serve as the piers or supports
for the flat arches of which the continuous film is composed.

Corollary A--The strength and durability of a paint coating is
determined by the strength and durability of the piers or supports
(which consist of the characteristic pigment particles of the largest
size).

Corollary B--Owing to their inherent strength and durability the pigment
particles of largest characteristic size which serve as supports for the
paint coating should consist, in part at least, of chemically inert
pigments, such as natural crystalline barium sulphate, calcium
carbonate, magnesium silicate, etc.

Corollary C--It follows directly that the thickness of a paint coating
is determined by the particles of pigments having the largest
characteristic size, even if that pigment be present only in moderate
percentage. Upon this principle depends the comparatively great
thickness of film and moderate spreading rate of paints composed of such
pigments as basic carbonate--white lead, red lead, barytes, etc., and
the strongly contrasted thinness of film and high spreading rate of
paints composed of the sublimated pigments such as lamp black, zinc
oxide, basic sulphate--white lead, zinc-lead white, leaded zinc, etc.

In commenting upon the announced laws set forth above, Heckel says: "The
recognition of these laws was an exercise of pure deduction. Paint
manufacturers before Mr. Perry's announcement were producing paints
containing three or more pigments with particles of varying
characteristic sizes; but their procedure was based largely on empirical
knowledge, the result of accumulated experience, due to a conscientious
endeavor to produce the highest type of paints for economic service. In
the absence of any law to govern or to limit the use of the reinforcing
pigments, inexperienced manufacturers had brought upon the market paints
which were badly proportioned as to the several pigments, or burdened
beyond the limits of effectiveness with reinforcing pigments. To all
paint manufacturers Perry rendered a substantial service in deducing for
them the laws set forth in his address. In the results following a
recognition of these laws there was nothing new or startling, but Perry
was the first to give the principles from which it can be determined in
advance whether a paint formula will prove to be physically good or bad
in practice.

[Illustration: Series of Paint Chasers, Mixers, and Grinders]

[Illustration: Overhead Churn Mixer]

[Illustration: Battery of Paint Mixers and Grinders of Modern
Underdriven Type]

[Illustration: _Photographs courtesy of Ernest Heath_

View showing Shrinkage in Bulk of Paint Pigment after being ground in
Oil. Filled Barrel on Right with the Oil forms one-third Barrel Paste as
shown in Barrel on Left]

[Illustration: View showing careful Dressing of Bull Stone Mill from
Grinder]

"As has been before stated, he was not the first to recognize the law
governing minimum voids, but by that scientific use of the imagination
which Tyndall so highly commends, he recognized, as by inspiration, the
fundamental similarity existing between a film composed of solid
particles cemented together by a semi-solid homogeneous menstruum and a
layer of concrete composed of solid particles cemented together by a
solid homogeneous medium. His application of the law permits the paint
manufacturers to design a paint formula with full knowledge of the
controlling conditions, so that it shall produce a coating neither too
thick, and therefore uneconomical and subject to excessive internal
strains, nor too thin, and thus weak and inefficient for protection.
That Mr. Perry's contention was well-founded, other paint technologists
have since demonstrated; notably Mr. Wirt Tassin, in his microscopic
studies of paint films in situ, and Prof. G. W. Thompson who, in his
address to the Penna. Association of Master Painters at Reading,
said:--"I want to agree with Mr. Perry * * * where he says that a
pigment should be made up of particles of different sizes. Mr. Perry
also draws a further parallel between paint and concrete where he refers
to the form of the reinforcing pigment particles and suggests that in
paint coatings as in concrete a field can be found for the chemically
inert pigments with rod-like or hair-like structure, to strengthen the
film, just as the steel rods and iron mesh are used to reinforce
concrete in structural work--a suggestion which, since the first
publication of the address, has been widely accepted as a practical aid
in the manufacture of good paints.""

=Use of Inert Pigments.= There seems to be no reasonable doubt as to the
efficiency of a small amount of inert pigments in paint, and the writer
has often compared the manufacture of paint of the above type to the
making of various alloys wherein zinc, copper, and other metals are
added to gold in order to make a product possessed of greater
durability, etc.

[Illustration: Batteries of Color Grinding Mills]

There has been considerable inquiry as to just what is meant by the
statement that "a moderate percentage of inert pigments, combined with
properly adjusted mixtures of white lead and zinc oxide, have given
wonderful service in all the tests." The writer has been asked to define
what "moderate" means. A "moderate percentage of inert pigments" should
be defined as that amount of natural crystalline pigments that will,
when mixed with white lead and zinc oxide, not materially detract from
the hiding power of white lead and zinc oxide. It is possible to mix a
certain percentage of these crystalline pigments with white lead and
zinc oxide, and, by thorough grinding, incorporate them in such a manner
that the mixture will show nearly as good a hiding power as the straight
white lead and zinc oxide. When certain limits have been reached,
however, and these limits must be determined by the manufacturer and
painter in making practical tests, the further addition of inert
pigments lowers the hiding power of the paint and therefore lowers the
value of the paint. These remarks do not apply to artificial crystalline
pigments, such as precipitated whiting, which possess greater hiding
values than the natural pigments.

=Perry's Principles of Paint Making.= Parts of the original paper[18] in
which Perry so clearly set forth the principles from which the preceding
laws were formed, follow:

  [18] Physical Characteristics of a Paint Coating. R. S. Perry.
       Michigan Chapter, Amer. Institute of Architects, 1907.

=Sealing Quality or Imperviousness of the Coating.= "It has been
emphasized that for durability and protection, the strength and
imperviousness of a paint coating are vital factors. The protective
value of the paint coating of course ceases with its chalking or
disintegration, but, while it is true that the protecting or final life
of the coating ceases with this disintegration, it is also true that a
paint coating has always during its true life more or less porosity from
the nature of the linoxin or oxidized linseed oil. Therefore during its
protecting life the degree of its imperviousness influences its
resistance to attack upon its own life and its protection of the
underlying materials. The more impervious the paint coating without loss
of strength, the slower the oxidation or disintegration of the paint
coating itself and the greater protection to the underlying material.

"A coating of linseed oil alone is not only weak, but the simplest and
crudest experiments will show its porosity and this porosity increases
rapidly with progressive oxidation, the porosity of course definitely
hastening the over-oxidation or chalking. In proportion, therefore, to
our success in filling the voids in the linseed oil film with proper
pigment materials, we will in that degree succeed in excluding agencies
of decay, not only from the mass of the paint coating itself, but also
from the surface to be protected. These conditions are exactly parallel
in the requirements and performance of the best-made concrete, and
Taylor & Thompson in their work on concrete have clearly stated that to
obtain imperviousness there must be freedom from voids, and that to
obtain these conditions, the materials used must have at least three
determining sizes.

[Illustration: Equal Volume (One Cubic Centimetre) of Each Size of Shot
Taken. Note that the Smaller Shot Cover more than Half as much again as
the Larger Shot and the Voids are Smaller.]

[Illustration: Diagram Illustrating Two Determining Sizes of Solid
Particles in Concrete]

[Illustration: Diagram Illustrating Three Determining Sizes of Solid
Particles in Concrete]

"'It is a fact that with particles of different sizes as against uniform
size the densest mixture can be obtained. This is so evident as to
require no proof.' It follows that the least density and hence the
largest percentage of voids occur when the grains are all of the same
size, and it is shown that the most voids occur in a mass of large
particles. The least voids occur when the voids between the large
particles are filled with smaller particles and when these smaller voids
between the smaller particles are in turn filled with still finer
particles. In other words--particles with three determining sizes will
fill up a given space more completely than particles of two determining
sizes and very much more completely than particles of one size.

=Elasticity and Strength.= "The paint coating here again is governed by
many of the laws which govern the similar material, i.e., concrete. We
find, by again referring to Taylor & Thompson, on Concrete, page 275,
that tests at the Watertown Arsenal on concrete convinced the
investigators that the ultimate strength of a concrete is identical with
the shearing strength of particles of stone making up the aggregate.

"This means that in its ultimate form the good concrete will crack or
shear through the broken rock contained therein, and resistance to
shearing is directly proportionate to the strength of the broken rock
chosen for the mixture. The film of semi-liquid linseed oil when fresh
is extremely weak, but as it hardens, its characteristics and physical
properties will obviously be those qualities which are a composite of
the qualities of the solid particles and of the semi-solid linolein
incorporated together in the paint coating. These physical properties of
the suspended and incorporated pigments profoundly modify the film in
this respect.

"The dried vehicle, linoxin, is notable for its elasticity, and it is
weak in crushing and tensile strength, and in hardness or resistance to
surface wear. The fact that it is a semi-solid furnishes an opportunity
to modify and improve those characteristics of a solid in which it is
deficient. The semi-solid, rubber-like linoxin between the coarser
particles of the pigment obviously uses these coarser particles as
supporting points. The medium sized particles of the second group of
alteration products serve the same purpose as the broken rock in
concrete. The coarser particles absolutely do not, and can not, serve
the purpose of stiffening or of reinforcing or modifying the consistency
and qualities of the semi-solid linoxin, for a number of reasons, one
of which may be mentioned, namely, that particles of the first, or
coarse, class have a determining size which is a large fraction--a heavy
percentage--of the total thickness of coating, and are in some instances
thicker in diameter than the thickness of an oil coating not reinforced
with the fine or fire group.

"We must think of the coarser particles as piers. The mixture of linoxin
with the other two groups of particles in the spaces between these
coarser particles, or piers, is the true paint body and consists of flat
reinforced arches which have the extra support of falsework, in the
shape of the structural material on which the coating rests. Asbestine
pulp, a natural product and one of our most important natural
reinforcing pigments, serves not only in the coarse group as supporting
particles for the linoxin arch, but also because of its peculiar
properties serves the more important purposes of reinforcement. It
retains, no matter how finely ground, its peculiar needle-like, or
rod-like, form of particles, and obviously serves the purpose of
reinforcing the flat arch of linoxin, exactly as iron bars or iron
netting serve in reinforced concrete arches. The medium sized particles
of the second group of pigments produced by chemical alteration or
precipitation, serve the purpose of the broken rock in concrete, and
together with the coarser supporting particles and the finest
reinforcing particles, give minimum voids and a maximum imperviousness
to agencies of internal decay.

"It goes without saying that the pigments of any one group contain
particles of dimensions which fall into the other two groups, but no one
pigment supplies the correct proportion of each of the three required
dimensions, and each pigment has so large a percentage of approximate
dimensions as to bar it from exclusive use in the other two groups.
Given similar homogeneous coatings under identical conditions, we
recognize the law that elasticity will vary directly with thickness.
Direct deduction from this law teaches us that of two paint coatings
equal in wear, in strength, opaqueness, and in all other qualities
except thickness, we should choose the thinner coating. Therefore if we
have two paint coatings fulfilling every requirement, the first
compounded with pigments giving a thicker coating and the second with
pigments yielding a thinner coating, we must choose the second formula
and obtain the thinner coating.

=Adhesive Power.= "The adhesion of the linoxin to the coarse group of
particles and to the underlying material is vital to the life of the
paint coating. If the coating parts from the surface beneath, we have
scaling or peeling. It is universally admitted that this will result
from use of zinc oxide as the sole pigment. We have only to conceive of
our flat arch of reinforced linoxin and leave out our points of support,
to realize that this is the inevitable result if the coating be subject
to extreme exposure, although good results may be obtained from zinc
oxide used alone, as, for instance, in interior house painting where
extreme changes of temperature and exposure are avoided.

"Three major lines of force hold our linoxin in place--adhesion toward
the underneath surface, adhesion to the coarse particles, and cohesion
within the linoxin itself. These lines must be represented by a flat
arch of linoxin with a downward pointing magnet therefrom, to represent
adhesion to the surface. Magnets on each side of the arch pointing
toward the supporting coarse particles, and two magnets within the arch
and pointing toward each other, or to the centre of the arch, these
latter to represent the force of cohesion."



CHAPTER VI

THE SCOPE OF PRACTICAL PAINT TESTS


=The Pigment Contention.= During the year 1906 officials of the North
Dakota Agricultural Experiment Station examined a number of paints on
sale in the northwestern States. The presence of large quantities of
inert pigments as well as water, in some of these paints, prompted
agitation for State laws requiring the formula-labeling of paints.
Certain paints made of white opaque pigments such as white lead and zinc
oxide were exempted from the statute. The white opaque pigments used in
these paints were believed by certain manufacturers as well as by many
prominent paint authorities of high standing to be benefited in their
wearing value by the addition of small percentages of inert crystalline
pigments, such as barytes, silica, China clay, etc. Laboratory
experiments had already determined that these inert crystalline pigments
had a certain definite action in increasing the life of paints, but it
had become evident that they should be used with discretion, in
moderation, and with a proper understanding of their limitations, if the
best results were to be obtained. The addition of very large quantities
of such pigments was not indulged in by discriminating manufacturers,
but the exact percentage to use was a matter of great doubt, even to the
most experienced. In order to determine just what percentage of
crystalline pigments, admixed with white opaque paint pigments, would
give the best service and results, it seemed imperative that practical
paint tests should be made. A series of paint tests on commercial brands
of paint had already been started at the Fargo Agricultural College,
and, at the suggestion of the Paint Manufacturers' Association of the
United States, another series of practical paint tests were instituted,
and carried out under the supervision of Dr. E. F. Ladd, Director of the
North Dakota Experiment Station.

=Test Fences to Solve the Problem.= It was apparent that the pigment
question could be solved only through field tests made on a
comprehensive basis and placed under the control of scientific and
technical societies of renown, so that they might be fair and unbiased
from every standpoint. In order to secure a comparison of the wearing of
different paint formulas in various sections of the country and under
differing climatic conditions, another series of tests was started in
the East soon after the North Dakota tests had been started.
Simultaneously fences were erected at Atlantic City, N. J., and
Pittsburg, Pa. The site of the Atlantic City fence is a strip of land
running due north from Atlantic and Savannah Avenues and within a short
distance from the Atlantic Ocean, the exposure being a severe one. The
site of the Pittsburg fence is back of the athletic field of the
Carnegie Technical Schools, the fence running east and west and being
exposed to the heavily charged sooty atmosphere coming from the many
industrial plants near by.

=Construction of Framework of Fences.= At these two locations framework
fences were built, upon which were placed a series of painted panels.
Heavy yellow pine posts six inches square were set in the ground about
six feet apart and to the depth of about four feet, upon a concrete
base. The posts were solidly tamped and then braced at the top with
supplementary studding braces two inches thick. Connecting the posts was
a line of studding six inches by two inches, forming a solid framework,
the bottom of which was approximately fifteen inches from the ground.
The bottoms and tops of the fences were protected by heavy boards two
inches thick, so that the moisture and rain might be prevented from
working itself up into the wood. The whole fence was sheathed with
twelve-inch planed white pine, thus forming a solid background for the
test panels.

=Lumber for Panels.= The lumber for the test panels was most carefully
selected, being of three grades--white pine, yellow pine, and cypress. A
large amount of each grade of lumber was secured, and after the best
portion had been made up into panels, the panels were inspected by an
expert lumber classer; nearly 40% being rejected on account of the
presence of knots or sappy places which appeared upon the surface. Each
of the panels finally passed upon as suitable for the test was branded
with a hot iron with consecutive numbers running from 1 to 186. The
grade of wood used for each panel was indicated by an abbreviated
mark--W for white pine, C for cypress, and Y for yellow pine. In order
that a record of each panel might be kept on file, previous to the
application of paint to the panels, a complete series of photographs was
taken of the panels in sets of four. This work seemed advisable so that
the future failure of paint on any one panel, which might be thought due
to faulty wood, could be either verified or refuted by a reference to
the series of photographs made of the bare panels.

[Illustration: View of Atlantic City Test Fence]

=Construction of Panels.= The panels were constructed of Dutch weather
boarding, tongued and grooved together in strips of three pieces and
capped at the top with a weather strip, forming a finished surface three
feet long and fifteen and a half inches high. They were firmly braced
together at their backs and nailed in such a manner that no portion of
the nails would appear on the surface of the panel, thus preventing the
staining of the panel from rust. The construction of the framework of
the fences at Atlantic City and Pittsburg was of such a nature that they
would each accommodate 560 panels of this type.

=Starting of Tests.= On account of the lateness of the season, it was
found necessary to do the painting of the tests within a building, so
that each formula might be subjected to fair and equal conditions of
application, thus excluding the blowing of dust or rain upon the painted
surfaces, which would have taken place had the panels been painted upon
the fence. The painting of the panels began in January, 1908, the
temperature within the buildings in which the work was done averaging 50
degrees Fahrenheit throughout the work.

It was decided to test each formula in three colors, in duplicate, and
on each grade of wood, exposing the duplicates on either side of the
fence. Thus for one paint formula there were required 18 panels, or 6
painted in each color and on 3 grades of wood.

=Paints for Tests.= The mixed paints received for the tests were in
quart cans, having been especially prepared from the formulas submitted
to manufacturers by the technical committee in charge of the work. They
were properly labeled with their number and color, in each case. The
formulas decided upon for the test are described later. The various
white leads and other single pigment paints which were used were
received in kegs weighing 12-1/2 pounds each, having been bought in the
open market and then given a formula number. The formulas of the paints
designed for both the Atlantic City and Pittsburg tests, as well as the
numbers of the panels upon which the paints were applied, are shown on
pages 131-133-145. The analysis of one of the combination paints applied
is herewith given, to show the correct method of stating the composition
of a paint.

FORMULA NO. 20, ATLANTIC CITY TEST FENCE

Percentage Composition

  ===================+=======+=======+=======+=======
                     |Pigment|Vehicle| Total |
  -------------------+-------+-------+-------+-------
  Corroded white lead| 67.01 |   --  | 42.84 |
  Zinc oxide         | 19.89 |   --  | 12.71 |
  Asbestine          |  3.86 |   --  |  2.47 |
  Calcium carbonate  |  9.24 |   --  |  5.91 |
  Raw oil            |   --  | 94.30 | 34.02 |
  Japan drier        |   --  |  3.89 |  1.40 |
  Turpentine         |   --  |  1.81 |  0.65 |
  -------------------+-------+-------+-------+-------
                     |100.00 |100.00 |100.00 |
  ===================+=======+=======+=======+=======

=Brushes.= Heavy 7-O round bristle brushes were used for the priming
coat so that the paint might be well worked into the wood, while for the
second and third coats three-inch chisel edge brushes were used. These
brushes were, of course, washed several times with turpentine after
painting each panel, so that pigments from one paint could not be
carried over into a paint containing other pigments.

[Illustration: Cypress Panels]

=Shellacking Panels.= The shellacking of any bad places of minor nature
which may have been present on the surfaces of some of the panels, was
done with the highest grade orange shellac. It was thought advisable to
determine whether shellacking over the priming coat of paint or on the
bare wood previous to the application of the priming coat, was the
better method. Panels Nos. 1 to 8 in each test were therefore shellacked
over the priming coat, while on all other panels the shellacking was
done directly on the bare wood previous to the application of the
priming coat of paint.

=Application of Paints.= In order to determine just how much paint was
applied to each panel and to reckon the spreading rate therefrom,
careful weighings were made during the application of every paint. This
was carried out by placing a quart can of paint as received, upon a
laboratory balance, the gross weight being taken and recorded. The can
was shaken and its contents transferred to a quart-size enameled cup
where with the aid of a paddle it was broken up into a mixture of even
consistency. A portion of this paint was then transferred to two small
sample cans carefully numbered with the formula number, for future
reference and analysis. The reduction of the paint was then made. The
brush used on the priming coat was placed with the pot and the paint on
the balance and the weight taken by the official weigher. The pot was
then given to the painter who applied the priming coat to one panel. The
brush, pot, and paint were then handed back to the official weigher and
the difference in weight recorded. From these data could be reckoned the
spreading rate of the formula applied.

The drying of the panels was noted every few hours and observations made
to determine whether the paints were penetrating properly into the
surface of the wood. A period of eight days was allowed between each
coat in order that thoroughly hard setting might take place.

During the application of the second coat of paint to the panels, fresh
cans of paint were used in every case so that fresh reductions could be
made of the proper consistency. Full data were also recorded on the ease
of application, working, and nature of drying shown, as well as
appearance presented by each paint after each coat had been applied. New
packages of paint were also used for the third coat, and, as a rule, the
paint was applied without reduction or with full oil reduction,
turpentine being eliminated in nearly every case for the third coat
work.

=Reductions.= The single pigment paints, such as white leads, were
reduced by the so-called ounce system, each ounce of oil added to 12-1/2
ounces of paste pigment representing one gallon of vehicle to one
hundred pounds of lead. A complete report of the reductions, spreading
rates, etc., used in the tests would take up three or four hundred pages
of printed matter. The reductions shown on the following formulas are,
however, fairly representative of the reductions used on the combination
and single pigment paints.

REDUCTIONS ON FORMULA NO. 2

_White and Yellow_

     1st Coat Condition when opened--good. Consistency when broken
     up--heavy. Reduction recommended by manufacturer--none. Reduction
     used--3 pints raw oil, 1 pint turps, 1 gallon paint. Consistency after
     reducing--good, stiff. Working--fair. Drying--fair on pines;
     cypress--poor. Penetration, pines--good; cypress--poor.

     2nd Coat Consistency when broken up--heavy. Reduction used--1-1/2
     pints turpentine, 1 pint boiled oil. Consistency after reducing--good.
     Working--good. Hiding--medium. Drying on pines--good; cypress--poor.
     One-half pint japan added to gallon of paint. Penetration--fair.

     3rd Coat Reduction used--1-1/2 pints oil, 1/2 pint turpentine.

     _Reductions for Lead Pastes_ Calculated on 100 lb. keg.

     Formulas Nos. 37-38. (Corroded White Lead.)

     1st Coat 6-1/2 gallons oil, 1/2 gallon turpentine, 1 pint turpentine
     japan.

     2nd Coat 3-1/2 gallons oil, 1 gallon turpentine, 1 pint japan.

     3rd Coat 3 gallons oil, 1 pint turpentine, 1/2 pint japan.

=Hiding Power of Paints.= When the priming coat had thoroughly dried on
each panel, the painter carefully stencilled a black Geneva cross over
the priming coat with lampblack in oil. The object of this black cross
was to make a determination of the comparative opacity or hiding power
of the different paints applied. It is well known that various pigments
when ground in oil differ in their hiding power in direct proportion to
the difference in the refractive indices of the pigments and oils used,
those containing high percentages of pigments such as white lead and
zinc oxide being superior in hiding power. After the second and third
coat of paint had been applied to each panel, there was evident a
remarkable difference in the hiding power, as the black cross showed
through in some cases quite clearly, while in other cases it was almost
completely hidden. The hiding power of a paint is one of the properties
which the master painter looks upon as most essential, but it should, of
course, be accompanied in a satisfactory paint by good spreading power
and longevity.

=Actinic Light Tests.= After the drying of all the paints, it was
decided that it would be of extreme interest to conduct a test on the
resistance of certain paints to actinic light. It is well known that the
ultraviolet or chemical rays of the sun are most energetic in causing
chemical reactions that result in the early decay of certain types of
paint. It was thought that the disintegrating effect of these rays, as
well as their effect in the bleaching out of colors, might be prevented
by placing upon certain panels small orange colored glass slides which
would prevent the passing of these rays to the painted surface. The
slides used were five inches long and three inches wide and were placed
upon the middle board of certain panels, with picture framing, putty,
and galvanized iron tacks. The preservation of the underlying surface
from the sun's rays would, it was thought, prevent the deterioration of
the paint, and at the same time preserve its original color so that it
might be compared to the color of the exposed portion at the time of
inspection.

=Supervision of Tests.= The Atlantic City tests were under the constant
supervision of Committee E of the American Society for Testing
Materials, this committee having accepted the inspection of the fence. A
representative was constantly present throughout the work in order to
see that each formula received fair treatment. The actual painting work
was under the supervision of the writer, together with a master painter
representing George Butler who was chosen by the Master Painters'
Association of Philadelphia as the official painter of the Atlantic
City test fence. Mr. J. B. Campbell of Chicago also acted as an official
of the Paint Manufacturers' Association in the application of the
formulas to both the Atlantic City and Pittsburg fences.

At Pittsburg the fence was placed directly under the supervision and
control of the Carnegie Technical Schools, who chose for the fence work
a committee of their technical force. Drs. James and Schaeffer of this
institution were present throughout most of the work and were constantly
represented during the test. The Pittsburg Master Painters' Association
appointed a committee consisting of Messrs. Dewar, Rapp, and Cluley, for
the actual painting work, and they were represented with the writer
throughout the tests.

Great interest was exhibited in the work by the committees in charge,
and the skill of the practical painters, combined with the care of the
inspectors, made the treatment of each formula fair and satisfactory.



CHAPTER VII

CONDITIONS NOTED AT INSPECTION OF TESTS


=Inspection of Atlantic City Tests.= During the month of March, just one
year after the placing of the painted panels on the Atlantic City fence,
an inspection was made jointly by a committee representing the Master
Painters' Association of Pennsylvania, the Scientific Section of the
Paint Manufacturers' Association of the United States, and certain
members of sub-Committee E of the American Society for Testing
Materials.

=Methods Used at Inspection.= One of the most important tests made when
inspecting paint is the determination of the chalking taking place.[19]
There was developed during the inspection of the Atlantic City panels a
new method for determining the comparative chalking of the various
paints. It was thought desirable to secure a method, if possible, that
would show results which might be photographed and even tabulated in
percentage form, if desired. The apparatus for the new test consisted of
a small strip of black felt three inches wide by five inches long,
placed across a small block of wood which would fit in the palm of the
inspector's hand. This outfit resembled a blackboard eraser and was used
in a similar way. By holding the apparatus firmly against the panel and
drawing it half-way across the panel in a straight line toward the
operator, there was obtained on the black cloth a white mark
proportional in intensity to the amount of chalking which had taken
place on the given area. When a series of these cloths were made, they
were assembled and photographed for comparison. It should be noted that
the above chalking test is useful only where the painted panels under
examination have been exposed over a period of one to two years, during
which period the chalking of paints has been shown to be greatest and
the chalked surface of a fairly adherent nature. Where longer exposures
have been made and where rains have removed from the painted panels a
considerable amount of the chalked pigment which has formed, such a test
would not be fairly representative of the amount of chalking which had
taken place.

  [19] Mr. Macgregor of the Picher Lead Co. has just developed a new
       test to determine the relative imperviousness of paints which
       have begun to chalk. He draws a mark about two inches long upon
       the painted surface with a fountain pen. The ink mark will spread
       rapidly to a wide area if the chalking is of a bad order. If the
       chalking is slight and the film in good condition, the ink mark
       will not spread.

[Illustration: Series of Black Felt Cloths used in making the Chalk
Tests on the Various Formulas. Numbers over Cloths represent Panels]

[Illustration: CHALKING.--Type of Decay Exhibited by Improperly Made
Paint (magnified view)]

[Illustration: CHECKING.--Type of Decay Exhibited by Improperly Made
Paint (magnified view)]

[Illustration: BLISTERING.--Type of Decay Exhibited by Improperly Made
Paint (magnified view)]

[Illustration: CRACKING.--Type of Decay Exhibited by Improperly Made
Paint (magnified view)]

[Illustration: GENERAL DISINTEGRATION.--Type of Decay Exhibited by
Improperly Made Paint (magnified view)]

[Illustration: SCALING.--Type of Decay Exhibited by Improperly Made
Paint (magnified view)]

=Gloss.= The gloss of the various panels was a condition which was also
reported upon, the middle board of each panel being washed with a wet
sponge one day before the inspection so that any surface dirt might be
removed. By looking at a panel from the side, a day after the washing,
the inspector was enabled to get a fair idea of the degree of gloss
exhibited by each formula.

=Hiding Power.= The hiding power of each paint was determined, as before
described, by observing the degree to which the stencilled lampblack
cross on the priming coat was visible through the second and third
coats. Single pigment paints such as white lead possessed very great
hiding power and obscured the black cross almost completely, while the
cross was quite visible through paints containing high percentages of
crystalline pigments.

=Checking.= The checking of each panel was determined by examining with
a small high-power hand glass magnifying fifteen diameters. It is well
known that examinations with such a hand glass will not determine
whether so-called fine matt checking is taking place, but it will
determine whether checking has appeared to any marked extent. Fine matt
checking is the first sign of the decomposition of a paint, and is
preliminary to the visible checking seen by the naked eye, which is
often followed by alligatoring. Examination of some formulas disclosed
this so-called alligatoring and even the exposed wood between the
fissured surface which had developed from what were at first fine hair
checks. It is, in the opinion of the writer, possible to predict with a
fair degree of accuracy by examination of a painted surface, one year
after exposure, how the paint will wear in the future and what its
appearance will be at the end of another year.

=Hardness.= The hardness of each panel could not be determined with any
degree of accuracy, but the inspectors were able to roughly determine
this condition by very close inspection. From practical experience of
the wearing of white lead and zinc oxide, and the comparative hardness
of these two pigments, zinc oxide was selected as the maximum for
hardness and termed number 10, while white lead was selected as the
minimum and termed number 1. The varying degrees of hardness exhibited
by the formulas were recorded in terms from one to ten. This comparison
of course was only an approximate one.

=General Condition.= The so-called general conditions of the panels was,
as a rule, the consensus of the judgment held by the various inspectors,
with due regard to such properties as chalking, checking, gloss, hiding
power, color maintenance, condition of surface, etc.



CHAPTER VIII

RESULTS OF ATLANTIC CITY TESTS


=Results on Various Woods.= On the Atlantic City Fence all the tests
made on yellow pine and cypress were found to be in an unsatisfactory
condition for a report, for in every case the sap and small knots
contained in such wood had a very bad effect upon the paint, causing
peeling and scaling. The white pine panels were in very much better
condition, and it was therefore decided to make the inspection entirely
from the white pine panels and in the future to remove the yellow pine
and the cypress panels from the fence and from the test. The Committee
advised that all future tests be made on white pine, as it is obviously
unfair to use anything but the highest grade wood for a paint test in
which the desire is to determine the comparative wearing value of
pigments.

     NOTE.--Recent tests have shown that Cypress may be successfully
     painted when the priming coat of paint is thinned with Benzol
     (Solvent Naphtha).

[Illustration: Panels on Atlantic City Fence Two Lower Sets of Panels
are painted with Lithopone Paints. Rapid Failure shown]

[Illustration: Panels on Atlantic City Fence]

[Illustration: Panels on Atlantic City Fence

Two Lower Sets of Panels are Painted with Combination Pigment Paints.
Excellent Results shown]

=Paints Containing Lithopone.= One of the most striking exhibitions of
paint disintegration in the whole test was the failure of nearly all the
lithopone formulas tested. At the time these formulas were suggested for
the test, various European technical journals had advocated the use of
lithopone in large percentage for paints to be used on exterior
surfaces. Good results had been obtained in the northwestern section of
Europe, with this pigment in certain mixtures, and the object of these
lithopone tests at Atlantic City and Pittsburg was to determine whether
satisfactory paints could be made of this pigment for exposure in this
country. Failure of the tests, however, in nearly every case except
where zinc oxide and whiting were mixed with the lithopone, indicated
that pigments such as zinc and whiting are necessary in order to prevent
the decomposition of lithopone pigment paints. The decay of lithopone
paints after they are applied seems to start with rapid oxidation of the
linseed oil, and this oxidation seems to continue in a progressive and
even accelerated way; after six months' exposure the surface of the
paint being chalked to a great extent and showing rapid decomposition of
the binder or vehicle. Inasmuch as lithopone is really an inert pigment,
this rapid decomposition of its vehicle cannot be explained in the same
way as the decomposition of the vehicle of pure white lead paints, where
the alkaline nature of the lead is probably responsible for the
formation of easily destroyed compounds. As complete failure had taken
place in nearly every case where lithopone had been used, it was decided
to condemn the lithopone panels on the fence, consisting of formulas 21
to 27, including panels 151 to 164 in white, panels 131 to 144 in
yellow, and 109 to 122 in gray. These lithopone tests were later on
replaced by new tests in 1909, which will be reported upon later in this
book.

=General Results.= From these tests, the inspectors reached the
unanimous conclusion that a paint made from any mixture of more than one
white opaque pigment, either when used alone or in combination with
small percentages of inert pigments, is far superior to any one single
pigment paint. It was found that the straight white lead paints failed
in every case, and this failure was so marked as to make it a conclusive
demonstration of the unfitness of white lead along the Atlantic coast,
when used without other pigments. Paints made with large percentages of
white lead, however, gave excellent results.

Gypsum was found unsafe to use in any large proportion in a paint,
because of its solubility and liability to percolate through the coating
of linoxyn or dried film, thus destroying the surface of the paint.
Whiting, or calcium carbonate, demonstrated that it could be used in
moderate percentage with some efficiency, but it was evident that any
great excess of this pigment must also be avoided on account of its
tendency towards rapid chalking. Magnesium silicate, aluminum silicate,
and silica are three inert pigments which proved to be of great value in
strengthening and reinforcing paints, especially when they were used in
small percentage. In the same way, black fixe and barytes, or barium
sulphate, also appeared to be useful in strengthening a paint. As these
two last named pigments are chemically the same but physically
different, the use of both in a paint formula is considered
advantageous, because of the differences in size and form of their
particles.

=Color Tests.= It was the unanimous conclusion of all the inspectors
that panels of all formulas which were tinted either gray or yellow were
showing far superior wear and less chalking and checking than those
which were painted in plain white. The reinforcing action of the tinting
materials must be credited for this lengthening of the wear of such
paints. Formulas 5, 6, 9, and 16, for instance, in the gray, were in
most excellent condition, and in these formulas were used ochre, umber,
bone-black, carbon-black, Venetian red and other inert bases. On the
yellow panels, formulas 5, 6, 9, and 16 were also in very superior
condition, and in these formulas chrome yellow and inert pigments were
also used.

Some of the color tests included the priming of boards with white lead,
zinc oxide, sublimed white lead, lithopone, and other single pigment
paints. Over these priming coats was placed a high grade brilliant
paranitraniline red. Fairly good results were obtained in every case,
but especially when lithopone or zinc oxide was used as a priming base.
These pigments seemed to have no effect upon the constitution of the
para red.

Prussian blue, a colored pigment largely used, but one liable to react
with certain paint pigments, was admixed with various paints applied to
certain panels. This color was found in some cases to have faded
materially, especially when mixed with alkaline pigments such as white
lead. Sublimed white lead and zinc oxide, which are more inert in
nature, did not have such action on Prussian blue, and the tinted bases
of these pigments stood up in a remarkable manner. The greens which were
tested were all in very good condition, with absence of fading, and
showing only slight mildew.

=Condensed Results of Inspection.= The results of inspection as obtained
by the fence committee[20] having in charge the inspection of the test,
have been condensed into table form, and are presented on pages 130-131.

  [20] R. S. Perry, Director Scientific Section, Paint Manufacturers'
       Association of the U. S.; George Butler, Official Painter,
       representing Master House Painters' & Decorators' Association, H.
       A. Gardner, Asst. Director.

=Second Annual Inspection of the Atlantic City Test Fence.= After the
original paints which had been applied to the Atlantic City Fence had
been exposed for over two years, another inspection was made by a
committee representing the Master Painters' Association of Philadelphia
and the Scientific Section of the Paint Manufacturers' Association of
the United States. A digest of the report of this committee[21] follows:

  [21] George Butler, Official Painter Atlantic City Test Fence,
       representing Philadelphia Master Painters' Association; Charles
       Macnichol, Master Painter; Henry A. Gardner, Director Scientific
       Section, Paint Manufacturers' Association of the U. S.

"The painted panels were all carefully inspected by the inspectors in
the usual manner. With the aid of high-power magnifying glasses,
checking was determined. The degree of chalking exhibited by the various
paints was ascertained by rubbing a piece of black cloth across the
surface of each paint. Close observance was made to determine scaling,
peeling, cracking, gloss, color, and the other factors to be considered
when examining a painted surface. From these observations it was
possible for the inspectors to state whether a panel exhibited general
good condition, general fair condition, or general poor condition.

CHART OF RESULTS--FIRST INSPECTION--ATLANTIC CITY TEST FENCE

  ==============================+=================================+
  Formula                       |         INERT PIGMENTS          |
  No.                           |---------------------------------|
    |Carbonate                  |Calcium                          |
    |Lead                       |Carbonate                        |
    |      |Zinc                |     |Calcium                    |
    |      |Oxide               |     |Sulphate                   |
    |      |      |Sublimed     |     |     |Magnesium            |
    |      |      |White        |     |     |Silicate             |
    |      |      |Lead         |     |     |     |Barium         |
    |      |      |      |Zinc  |     |     |     |Sulphate       |
    |      |      |      |Lead  |     |     |     |    |Silica    |
    |      |      |      |White |     |     |     |    |    |Blanc|
    |      |      |      |      |     |     |     |    |    |Fixe |
  --+------+------+------+------+-----+-----+-----+----+----+-----+
    |   %  |   %  |   %  |   %  |  %  |  %  |  %  |  % |  % |  %  |
   1| 30.0 | 70.0 |      |      |     |     |     |    |    |     |
   2| 50.0 | 50.0 |      |      |     |     |     |    |    |     |
   3| 20.0 | 50.0 | 20.0 |      |10.0 |     |     |    |    |     |
   4| 48.5 | 48.5 |      |      | 3.0 |     |     |    |    |     |
   5| 22.0 | 50.0 |      |      | 2.0 |     |26.0 |    |    |     |
   6|      | 64.0 |      |      |     |     |     |36.0|    |     |
   7| 37.0 | 63.0 |      |      |     |     |     |    |    |     |
   8| 38.0 | 48.0 |      |      |     |     |     |    |14.0|     |
   9|      | 73.0 |      |      |     |     | 2.0 |    |25.0|     |
  10| 44.0 | 46.0 |      |      | 5.0 |     | 5.0 |    |    |     |
  11| 50.0 | 50.0 |      |      |     |     |     |    |    |     |
  12| 60.0 | 34.0 |      |      |       6% Inert  Pigments        |
  13|      | 27.0 | 60.0 |      | 3.0 |     |10.0 |    |    |     |
  14| 25.0 | 25.0 | 20.0 |      | 5.0 |25.0 |     |    |    |     |
  15| 20.0 | 40.0 |      | 30.0 |10.0 |     |     |    |    |     |
  16| 33.0 | 33.0 |      |      |     |     |     |34.0|    |     |
  17| 40.0 | 40.0 |      |      |     |     | 3.0 |13.0|    | 4.0 |
  18| 75.0 | 25.0 |      |      |     |     |     |    |    |     |
  19|      | 25.0 | 75.0 |      |     |     |     |    |    |     |
  20| 67.0 | 19.5 |      |      |10.0 |     | 3.5 |    |    |     |
  33| 15.0 | 30.0 | 25.0 |      |     |     |     |    |30.0|     |
  34| 38.95| 33.58|  4.81|      |19.48|     | 3.18|    |    |     |
  35| 37.51| 25.87|  7.84|      |20.36|     | 8.42|    |    |     |
  36|100.0 |      |      |      |     |     |     |    |    |     |
  37|100.0 |      |      |      |     |     |     |    |    |     |
  38|100.0 |      |      |      |     |     |     |    |    |     |
  39|      |      |      |100.0 |     |     |     |    |    |     |
  40|      |      |100.0 |      |     |     |     |    |    |     |
  45|      |100.0 |      |      |     |     |     |    |    |     |
  46|      | 61.0 |      |      |     |     |     |39.0|    |     |
  47|      |100.0 |      |      |     |     |     |    |    |     |
  ==+======+======+======+======+=====+=====+=====+====+====+=====+

  ======================+==========+======+=========+======+
  Formula               |Panel     |Hiding|Color    |Hard- |
  No.                   |No.       |Power |         | ness |
    |First              |   |Condi-|      |         |      |
    |Coat               |   | tion |      |         |      |
    |   |Second         |   |      |      |         |      |
    |   |Coat           |   |      |      |         |      |
    |   |    |Third     |   |      |      |         |      |
    |   |    |Coat      |   |      |      |         |      |
    |   |    |    |Aver-|   |      |      |         |      |
    |   |    |    | age |   |      |      |         |      |
  --+---+----+----+-----+---+------+------+---------+------+
    |   |    |    |     |   |      |      |         |      |
   1|610| 987| 664|  754|  1|Good  |Good  |Excellent| 8    |
   2|913|1066| 948|  976|  3|Good  |Good  |Good     | 5    |
   3|912| 914| 786|  871|  5|Good  |Fair  |Good     | 4    |
   4|759| 939|1047|  915|  7|Good  |Good  |Good     | 5    |
   5|714|1000| 709|  808|  9|Good  |Weak  |Good     | 8-1/2|
   6|928|1189| 863|  993| 11|Fairly|Weak  |Good     | 8    |
    |   |    |    |     |   |Good  |      |         |      |
   7|763| 972| 891|  875| 13|Good  |Good  |Off Color| 7    |
   8|786| 910| 767|  821| 15|Good  |Good  |Good     | 8-1/2|
   9|716|1081| 812|  870| 17|Fair  |Poor  |Good     | 9    |
  10|861|1014| 862|  912| 19|Good  |Fair  |Good     | 5    |
  11|822| 959| 918|  900| 21|Good  |Good  |Excellent| 7-1/2|
  12|862| 965| 734|  854| 23|Good  |Medium|Good     | 4    |
  13|916|1031|1121| 1073| 25|Good  |Good  |Good     | 4    |
  14|564| 806| 785|  718| 27|Bad   |Medium|Good     | 5    |
  15|935|1044|1359| 1113| 29|Good  |Medium|Good     | 8-1/2|
  16|799| 903| 994|  899| 31|Fair  |Fair  |Good     | 7-1/2|
  17|806|1016| 884|  902| 33|Good  |Fair  |Good     | 4    |
  18|788|1257| 973| 1006|145|Good  |Good  |Excellent| 3    |
  19|700|1183|1400| 1094|147|Good  |Good  |Excellent| 2    |
  20|776|1063| 877|  905|149|Good  |Good  |Good     | 5    |
  33|512| 836| 689|  679|176|      |Fair  |         |      |
  34|523| 800| 810|  711|175|Good  |Medium|Good     | 4    |
  35|450| 893| 724|  689|180|Good  |Good  |Good     | 4    |
  36|408| 711| 861|  660|181|Bad   |Good  |Good     | 1    |
  37|524|1065| 828|  806|182|Bad   |Good  |Good     | 1    |
  38|555| 888| 794|  746|177|Bad   |Good  |Good     | 1    |
  39|550| 941| 916|  802|178|Good  |Fair  |Good     | 6    |
  40|643| 810| 998|  817|168|Good  |Good  |Good     | 2    |
  45|850|    |    |     |170|Fair  |Fair  |Good     | 9    |
  46|783|    |    |     |169|Fair  |Good  |Good     | 9    |
  47|730|    |    |     |172|      |Good  |Good     |10    |
  ==+===+====+====+=====+===+======+======+=========+======+

  ==============+===========+===========+===============================
  Formula       |           |           |
  No.           |           |           |
    |Checking   |Chalking   |Gloss      |Remarks
  --+-----------+-----------+-----------+-------------------------------
    |           |           |           |
   1|           |Very Slight|High       |Like rubbed varnish work.
   2|Hard Matt  |Moderate   |Med. High  |
   3|           |Medium     |Slight     |
   4|           |Very Slight|Med. High  |
   5|           |Slight     |High       |Hard surface.
   6|Matt       |           |Good       |Surface rough.
   7|           |Slight     |High       |
   8|           |Slight     |High       |
   9|Heavy Matt |Medium     |High       |Peeling started.
  10|           |Some       | Med. High |
  11|Med. Matt  |Some       |Med. High  |Some washing and discoloration.
  12|Heavy Matt |Bad        |Medium     |
  13|           |Medium     |Fair       |
  14|Evident    |Some       |Medium     |Dead, spongy, surface. White
    |           |           |           |incrustations.
  15|Coarse Matt|Slight     |High       |
  16|Bad        |Slight     |Good       |White incrustations.
  17|           |Some       |Fair       |
  18|Hard Matt  |Moderate   |Medium     |
  19|Hard Matt  |Slight     |Very Little|
  20|           |Very Little|Medium     |
  33|           |           |Good       |Rough surface.
  34|Evident    |Slight     |Egg Shell  |
  35|Matt       |           |Egg Shell  |
  36|Very       |Bad        |Egg Shell  |Same as 177, but
    |Apparent   |           |           |checking not so bad.
  37|Very       |Bad        |Egg Shell  |Same as 177 but wood
    |Apparent   |           |           |shows more plainly.
  38|Bad        |Bad        |Egg Shell  |Cracking and perishing evident.
  39|           |Some       |Good       |
  40|           |Consider-  |Egg Shell  |
    |           |able       |           |
  45|Very Evi-  |           |High       |
    |dent       |           |           |
  46|Some       |           |Good       |
  47|Apparent   |           |Good       |Indication of scaling.
  ==+===========+===========+===========+===============================

"An inspection of the white lead paints on the fence indicated in every
instance a rough, chalked, and disintegrated surface that seemed to be
well worn, in some cases nearly to the wood. The strongly oxidizing air
of the seacoast is probably responsible for the early decay of this
pigment.

"It was observed that the combination type of paint showed better hiding
power than white lead, over the black crosses placed on the priming coat
of each panel, as a hiding power test.

[Illustration: Front of Fence showing Present Rearrangement of Panels]

TESTS INAUGURATED IN 1907

CHART OF RESULTS OF SECOND ANNUAL INSPECTION OF ATLANTIC CITY TEST
FENCE, MAY, 1910

  =========================================================+
                           FORMULAS                        |
  --+------------------------+-----------------------------+
  F |                        |        INERT PIGMENTS       |
  o |                        +-----------------------------+
  r |Basic Carbonate         |Calcium                      |
  m |White Lead              |Carbonate                    |
  u |      |Zinc Oxide       |     |Calcium                |
  l |      |      |Basic     |     |Sulphate               |
  a |      |      |Sulphate  |     |  |Magnesium           |
    |      |      |White Lead|     |  |Silicate            |
  N |      |      |    |Zinc |     |  |    |Barium         |
  u |      |      |    |Lead |     |  |    |Sulphate       |
  m |      |      |    |White|     |  |    |     |Silica   |
  b |      |      |    --+   |     |  |    |     |   |Blanc|
  e |      |      |      |   |     |  |    |     |   | Fixe|
  r |      |      |      |   |     |  |    |     |   --+   |
  --+------+------+------+---+-----+--+----+-----+-----+---+
    |  %   |  %   |  %   |  %|  %  | %| %  | %   | %   |  %|
   1| 30   | 70   | --   | --| --  |--|--  |--   |--   | --|
   2| 50   | 50   | --   | --| --  |--|--  |--   |--   | --|
   3| 20   | 50   | 20   | --|10   |--|--  |--   |--   | --|
   4| 48.5 | 48.5 | --   | --| 3.0 |--|--  |--   |--   | --|
   5| 22   | 50   | --   | --| 2   |--|26  |--   |--   | --|
   6| --   | 64   | --   | --| --  |--|--  |36   |--   | --|
   7| 37   | 63   | --   | --| --  |--|--  |--   |--   | --|
   8| 38   | 48   | --   | --| --  |--|--  |--   |14   | --|
   9| --   | 73   | --   | --| 2   |--|--  |--   |25   | --|
  10| 44   | 46   | --   | --| 5   |--| 5  |--   |--   | --|
  11| 50   | 50   | --   | --| --  |--|--  |--   |--   | --|
  12| 60   | 34   | --   | --| --  |  6% Inert Pigment | --|
  13| --   | 27   | 60   | --| 3   |--|10  |--   |--   | --|
  14| 25   | 25   | 20   | --| 5   |25|--  |--   |--   | --|
  15| 20   | 40   | --   | 30|10   |--|--  |--   |--   | --|
  16| 33   | 33   | --   | --| --  |--|--  |34   |--   | --|
  17| 40   | 40   | --   | --| --  |--| 3  |13   |--   |  4|
  18| 75   | 25   | --   | --| --  |--|--  |--   |--   | --|
  19| --   | 25   | 75   | --| --  |--|--  |--   |--   | --|
  20| 67.0 | 19.5 | --   | --|10.0 |--| 3.5|--   |--   | --|
  33| 15   | 30   | 25   | --| --  |--|--  |--   |30   | --|
  34| 38.95| 33.58|  4.81| --|19.48|--|--  | 1.59| 1.59| --|
  35| 37.51| 25.87|  7.84| --|20.36|--|--  | 4.21| 4.21| --|
  36|100   | --   | --   | --|--   |--|--  |--   |--   | --|
  37|100   | --   | --   | --|--   |--|--  |--   |--   | --|
  38|100   | --   | --   | --| --  |--|--  |--   |--   | --|
  39| --   | --   | --   |100| --  |--|--  |--   |--   | --|
  40| --   | --   |100   | --| --  |--|--  |--   |--   | --|
  45| --   | 90   | --   | --|10   |--|--  |--   |--   | --|
  46| --   | 61   | --   | --| --  |--|--  |39   |--   | --|
  47| --   |100   | --   | --| --  |--|--  |--   |--   | --|
  ==+======+======+======+===+=====+==+====+=====+=====+===+

  ==+========================================+===
  F |                                        |
  o |                                        |
  r |                                        | P
  m |                                        | a
  u |                                        | n
  l |                                        | e
  a |                                        | l
    |          REPORT OF INSPECTION          |
  N +-----------+------------+------+--------+ N
  u |           |            |GENE- |        | u
  m |           |            |RAL   |        | m
  b |           |            |CON-  |        | b
  e |           |            |DI-   |        | e
  r |CHALKING   |CHECKING    |TION  |REMARKS | r
  --+-----------+------------+------+--------+---
   1|Very slight|Very slight |Good  |--      |  1
   2|Medium     |Slight      |Very  |--      |  3
    |           |            |good  |        |
   3|Medium     |Slight      |Good  |--      |  5
   4|Very slight|Slight      |Good  |--      |  7
   5|Slight     |Slight      |Good  |--      |  9
   6|Very slight|Slight      |Good  |--      | 11
   7|Medium     |Slight      |Good  |--      | 13
   8|Slight     |Very slight |Good  |--      | 15
   9|Very bad   |Deep, with  |Poor  |--      | 17
    |           |scaling     |      |        |
  10|Heavy      |Deep        |Medium|--      | 19
  11|Medium     |Medium      |Fair  |--      | 21
  12|Medium     |Deep        |Fair  |--      | 23
  13|Medium     |Slight      |Very  |--      | 25
    |           |            |good  |        |
  14|Medium     |Lateral     |Fair  |--      | 27
  15|Slight     |Visible with|Poor  |--      | 29
    |           |naked eye   |      |        |
  16|Slight     |Slight      |Good  |--      | 31
  17|Medium     |Slight      |Good  |--      | 33
  18|Medium     |Slight      |Very  |--      |145
    |           |            |good  |        |
  19|Consider-  |Deep        |Good  |--      |147
    |able       |            |      |        |
  20|Medium     |Slight      |Good  |--      |149
  33|Medium     |Slight      |Very  |--      |176
    |           |            |good  |        |
  34|Slight     |Slight      |Good  |--      |175
    |           |lateral     |      |        |
  35|Slight     |Lateral     |Good  |--      |180
  36|Consider-  |Heavy       |Fair  |Rough   |181
    |able       |            |      |surface |
  37|Consider-  |Heavy and   |Poor  |Rough   |182
    |able       |deep        |      |surface |
  38|More than  |Very deep   |Poor  |--      |177
    |Panel no.  |            |      |        |
    |182        |            |      |        |
  39|Consider-  |Very slight |Good  |--      |178
    |able       |            |      |        |
  40|Heavy      |Slight      |Good  |--      |168
  45|Slight     |Slight      |Good  |--      |170
  46|Slight     |Medium      |Fair  |--      |169
  47|None       |Very deep   |Poor  |--      |172
  ==+===========+============+======+========+===

"There are no pigments possessing greater hiding properties when first
used than white leads, but the lack of hiding power on the white lead
panels after two years' exposure was caused by the chalking away of the
lead. The superior hiding power of the composite paints was due to the
action of the other pigments in these combination paints in preventing
the lead from chalking away.

"The Committee finds that the addition of a reasonable percentage of
zinc oxide to white lead increases its durability and retards its
chalking, renders it whiter, and forms a surface that presents a much
better repainting condition. The combinations of white lead and zinc
oxide on the Atlantic City Test Fence were in general good condition
throughout.

"Corroded white lead, sublimed white lead, zinc oxide, and zinc lead are
the standard white opaque pigments. They were all tested on the Atlantic
City Fence and it was found that to use any one alone results in
inferior protection to the wood. Barium sulphate, silica, asbestine,
china clay, and calcium carbonate are the standard crystalline pigments.
In the past, the overloading of paints with these crystalline or inert
pigments has been the cause of the prejudice that painters have had
against their use. It has been established beyond controversy, however,
that the use of these pigments, in moderate percentage, combined with
any of the standard opaque white pigments, such as white leads, zinc
oxide, etc., undoubtedly results in better service from every standpoint
and forms the most satisfactory white paint for general outside use.
Some of the most perfect painted surfaces on the fence were those made
on the above basis as reference to the charted report will show."



CHAPTER IX

RESULTS OF PITTSBURG TESTS


The First Annual Inspection of the Pittsburg Test Fence took place
during May, 1909, a little over one year after the painted panels had
been placed in position. The inspectors found that in Pittsburg a heavy
deposit of soot had formed on the panels, and they considered it
therefore inadvisable to make a detailed report of the inspection until
the second year of the exposure. The general results of the Pittsburg
inspection as reported by the three committees[22] having supervision
over the work, is, however, given herewith.

  [22] J. H. James, Chairman Test Fence Committee, Carnegie Technical
       Schools.
       A. C. Rapp, Chairman Fence Committee, Pittsburg Branch
       Pennsylvania State Association of Master Painters.
       R. S. Perry, Director Scientific Section, Paint Manufacturers'
       Association of the U. S.; H. A. Gardner, Asst. Director.

[Illustration: Pittsburg Test Fence]

During the inspection of the Pittsburg tests it was decided to condemn
the lithopone panels on the fence, which consisted of formulas 21 to 27,
including panels 151 to 164 in white, 131 to 144 in yellow, 109 to 122
in gray. Almost complete failure had taken place in every case where
lithopone had been used. These lithopone tests were later on replaced by
new tests which are described later in this book.

"=Wood Most Valuable for Test.= As on the Atlantic City Fence, the white
pine panels afforded the best results and gives the best indication of
the comparative wearing of the paints and affords no unfair condition,
such as other woods might offer, to interfere with the test.

"=Condition of Cypress.= Cypress showed inferior conditions, except that
it was more pronounced and more discoloration of the panels was noticed
on this grade of wood, which seems to be extremely greasy in nature and
difficult to properly prime, even when the paint used upon this wood
contains a large percentage of volatile diluent.

"=Removal of Lithopone Panels.= The Joint Committees confirmed the
previous recommendation to remove all the lithopone formulas, and they
decided to remove the cypress and the yellow pine panels in every
formula except in the white paints.

"It was decided to reassemble all the white pine panels and group them
together for purposes of comparison, and in place of the panels
condemned and removed, to substitute a series of new formulas, to
further widen the scope of the tests.

"=Ultimate Value of Mixed Paints.= The results of the inspection
conclusively show that a mixture of more than one prime white pigment,
whether this mixture be alone or in combination with a small percentage
of inert pigment, produces a paint far superior to a paint manufactured
from one pigment alone.

"As a general statement of the comparative wearing of the paints, it
might be said that the composite formulas are less advanced toward
destruction than the paints made from single pigments such as
lithopones, white leads and zinc oxides. It is not to be understood from
this statement that it is the opinion of the committee that all of the
composite formulas are of equal value or that all of them are to be
recommended, but it is meant that the higher types, as evidenced by the
appearance of the panels, are in the above relation to the single
pigment paints.

[Illustration: Panels on Pittsburg Test Fence]

"=Lithopone Destroyed Rapidly at Pittsburg.= It was evident some time
ago that the formulas containing large percentages of lithopone were
rapidly failing, and their appearance was very much the same as those
formulas of a similar type at Atlantic City. There seems, however, to be
some difference in the way these formulas broke down; those on the
Pittsburg Fence having shown the quicker destruction, possibly due to
the action of the acid gases in the air upon the paint coating. This
further confirms the statement that paint compositions containing such
heavy percentages of lithopone and intended for outside use must be
designed with relation to the particular uses of the product and to the
climate in which they are to be used. It will also be necessary to
consider more carefully the vehicle of the paints which are to be made
of this pigment.

"=Possible Value of Excluding Vehicle for Lithopone.= It was the belief
of the committee that much better paints containing lithopone could be
designed by varying the percentages of the materials contained in the
formulas, and it was suggested that a less penetrable vehicle, made more
on the line of a varnish, and not as easily affected as straight
linoxyn, should be experimented with in connection with these lithopone
formulas.

"The success of certain European countries in using lithopone as a
pigment, even in a very high percentage, may be due to the use of a
special vehicle, and, if it is found in future tests that this material,
which has been reported as well suited in Northern European climates,
may be benefited and made of service by the addition of special oils and
special vehicles, then this test would be of great value to the whole
paint trade at large.

"Preliminary inspections were made on October 6th and later on December
12th, 1908, and a marked difference was observed at the two inspections
in the wearing of the various formulas.

"The lapse of the two months between these inspections gave opportunity
during which cold weather caused contraction of the paint film which had
been previously subjected to the hot summer sun, and caused marked
chalking of the white lead formulas. On October 6th this chalking was
just commencing, while in the December inspection it was well advanced,
and at the annual inspection, had proceeded to such an extent that the
pigment had been washed from the panels representing those paints which
had started early chalking.

"Panel 177, representing Zinc Lead, was found to be extremely dark in
color throughout the coating and was more on the order of a grayish
tint. It resisted all attempts to wash it down to a white surface. The
panel, however, in other respects, was in fairly good condition.

"=Condition of Corroded White Lead Panels.= Panel 174, representing Type
B Pure Basic Carbonate-White Lead, was very badly perished and
discolored, and an examination of the surface showed very bad checking.
Long continued washing with a sponge removed a discolored surface and
showed but a rather thin coating. Panel 175, representing Type C Pure
Basic Carbonate-White Lead, showed most marked checking and was in very
much the same condition as 174 and 176. Panel 176, representing Type A
Pure Basic Carbonate-White Lead, was in the same condition as the Type B
and C Basic Carbonate-White Leads.

"=Condition of Sublimed White Lead.= Panel 178, representing Sublimed
White Lead (Basic Sulphate-White Lead,) was chalking, and the paint coat
was somewhat disintegrated. The chalking present on this formula,
however, showed that the disintegration of the paint coat had not taken
place for several months after the Basic Carbonate-White Leads. This
panel maintained good color, not being acted upon by sulphur gases.

"=Blackening of Corroded White Lead.= The black and gray formation on
all the Basic Carbonate-White Lead panels was probably due to the action
of sulphur gases which are present in the district immediate to
Pittsburg, and which may cause the formation of black sulphide of lead.

"Possibly a general conclusion from all these panels might be described
as a perishing of the paint coating, with the formation of sulphide of
lead which to a certain extent protects the coating beneath it, but the
perishing has proceeded to such an extent that the unaltered paint
coating left is but a slight protection to the wood, being extremely
thin.

"The committee resolved that the detailed observations of the panels
could not be made and that they would not be justified in making
detailed comparisons between the various formulas, giving the gloss,
hardness, general condition, checking, etc. Precision in this work at
such a time was impossible, and it was decided that a further period
would have to elapse before such a detailed comparison could be made
between the various blended or composite formulas on the fence.

"=Report on Colors.= It was resolved that at the next inspection of the
Pittsburg Fence, portions of the original samples of the original paints
used for the yellows and grays should be on hand, previously painted out
on small panels for comparison for the deterioration of the colors on
these same panels on the fence.

"An examination of the combination formula grays by the committee led to
the general conclusion that those grays which did not contain a very
large percentage of white lead were superior in their maintenance of
tone and tint and general condition to any of the other grays upon the
fence. However, the presence of umber, ochre, and red oxide in some of
the grays which showed to the best advantage may account for their
permanence of tone. Some of these grays were the so-called warm grays
and were much darker in tone and tint than the ordinary drab which is
generally applied.

"The straight pure Basic Carbonate-White Lead paints were not painted
out in grays or yellow, the test upon this material being only in white.

"On Panels 120 and 126, which represent formulas 6 and 9 respectively,
the grays are in most excellent condition, and it will be found, by
reference to formulas 6 and 9, that there is an absence of white lead in
their composition. These formulas, however, contained a small percentage
of umber and ochre. Formulas 5 and 16 contained over 20% White Lead and
the gray of these formulas maintained their blue tone very well. These
formulas were tinted solely with lampblack.

"An inspection of Panel 138, which represents Formula 15, showed good
maintenance of color in the gray, and was in much better condition as
regards permanence of color than the other grays containing white lead.

"A study of the yellow panels on the fence led to the unanimous
conclusion that a liberal amount of Basic Carbonate-White Lead seemed to
have a beneficial result in preserving the bright tone of the chrome
yellow in tints so strong as those used on the fence. It was noted that
Panel 108, which represents Formula 28, and in which zinc yellow was
used, showed great permanence of tone and tint. Unfortunately this zinc
chromate was added to a formula containing a large percentage of
lithopone, and the destruction of the lithopone to a great extent
affected the value of this test.

[Illustration: Whiteness of Sublimed White Lead

Darkness of Corroded White Lead

On Pittsburg Test Fence]

"=Maintenance of Para Reds.= A study of the paranitraniline or azo reds
painted over the various pigments as priming coats demonstrated that the
reds on this fence are in better condition than the reds at Atlantic
City. As is well known, para red is manufactured by precipitation in an
acid solution and is best maintained under acid conditions. The acidity
of the Pittsburg atmosphere, caused by the large amount of acid gases
which are being poured into the air, day in and day out, and which are
constantly condensing on the surface of structures, may account for the
better preservation of these reds.

"It was noted that the para reds which were applied to panels prime
coated with white lead seemed to be brightening in color and seemed to
be gradually working over toward a lightening which may in the future
show a pinkish tint.

"=Report on Greens.= The bronze green is in most excellent condition and
shows an absence of the mildew appearance which was observed at Atlantic
City.

"The chrome green is standing up exceedingly well, there being
practically no change whatsoever in the color since it was exposed.

"=Best Base for Blues.= An inspection of the blues showed that those
which gave the greatest permanence and the least amount of fading were
applied in combination with either Sublimed White Lead (Basic
Sulphate-White Lead), or zinc oxide, while those blues which were
applied in combination with Basic Carbonate-White Lead showed marked
failure and were completely bleached out, due, of course, to the
alkaline nature of the corroded white lead; Prussian blues being
transformed by alkalies to a white compound.

"=Superior Value of Composite Formulas.= Some of the mixed leads, or
so-called graded leads, which are combinations of white leads with other
high-grade pigments and containing some inert pigments, were not
deteriorated so far as the white lead formulas, and the general
conclusion was that they were upward of six months behind the
deterioration of the straight white leads, and this was confirmed by the
presence of moderate chalking, showing an excellent repainting surface
and a better thickness and condition of the paint coating.

"The same conclusions which were reached at Atlantic City, as to the
best method of shellacking, obtained also on the Pittsburg Fence,
namely, that application of the shellac to the wood previous to the
first coat is the better method.

"=Analysis of Paints.= At the time of the painting of the fence a sample
of each paint was placed in small friction top cans, carefully labeled,
and sent to the Carnegie Technical Schools' laboratory for analysis.
The analyses of these paints were made by members of the Test Fence
Committee, representing the schools, and appear in this bulletin. The
results obtained conform very closely to the formulas which were applied
to the fence, a variance of only one or two per cent. being shown in the
amount of the different pigments."

=Second Annual Inspection of Pittsburg Test Fence.= The second annual
inspection of the Pittsburg Test Fence was made on Thursday, May 7th,
1910. The panels in Pittsburg after having weathered for over two years
presented an appearance which allowed the making of a detailed
inspection, this having been found impossible during the first annual
inspection. The inspection party[23] included those master painters who
represented the Pittsburg Master Painters' Association, who were in
charge of the application of the paints in 1907, 1908, and 1909,
together with the test fence committee from the faculty of the Carnegie
Technical Schools, and representatives of the Scientific Section. A
summary of the report issued by this committee follows:

  [23] A. C. Rapp, Chairman, Test Fence Committee, Pittsburg Branch,
       Master Painters' Association; John Dewar, member Fence Committee,
       Pittsburg Branch, Pennsylvania State Association of Master
       Painters; J. H. James, Chairman, Carnegie Technical Schools' Test
       Fence Committee; John A. Schaeffer, member Test Fence Committee,
       Carnegie Technical Schools; Henry A. Gardner, Director Scientific
       Section, Paint Manufacturers' Association of the U. S.

"Two of the members of the inspection party have been impressed with the
lumber lottery existing in some field tests, which have been conducted,
and feel that when the object of a test is to determine the relative
value of paints, such tests should be conducted on a standard grade of
wood, such as white pine. The use of cypress, pitch pine, and other
faulty woods, is often the cause of the failure of a paint, which on
good wood would show up well. For this reason, only the white pine
panels painted with white paints were considered in the inspection, the
yellow pine panels and cypress panels having been thrown out of the test
at last year's inspection.

"Checking, cracking, and alligatoring on the painted surfaces were
determined by using a magnifying glass. The degree of chalking existing
was decided upon by using small pieces of black felt cloth, rubbing
them against the surface of the panel; the degree of whiteness removed
upon the cloth being indicative of the amount of chalking taking place.
General condition was decided upon after carefully weighing the opinion
of each member of the inspection party, as regards the general
characteristics shown by each paint, such as checking, chalking,
scaling, condition for repainting, hiding power, etc. The results have
been charted and presented in this manner:[24]

  [24] An endeavor was made to use uniform terms in reporting on each
       formula. In some cases it was necessary to bring out more
       forcibly the condition by the insertion of qualifying remarks.

[Illustration: Panel on Left Painted with Single Pigment Paint; Panel on
Right Painted with Combination Pigment Paint. Photograph taken after Two
Years' Exposure on Pittsburg Test Fence]

"=Conclusions Reached from the Test.= The primary object of the test
made at Pittsburg was to determine whether a combination paint, made of
two or more pigments, would be equal or superior to single pigment
paints. After one year's exposure, the combination type of paint proved
more durable than the single pigment paints.

"It was early apparent that the combination type of paints, that is,
those paints made of more than one pigment, indicated in most cases very
excellent wear, with a minimum of blackness and a general good condition
of surface.

TESTS INAUGURATED IN 1907

CHART OF RESULTS OF SECOND ANNUAL INSPECTION OF PITTSBURG TEST FENCE,
MAY, 1910

  =========================================================+
                            FORMULAS                       |
  --+------------------------+-----------------------------+
  F |                        |        INERT PIGMENTS       |
  o |                        +-----------------------------+
  r |Basic Carbonate         |Calcium                      |
  m |Wh. L'd                 |Carbonate                    |
  u |      |Zinc Oxide       |     |Calcium                |
  l |      |      |Basic     |     |Sulphate               |
  a |      |      |Sulphate  |     |  |Magnesium           |
    |      |      |Wh. L'd   |     |  |Silicate            |
  N |      |      |    |Zinc |     |  |    |Barium         |
  u |      |      |    |Lead |     |  |    |Sulphate       |
  m |      |      |    |White|     |  |    |     |Silica   |
  b |      |      |    --+   |     |  |    |     |   |Blanc|
  e |      |      |      |   |     |  |    |     |   | Fixe|
  r |      |      |      |   |     |  |    |     |   --+   |
  --+------+------+------+---+-----+--+----+-----+-----+---+
    |  %   |  %   |  %   |  %| %   | %| %  | %   | %   | % |
   1| 30   | 70   | --   | --|--   |--|--  |--   |--   |-- |
   2| 50   | 50   | --   | --|--   |--|--  |--   |--   |-- |
   3| 20   | 50   | 20   | --|10   |--|--  |--   |--   |-- |
   4| 48.5 | 48.5 | --   | --| 3.0 |--|--  |--   |--   |-- |
   5| 22   | 50   | --   | --| 2   |--|26  |--   |--   |-- |
   6| --   | 64   | --   | --|--   |--|--  |36   |--   |-- |
   7| 37   | 63   | --   | --|--   |--|--  |--   |--   |-- |
   8| 38   | 48   | --   | --|--   |--|--  |--   |14   |-- |
   9| --   | 73   | --   | --| 2   |--|--  |--   |25   |-- |
  10| 44   | 46   | --   | --| 5   |--| 5  |--   |--   |-- |
  11| 50   | 50   | --   | --|--   |--|--  |--   |--   |-- |
  12| 60   | 34   | --   | --|--   |   6% Inert Pigment    |
  13| --   | 27   | 60   | --| 3   |--|10  |--   |--   |-- |
  14| 25   | 25   | 20   | --| 5   |25|--  |--   |--   |-- |
  15| 20   | 40   | --   | 30|10   |--|--  |--   |--   |-- |
  16| 33   | 33   | --   | --|--   |--|--  |34   |--   |-- |
  17| 40   | 40   | --   | --|--   |--| 3  |13   |--   | 4 |
  18| 75   | 25   | --   | --|--   |--|--  |--   |--   |-- |
  19| --   | 25   | 75   | --|--   |--|--  |--   |--   |-- |
  20| 67.0 | 19.5 | --   | --|10.0 |--| 3.5|--   |--   |-- |
  33| 15   | 30   | 25   | --|--   |--|--  |--   |30   |-- |
  34| 38.95| 33.58|  4.81| --|19.48|--|--  | 1.59| 1.59|-- |
  35| 37.51| 25.87|  7.84| --|20.36|--|--  | 4.21| 4.21|-- |
  36|100   | --   | --   | --|--   |--|--  |--   |--   |-- |
  37|100   | --   | --   | --|--   |--|--  |--   |--   |-- |
  38|100   | --   | --   | --|--   |--|--  |--   |--   |-- |
  39| --   | --   | --   |100|--   |--|--  |--   |--   |-- |
  40| --   | --   |100   | --|--   |--|--  |--   |--   |-- |
  45| --   | 90   |--    | --|10   |--|--  |--   |--   |-- |
  46| --   | 61   |--    | --|--   |--|--  |--   |39   |-- |
  47| --   |100   |--    | --|--   |--|--  |--   |--   |-- |
  ==+======+======+======+===+=====+==+====+=====+=====+===+

  ==+========================================+===
  F |                                        |
  o |                                        |
  r |                                        | P
  m |                                        | a
  u |                                        | n
  l |                                        | e
  a |                                        | l
    |          REPORT OF INSPECTION          |
  N +-----------+------------+------+--------+ N
  u |           |            |GENE- |        | u
  m |           |            |RAL   |        | m
  b |           |            |CON-  |        | b
  e |           |            |DI-   |        | e
  r |CHALKING   |CHECKING    |TION  |REMARKS | r
  --+-----------+------------+------+--------+---
   1|Slight     |None        |Good  |Slight  |  2
    |           |            |      |scaling;|
    |           |            |      |fairly  |
    |           |            |      |white   |
    |           |            |      |surface |
   2|Medium     |Very slight |Fair  |Panels  |  4
    |           |            |      |quite   |
    |           |            |      |dark and|
    |           |            |      |some    |
    |           |            |      |scaling |
   3|Consider-  |None        |Good  |Fairly  |  6
    |able       |            |      |white   |
   4|Consider-  |Lateral and |Fair  |White   |  8
    |able       |irregular   |      |surface |
   5|Medium     |Very        |Very  |Extreme-| 10
    |           |slight      |good  |ly white|
    |           |            |      |surface |
   6|Very slight|Very bad;   |Poor  |Black   | 12
    |           |rough sur-  |      |surface |
    |           |face        |      |        |
   7|Slight     |Slight      |Good  |Medium  | 14
    |           |            |      |white   |
    |           |            |      |surface |
   8|Slight     |Slight      |Good  |White   | 16
    |           |            |      |surface;|
    |           |            |      |slight  |
    |           |            |      |scaling |
   9|None       |Deep;       |Very  |Film    | 18
    |           |peeling in  |poor  |brittle |
    |           |places      |      |and sur-|
    |           |            |      |face    |
    |           |            |      |dark    |
  10|Medium     |Slight la-  |Good  |Surface | 20
    |           |teral in    |      |very    |
    |           |places      |      |white   |
  11|Consider-  |Deep matt   |Fair  |Consi-  | 22
    |able       |checking    |      |derable |
    |           |            |      |scaling;|
    |           |            |      |forma-  |
    |           |            |      |tion of |
    |           |            |      |black   |
    |           |            |      |coating |
    |           |            |      |shat-   |
    |           |            |      |tered   |
    |           |            |      |off     |
  12|Medium     |Slight      |Fairly|Surface | 24
    |           |            |good  |white   |
  13| Medium    |None        |Excel-|Very    | 26
    |           |            |lent  |white   |
  14|Consider-  |Medium      |Fair  |Panel   | 28
    |able       |            |      |fairly  |
    |           |            |      |white   |
  15|Slight     |Medium      |Good  |Surface | 30
    |           |            |      |quite   |
    |           |            |      |dark    |
  16|Medium     |Very slight |Good  |Quite   | 32
    |           |            |      |white   |
  17|Consider-  |Slight,     |Fair  |Surface | 34
    |able       |along       |      |fairly  |
    |           |lateral     |      |white   |
    |           |lines       |      |        |
  18|Medium     |Slight, with|Good  |Surface | 36
    |           |some scaling|      |has be- |
    |           |            |      |come    |
    |           |            |      |quite   |
    |           |            |      |dark    |
  19|Consider-  |None        |Excel-|No black| 38
    |able       |            |lent  |coating;|
    |           |            |      |surface |
    |           |            |      |very    |
    |           |            |      |white,  |
    |           |            |      |due to  |
    |           |            |      |inert-  |
    |           |            |      |ness of |
    |           |            |      |pigment |
    |           |            |      |or pro- |
    |           |            |      |gressive|
    |           |            |      |chalking|
  20|Medium     |Medium      |Good  |        | 40
  33|Heavy      |None        |Fair  |White   |168
    |           |            |      |surface |
  34|Consider-  |Very slight |Good  |Surface |172
    |able       |            |      |is very |
    |           |            |      |white;  |
    |           |            |      |progres-|
    |           |            |      |sive    |
    |           |            |      |chalking|
    |           |            |      |may have|
    |           |            |      |prevent-|
    |           |            |      |ed for- |
    |           |            |      |mation  |
    |           |            |      |of black|
    |           |            |      |coating |
  35|Bad        |None        |Good  |Very    |173
    |           |            |      |white;  |
    |           |            |      |no black|
    |           |            |      |coating |
    |           |            |      |evident |
  36|Bad        |Bad         |Fair  |Surface |174
    |           |            |      |is dead |
    |           |            |      |black;  |
    |           |            |      |shatter-|
    |           |            |      |ed in   |
    |           |            |      |places  |
  37|Extremely  |Medium      |Fair  |Very    |175
    |bad        |            |      |black   |
    |           |            |      |surface |
    |           |            |      |and     |
    |           |            |      |mottled |
    |           |            |      |in      |
    |           |            |      |places  |
  38|Very bad   |Very bad,   |Poor  |Black   |176
    |and quite  |with scaling|      |surface |
    |dusty      |            |      |is loose|
    |           |            |      |and     |
    |           |            |      |shatter-|
    |           |            |      |ed      |
  39|Consider-  |Slight      |Good  |Panel   |177
    |able       |            |      |surface |
    |           |            |      |quite   |
    |           |            |      |white   |
  40|Very bad   |Slight      |Good  |Surface |178
    |           |            |      |very    |
    |           |            |      |white,  |
    |           |            |      |possibly|
    |           |            |      |due to  |
    |           |            |      |progres-|
    |           |            |      |sive    |
    |           |            |      |chalking|
    |           |            |      |or in-  |
    |           |            |      |ertness |
    |           |            |      |of pig- |
    |           |            |      |ment    |
  45|Slight     |Considerable|Fair  |White   |169
    |           |            |      |surface |
  46|Slight     |Slight      |Fair  |Consi-  |170
    |           |            |      |derable |
    |           |            |      |scaling |
    |           |            |      |present;|
    |           |            |      |surface |
    |           |            |      |fairly  |
    |           |            |      |white   |
  47|Bad        |Bad         |Bad   |Bad con-|171
    |           |            |      |dition  |
    |           |            |      |through-|
    |           |            |      |out     |
  ==+===========+============+======+========+===

[Illustration: Middle white panel is painted with a combination pigment
formula

Middle white panel is painted with pure Corroded White Lead

Notice Difference in Color after Two Years' Wear]

"=Recommendation.= On account of the peculiar conditions which obtain in
and around Pittsburg, as exemplified by these tests, the committee
finds, as a result thereof, that the best white paint for general
exterior use is made of white lead combined with zinc oxide and a
moderate percentage of inert pigments, such as silica, asbestine, or
barytes.

"=Some Peculiar Conditions Affecting the Tests.= The inspectors were
most impressed during the inspection by the blackness exhibited to such
a high degree by certain panels, and the fair degree of whiteness by
others. It is well known that in Pittsburg nearly all paints become
darkened by the deposition on their surface of carbon particles
emanating from the combustion of soft coal. Certain of the paints,
however, presented fairly white surfaces, and it would thus appear that
the extreme darkness shown by other paints was due to their composition.
Corroded white lead when used alone was uniformly covered by black
particles, and the higher the percentage of corroded white lead in a
paint the darker was the surface. It was at first thought that this
darkness was due to the softness of the white lead pigment or to its
roughened surface, in causing adherence of soot particles. Sublimed
white lead, however, which is also a soft pigment, chalked even more
progressively than corroded white lead, but its surface was not rough,
and presented a very white appearance. Scrapings from the different
panels are being taken, and after a careful analysis the findings from
the investigations will be reported by a member of the Inspection
Committee."

  A. C. RAPP.        _Chairman Test Fence Committee, Pittsburg Branch,
                     Master Painters' Association_

  JOHN DEWAR.        _Member Fence Committee, Pittsburg Branch, Penna. State
                     Association of Master Painters_

  J. H. JAMES.       _Chairman Carnegie Technical Schools' Fence Committee_

  J. A. SCHAEFFER.   _Instructor in Chemical Practice, Carnegie Technical
                     Schools Pittsburg, Pa._

  H. A. GARDNER.     _Director Scientific Section, Paint Mfrs. Asso. of U. S._

_May 31, 1910_


PITTSBURG TEST FENCE

COMPARATIVE SPREADING RATES OF WHITE PAINT ON WHITE PINE PANELS

_Average Spreading Rate 266 Square Feet_

  =======+===========+===========+===========+==========+==============
  Formula|First Coat |Second Coat|Third Coat | Average  |Spreading Rate
  Number | (sq. ft.) |(sq. feet) | (sq. ft.) |Spreading |    Rate
         |           |           |           |  Rate    | 3-Coat Work
         |           |           |           |(sq. feet)| (sq. feet)
  -------+-----------+-----------+-----------+----------+--------------
    1    |   759     |  1020     |    768    |   849    |   283
    2    |   694     |   975     |   1229    |   966    |   322
    3    |   743     |   873     |    770    |   795    |   265
    4    |   537     |   987     |   1019    |   848    |   283
    5    |   509     |   896     |    886    |   764    |   255
    6    |   765     |  1045     |    994    |   935    |   312
    7    |   734     |   922     |    996    |   884    |   295
    8    |   565     |   862     |    854    |   760    |   253
    9    |   622     |   926     |   1160    |   903    |   301
   10    |   610     |  1013     |   1070    |   900    |   300
   11    |   651     |   933     |   1010    |   865    |   288
   12    |   675     |  1027     |    623    |   775    |   258
   13    |   663     |   892     |    981    |   845    |   282
   14    |   498     |   785     |    807    |   697    |   232
   15    |   688     |  1000     |    984    |   891    |   297
   16    |   669     |   880     |    860    |   803    |   268
   17    |   635     |   982     |   1077    |   900    |   300
   18    |   636     |   959     |   1031    |   875    |   292
   19    |   626     |  1076     |   1037    |   913    |   304
   20    |   591     |  1015     |    929    |   845    |   282
   21    |   595     |   948     |    910    |   818    |   273
   22    |   617     |   868     |    810    |   765    |   255
   23    |   549     |  1002     |    986    |   846    |   282
   24    |   539     |   918     |    783    |   747    |   249
   25    |   530     |   929     |    850    |   770    |   257
   26    |   532     |   916     |   1011    |   820    |   273
   27    |   520     |   850     |    656    |   675    |   225
   33    |   600     |  1340     |    810    |   917    |   306
   34    |   471     |   743     |    690    |   635    |   212
   35    |   402     |   598     |    645    |   548    |   183
   36    |   398     |   668     |    838    |   635    |   212
   37    |   579     |   653     |    838    |   690    |   230
   38    |   463     |   615     |    704    |   594    |   198
   39    |   474     |   954     |    849    |   759    |   253
   40    |   446     |   815     |    871    |   711    |   237
   45    |   527     |   841     |    916    |   761    |   254
   46    |   605     |   740     |    818    |   721    |   240
   47    |   735     |   961     |    993    |   896    |   299
  =======+===========+===========+===========+==========+==============



CHAPTER X

A LABORATORY STUDY OF TEST PANELS


=Panel Sections for Laboratory Test.= In order to make a laboratory
study of the painted panels on the Atlantic City and Pittsburg fences,
it was thought advisable to remove small sections from representative
areas and transfer them to the laboratory for such work. The fences were
visited by the official inspection committees soon after the first
annual inspection, and the panels were carefully looked over. Upon each
was marked out a representative portion, care being exercised to select
areas where previous inspections had not disturbed the surface of the
film in any manner. The inspectors then placed the number of the panel
upon the areas which had been marked off, as well as their initials. The
marked sections were sawed out, wrapped in tissue paper, and then
transferred to the laboratory where they were placed upon models of the
respective fences from which they had been removed. The illustration
shows the model test fences set up together. It is very apparent that
the Pittsburg panels are much the darker in color, due to the soot, and
in some cases lead sulphide formed upon their surfaces. This difference
was undoubtedly due to the atmospheric conditions prevailing where the
tests were made. One would be led to suppose that a paint film exposed
to an atmosphere such as is found in Pittsburg would show deterioration
more rapidly than one exposed in Atlantic City. In all the tests and
experiments, however, the Atlantic City panels appeared broken down to a
much greater extent; though it is true that the Pittsburg panels had
darkened considerably and presented a rather mottled appearance. The
deposit of soot on the Pittsburg panel seemed to act as a preservative
coating for the film beneath, and prevented marked disintegration.

[Illustration: Sections of Atlantic City and Pittsburg Fences Arranged
for Laboratory Examination]

[Illustration: Sections of Atlantic City and Pittsburg Fences]

[Illustration: Upper set of tests made on Panels from Atlantic City
Fence

Lower set of tests made on Panels from Pittsburg Fence

Figures at left indicate Formula Number

Figures at right indicate Degree of Chalking]

[Illustration: Color Standard used in Comparison of Panel Section]

=Chalking Test.= Small strips of black felt, about one inch square, were
firmly attached to a block of wood, and by a clamp having the same
pressure in each case, the wood with its surface of black felt was fixed
to the panel. This apparatus, which resembles a blackboard eraser, is
firmly drawn across the panel in one direction for a certain definite
distance, during which time it gathers all the chalked surface presented
by the painted wood. Upon detaching the apparatus from the panel it is
observed that the black cloth becomes whitened to an extent
proportionate to the chalking that has taken place on the given area.

After each one of the panels had been treated in the same manner by the
same operator, the black cloths were assembled on one large board and
photographed. A definite standard of chalking was made up, and the
operator was enabled to put down opposite the report on each panel the
degree of chalking which had taken place, No. 1 representing the least
amount and No. 10 the greatest amount of chalking.

=Degree of Whiteness Shown by Panels.= It was a very simple matter to
gauge the whiteness of the various panels, by comparing them with a
series of standard boards painted with three coats of white paint.
Florence Brand, New Jersey zinc oxide, was used as the standard for
whiteness and termed "No. 1." In making "No. 2" standard, to the zinc
oxide was added .01% of lampblack. By adding .02% of lampblack to the
zinc, standard "No. 3" was obtained, and so on, increasing the amount of
lampblack in each case by .01%. These standards were run up to "No. 30,"
and the various panels on the different fences compared with them. The
degrees of whiteness are recorded in progressive numbers, No. 1 being
the standard for whiteness and No. 30 the darkest. The Atlantic City
panels ranged from 3 to 8 in the scale of whiteness, while the Pittsburg
panels required the use of the entire range of standards.

=Resistance to Abrasion.= The apparatus used for determining the
abrasion resistance of a paint was made of a glass tube about six feet
long, having an internal bore of 7/8 inch. This was supported in an
upright position over a dish which held the panel under test at an angle
of 45 degrees. The abrasive material consisted of No. 00 emery, which
was dropped into the tube through a funnel having a bore of 5 mm. When
the emery reached the bottom of the long tube it scattered itself so as
to strike a surface on the panel about an inch in diameter. The emery
was constantly poured in until the paint coating had worn away, showing
the bare wood. The weight in pounds of emery powder required to show the
disruption of the coating is recorded and reported as the measure of the
"abrasion resist." The panel requiring the greatest weight of emery to
cause abrasion is evidently the most resistant to abrasion. Paint is
often subjected to serious abrasion, through the blowing of sand,
especially at the seashore, and to withstand such action should contain
a proportion of pigments especially resistant to abrasion, such as
silica, zinc oxide, asbestine, and barytes.

[Illustration: Apparatus for Determining the Abrasion Resistance of
Paints]

[Illustration: Formula No. 1, A. C.]

[Illustration: Formula No. 2, A. C.]

[Illustration: Formula No. 3, A. C.]

[Illustration: Formula No. 4, A. C.]

[Illustration: Formula No. 5, A. C.]

[Illustration: Formula No. 6, A. C.]

     NOTE: The author wishes to acknowledge the assistance of Dr. J.
     A. Schaeffer in the preparation of the photomicrographs herewith
     shown.

[Illustration: Formula No. 7, A. C.]

[Illustration: Formula No. 8, A. C.]

[Illustration: Formula No. 9, A. C.]

[Illustration: Formula No. 10, A. C.]

[Illustration: Formula No. 11, A. C.]

[Illustration: Formula No. 12, A. C.]

[Illustration: Formula No. 13, A. C.]

[Illustration: Formula No. 14, A. C.]

[Illustration: Formula No. 15, A. C.]

[Illustration: Formula No. 16, A. C.]

[Illustration: Formula No. 17, A. C.]

[Illustration: Formula No. 18, A. C.]

[Illustration: Formula No. 19, A. C.]

[Illustration: Formula No. 20, A. C.]

[Illustration: Formula No. 33, A. C.]

[Illustration: Formula No. 34, A. C.]

[Illustration: Formula No. 35, A. C.]

[Illustration: Formula No. 36, A. C.]

[Illustration: Formula No. 37, A. C.]

[Illustration: Formula No. 38, A. C.]

[Illustration: Formula No. 39, A. C.]

[Illustration: Formula No. 40, A. C.]

[Illustration: Formula No. 45, A. C.]

[Illustration: Formula No. 46, A. C.]

[Illustration: Formula No. 47, A. C.]

=Making Photomicrographs.= The photomicrographs which are herewith shown
were made in the following manner: A part of a panel was placed upon the
stage of the microscope and held firmly in place with clips. By varying
the adjustment and carefully running over the field the condition of the
surface was readily given, using the same eye-piece and objective
throughout the tests, and obtaining a magnification of thirty-three.
Great care was exercised to secure an average field showing the general
and typical appearance of every panel. Little difficulty was experienced
in so doing, as the laboratory panels gave very representative surfaces
of the large panels on the fence. The instrument was then inclined
horizontally and the eye-piece was fitted into the camera nose. In the
back of the bellows of the camera was placed the ground glass for
focusing. To secure illumination the light from an electric arc lamp
was reflected from a mirror directly upon the painted surface of the
panel, which in turn was reflected through the camera on to the ground
glass. The plate-holder was then put in position and six-second
exposures were made, afterward developing and printing.

=Checking and Cracking.= What was termed "fine matt checking" at the
First Annual Inspection was not visible at the time to certain members
of the Inspection Committee, but it is an established fact that the
checking was an existing condition, as the photomicrographs have shown.
This checking has a very peculiar characteristic in that the lines are
very narrow and hair-like, being somewhat interlaced and peculiarly
forked. That this hair matt checking is a preliminary condition which
afterwards develops into matt checking and into marked or heavy checking
seems to be indicated.

It appears from an examination of the photomicrographs of the paint
films that a paint coating closely resembles the surface of the earth,
and is subject to the same basic laws that have caused the various
geodetic changes in the earth's crust. Observation of a dried pond or
lake bed will disclose types of fissuring and cracking similar to those
shown by dried paint coatings in which the oil has been fully oxidized,
and especially in the case of paints containing pigments which act upon
the oil to produce compounds brittle in nature.

At Atlantic City the panels were all clean and free from dirt,
presenting continuous exposure of the films, and thus maintaining
conditions for active checking. At Pittsburg, soon after the panels
began to chalk, the large amount of dust and black soot in the
atmosphere completely covered the panels with a very thick, resistant
coating of carbon, which acted as a seal or protector, preventing
disintegration to a great extent. This coating was extremely hard to
remove, and photomicrographs, before and after removal of this coating
by rubbing with a damp cloth, failed to reveal marked checking on any of
the formulas except those made of strictly pure basic carbonate-white
lead. The checking, even on these, was not as marked as at Atlantic
City. It is presumed that after the chalking had taken place and the
chalked pigment had been washed from the panels, the gradually
increasing coat of carbon and lead sulphide had protected the panels
from checking, or possibly the atmosphere of Pittsburg, which in other
respects had deteriorated the panels to a greater extent than at
Atlantic City, did not have the extreme action in causing checking that
the Atlantic City atmosphere seemed to have effected.

[Illustration: Combination Formula No. 1, Pittsburg

BEFORE WASHING

Mottled surface due to external coating of impurities.]

[Illustration: AFTER WASHING]

[Illustration: Formula No. 4, Pittsburg

BEFORE WASHING]

[Illustration: AFTER WASHING]

[Illustration: Formula No. 38, Pittsburg

Basic Carbonate--White Lead Panels on Fence

BEFORE WASHING

Checking evident even through the outer covering of foreign matter.]

[Illustration: AFTER WASHING]

[Illustration: Formula No. 36, Pittsburg

Basic Carbonate--White Lead Panels on Fence

BEFORE WASHING

Peculiar network-like checking appearing through outer coat of
impurities.]

[Illustration: AFTER WASHING]

[Illustration: Formula No. 40, Pittsburg]

[Illustration: Formula No. 45, Pittsburg]

=Results on Combination Pigment Paints.= It will be noticed that the
checking on most of the combination pigment paints made of lead, zinc,
and inert pigments, was moderate, and in many cases of a fine order. It
has been observed that the percentage of zinc oxide in a paint is not
always a criterion upon which future checking may be judged. Nor could
it be said that the checking is dependent upon the percentage of basic
carbonate-white lead added to the paint. However, it appears that
scientific blending of the various pigments, with regard to their
physical properties in oil, such as their strength and elastic limit,
develops the greatest resistance to both cracking and checking.
Elasticity is vital, but strength must be combined therewith in order to
prevent disruptions of the paint coating. Paint films made of certain
inert pigments, when tested on the filmometer, were relatively high in
strength, but relatively low in elasticity. Such pigments, when used in
large percentage, form coatings which are hard and apt to crack. The
use, however, of these pigments in moderate percentages seems very
beneficial in overcoming the effect of using an excessive percentage of
white lead, or of zinc oxide.

=Results on White Lead Paints.= The maximum checking was observed on the
basic carbonate-white lead panels, the size of the checks in some cases
being several times larger than those on the other panels.

On some of the basic carbonate-white leads the checking was of a very
peculiar nature, consisting of very broad fissures in the paint coating,
disclosing the wood surfaces beneath. The type of checking existing was
also distinct in its structure, being hexagonal in shape. One of the
most marked features shown by the basic carbonate-white lead films was
the extreme roughness of their surfaces. This roughness is most likely
due to the excessive chalking which had taken place.

=Results on Silica and Barytes Paints.= The checking of paints very high
in silica resolved itself into fine hair-like lines which are generally
lateral to each other, and indicate a cracked appearance. The checking
of paints containing very high percentages of barytes was also of a
distinct nature, being generally forked in appearance and of no definite
striation.

=Surface Condition of Fume Pigment Paints.= The panels painted with
basic sulphate-white lead (sublimed white lead) showed complete absence
of checking. This was also true of the panels painted with zinc lead.
These are both fume products and are extremely fine in their physical
size, which may account for this condition. Although zinc oxide is made
in a similar manner, it gives a much harder paint coating than either of
the afore-mentioned pigments, and presents a surface which develops
considerable checking, generally of a medium order. The past theories
regarding zinc oxide, in which it has been maintained that zinc oxide
gives the maximum checking, are evidently incorrect, as the checking
found on the zinc oxide panels was not as marked or deep as the checking
on the basic carbonate-white lead panels; in fact, the checking might be
more in the line of a cracking, possibly due to the brittle nature of
the coating composed of straight zinc. This is especially true of zinc
paints containing insufficient oil.

=The Importance of the Physical Nature of Pigments.= It appears that
very fine grinding of materials, chosen for their characteristic
fineness, with the absence of any unfavorable physical condition or
chemical sensitiveness, are important factors in the making of a paint
to resist cracking or checking. The purity of the essential materials,
as well as the scientific compounding of these materials, with due
regard to the law of minimum voids, are great factors which enhance the
qualities of paints, greater, perhaps, than the variation of percentages
of the various pigments which go to make up a paint.



CHAPTER XI

ADDITIONAL TESTS AT ATLANTIC CITY AND PITTSBURG


A series of new test panels to take the place of those panels which were
condemned and subsequently removed from the Atlantic City and Pittsburg
fences, were painted and exposed during June, 1909. These new test
panels are of white pine, this wood having been selected by the joint
inspection committee as offering the best condition for future tests.
The method used in painting these panels was the same as in the previous
tests, together with the adoption of certain refinements in the
reductions, application, etc. Thirty-six formulas were selected with
careful regard to the percentage of components, including several paints
containing lithopone combined with whiting and zinc oxide,[25] two
pigments which gave promise of supporting the lithopone for outside use.
Some of these lithopone paints contained special vehicles which it was
thought would prevent the destructive action which lithopone seems to
have upon linseed oil. In order to obtain a criterion of the value of
the new formulas applied, as against the wearing of straight white
leads, the original white leads used in the previous tests were
included, and other brands were added. Each formula was painted out in
white, yellow, and gray, upon panels of white pine wood arranged in
sequence upon the fence, and properly identified. The customary opacity
test, in the form of a small black square, was stencilled over the
priming coat of each panel, as in the former tests. The composition of
the vehicle in all the new tests was standard, using pure linseed oil
with a small percentage of turpentine drier. The tints used in each
formula were secured at the time of application by the use of standard
colors, lampblack, and medium chrome yellow, using an approximate amount
for each formula.

  [25] A brief study of the theory of solutions (See Cushman and Gardner
       on "Corrosion and Preservation of Iron and Steel"), involving the
       modes of iron formation, will be invaluable to the student who is
       inquiring into the cause of the peculiar fogging of lithopone,
       with the idea in view of correcting this evil by physical or
       chemical treatment. Inasmuch as our observations thus far have
       led us to believe that the fogging of lithopone takes place in
       the presence of moisture, with the contributory and necessary
       action of chemically active rays from the sun or other source, it
       is fair to assume that under these conditions the insoluble
       molecule of zinc sulphide and barium sulphate reverts by
       intricate molecular disturbance and ionization back to the
       soluble barium sulphide and zinc sulphate from which the
       lithopone is formed by metathesis. If this be true, then the acid
       nature of these soluble salts is no doubt combated and overcome
       at the moment of formation by the basic nature of zinc oxide and
       calcium carbonate, which tend to ionize to an alkaline reaction.
       The value of zinc oxide and calcium carbonate in lithopone paints
       as detergents of blackness, has been demonstrated at both
       Atlantic City and Pittsburg." H. A. G.

[Illustration: Section of Fence Showing New Panels Recently Placed]

[Illustration: Appearance of 1909 Tests]

An inspection of these new tests was made during June, 1910, and the
results of the inspection are shown on pages 178 to 181. The results of
the inspection prove that it is unsafe to use lithopone in a paint
containing white lead of any type, early darkening and failure being
shown in every case where such a combination existed. The formulas in
the new test, which were properly balanced and which had a low
percentage of lithopone combined with zinc oxide and whiting, presented
in some cases very good surfaces. A rough, sandy surface, however, was
shown where lithopone was used in any great quantity.

TESTS INAUGURATED IN 1909

RESULTS OF INSPECTION OF ATLANTIC CITY TEST FENCE, MAY, 1910

  ===============================================+
                    FORMULAS                     |
  --+-----------------------+--------------------+
  F |                       |                    |
  o |                       |                    |
  r |Basic Carbonate        |                    |
  m |White Lead             |                    |
  u |    |Zinc Oxide        |                    |
  l |    |  |Basic Sulphate |                    |
  a |    |  |White Lead     |  INERT PIGMENTS    |
    |    |  |   |Precipi-   +--------------------+
  N |    |  |   |tated      |Calcium Carbonate   |
  u |    |  |   |White Lead |  |Silica           |
  m |    |  |   |   |Zinc   |  |   |Asbestine    |
  b |    |  |   |   |Lead   |  |   |  |China Clay|
  e |    |  |   |   |  |Li- |  |   |  |  |Barytes|
  r |    |  |   |   |  |tho-|  |   |  |  | |Blanc|
    |    |  |   |   |  -pone|  |   |  |  | +-Fixe|
  --+----+--+---+---+---+---+--+---+--+--+--+----+
    |  % | %|  %|  %|  %|  %| %|  %| %| %| %|  % |
   1| -- |--| 45| --| --| 40|15| --|--|--|--| -- |
   2| -- |--| 45| --| --| 40|--| 15|--|--|--| -- |
   3| -- |45| --| --| --| 45|10| --|--|--|--| -- |
   4| -- |--| 45| --| --| 45|10| --|--|--|--| -- |
   5| -- |40| --| --| --| 40|20| --|--|--|--| -- |
   6| -- |--| 45| --| --| 35|--| --|20|--|--| -- |
   7| 50 |--| --| --| 36| --|--| --| 2| 8| 4| -- |
   8| -- |--| 50| --| --| 36|--| --| 2| 8| 4| -- |
   9| -- |--| 50| --| --| 36|--| --| 2|--|12| -- |
  10| -- |36| 50| --| --| --|--| --| 2| 8| 4| -- |
  11| 28 |55| --| --| --| --|--| --| 3|--| 7|  7 |
  12| -- |55| 28| --| --| --|--| --| 3|--| 7|  7 |
  13| -- |60| --| --| --| 30|10| --|--|--|--| -- |
  14| -- |30| 30| --| --| 30|10| --|--|--|--| -- |
  15| -- |--| 60| --| --| 30|--| --|10|--|--| -- |
  16| -- |--| --| --| --|100|--| --|--|--|--| -- |
  17| -- |--| --| --| --|100|--| --|--|--|--| -- |
  18| 33 |33| --| --| --| --|--| 17|--|17|--| -- |
  19| 34 |33| --| --| --| --|--| 33|--|--|--| -- |
  20| 34 |33| --| --| --| --|--| --|--|33|--| -- |
  21|100 |--| --| --| --| --|--| --|--|--|--| -- |
    |[26]|  |   |   |   |   |  |   |  |  |  |    |
  22|100 |--| --| --| --| --|--| --|--|--|--| -- |
  23|100 |--| --| --| --| --|--| --|--|--|--| -- |
  24| -- |--|100| --| --| --|--| --|--|--|--| -- |
  25| -- |--| --| --|100| --|--| --|--|--|--| -- |
  26| -- |--| --|100| --| --|--| --|--|--|--| -- |
  27|100 |--| --| --| --| --|--| --|--|--|--| -- |
  28|100 |--| --| --| --| --|--| --|--|--|--| -- |
  29| 24 |45| 13| --| --| --|--| --|18|--|--| -- |
  30| 45 |--| --| --| --| 40|15| --|--|--|--| -- |
  31| 45 |--| --| --| --| 40|--| 15|--|--|--| -- |
  32| 45 |--| --| --| --| 35|--| --|20|--|--| -- |
  33| 50 |--| --| --| --| 36|--| --| 2|--|12| -- |
  34| 75 |--| 25| --| --| --|--| --|--|--|--| -- |
  35| 50 |--| 50| --| --| --|--| --|--|--|--| -- |
  36| -- |--| --| --| --| --|--|100|--|--|--| -- |
  ==+====+==+===+===+===+===+==+===+==+==+==+====+

  [26] This pigment on analysis proved to be zinc lead.

  ==+===============================================+==
  F |                                               |
  o |                                               |
  r |                                               | P
  m |                                               | a
  u |                                               | n
  l |                                               | e
  a |                                               | l
    |                                               |
  N |                                               | N
  u |                                               | u
  m |              REPORT OF INSPECTION             | m
  b |---------+---------+----------------+----------+ b
  e |CHALKING |CHECKING |GENERAL         |REMARKS   | e
  r |         |         |CONDITION       |          | r
  --+---------+---------+----------------+----------+--
   1|None     |None     |Rough surface,  |          | 1
    |         |         |but fair for re-|          |
    |         |         |painting        |          |
   2|None     |None     |Fair; rough sur-|          | 2
    |         |         |face and slight-|          |
    |         |         |ly dark         |          |
   3|Very     |Very     |Good; very white|          | 3
    |slight   |slight   |surface         |          |
   4|None     |None     |Rough surface   |          | 4
    |         |         |and slightly    |          |
    |         |         |dark            |          |
   5|Very     |Very     |Good; very white|          | 5
    |slight   |slight   |surface         |          |
   6|None     |None     |Rough surface;  |          | 6
    |         |         |dark            |          |
   7|None     |Very     |Good            |          | 7
    |         |slight   |                |          |
    |         |lateral  |                |          |
    |         |checking |                |          |
   8|Heavy    |Slight   |Excellent; very |          | 8
    |         |         |white           |          |
   9|Heavy    |Some     |Excellent; very |          | 9
    |         |         |white           |          |
  10|None     |Slight   |Good            |          |10
  11|None     |Slight   |Good; slightly  |          |11
    |         |         |dark            |          |
  12|None     |Slight   |Good            |          |12
    |         |lateral  |                |          |
  13|Very     |Consider-|Fair            |          |13
    |slight   |able     |                |          |
    |         |lateral  |                |          |
    |         |running  |                |          |
    |         |along    |                |          |
    |         |grain of |                |          |
    |         |wood     |                |          |
  14|Very     |Consider-|Fair            |          |14
    |slight   |able     |                |          |
    |         |lateral  |                |          |
    |         |running  |                |          |
    |         |along    |                |          |
    |         |grain of |                |          |
    |         |wood     |                |          |
  15|Heavy    |Slight   |Fair            |          |15
    |         |lateral  |                |          |
    |         |checking |                |          |
  16|Heavy    |Consider-|Dark color;     |          |16
    |         |able     |rough surface   |          |
  17|Consider-|Medium   |Better than No. |          |17
    |able     |         |16; not as rough|          |
    |         |         |or dark         |          |
  18|Very     |None     |Good            |          |18
    |slight   |         |                |          |
  19|Very     |Slight   |Good            |          |19
    |slight   |         |                |          |
  20|Very     |None     |Good            |          |20
    |slight   |         |                |          |
  21|Slight   |Slight   |Fair; rough     |          |21
    |         |         |surface         |          |
  22|Very     |Lateral  |Fairly good     |          |22
    |slight   |cracking |                |          |
  23|Medium   |Lateral  |Fair            |          |23
    |         |cracking |                |          |
  24|Slight   |Slight   |Good for        |          |24
    |         |cracking |repainting      |          |
  25|Medium   |None     |Good surface    |          |25
  26|Heavy    |Slight   |Fair; surface   |          |26
    |         |cracking |rough & dark    |          |
  27|Heavy    |Lateral  |Fair            |          |27
    |         |cracking |                |          |
  28|Medium   |Consider-|Poor; very      |          |28
    |         |able     |rough, dark     |          |
    |         |         |surface         |          |
  29|Slight   |None     |Good            |          |29
  30|Heavy    |Heavy    |Poor            |          |30
    |         |checking |                |          |
    |         |and alli-|                |          |
    |         |gatoring |                |          |
  31|None     |Alliga-  |Rough surface;  |          |31
    |         |toring   |dark            |          |
  32|Slight   |Medium   |Dark and rough  |          |32
    |         |         |surface         |          |
  33|Consider-|Slight   |Poor; dark      |          |33
    |able     |         |surface         |          |
  34|None     |None     |Fair; dark      |          |34
    |         |         |surface         |          |
  35|None     |Slight   |Fair; rough     |          |35
    |         |         |surface         |          |
  36|Extremely|Medium   |Fair            |Vehicle   |36
    |bad      |         |                |disinte-  |
    |         |         |                |grated;   |
    |         |         |                |spotted in|
    |         |         |                |places    |
  ==+=========+=========+================+==========+==

TESTS INAUGURATED IN 1909

RESULTS OF INSPECTION OF PITTSBURG TEST FENCE, MAY, 1910

  ===============================================+
                    FORMULAS                     |
  --+-----------------------+--------------------+
  F |                       |                    |
  o |                       |                    |
  r |Basic Carbonate        |                    |
  m |White Lead             |                    |
  u |    |Zinc Oxide        |                    |
  l |    |  |Basic Sulphate |                    |
  a |    |  |White Lead     |   INERT PIGMENT    |
    |    |  |   |Precipi-   +--------------------+
  N |    |  |   |tated      |Calcium Carbonate   |
  u |    |  |   |White Lead |  |Silica           |
  m |    |  |   |   |Zinc   |  |   |Asbestine    |
  b |    |  |   |   |Lead   |  |   |  |China Clay|
  e |    |  |   |   |  |Li- |  |   |  |  |Barytes|
  r |    |  |   |   |  |tho-|  |   |  |  | |Blanc|
    |    |  |   |   |  -pone|  |   |  |  | --Fixe|
  --+----+--+---+---+---+---+--+---+--+--+--+----+
    |  % | %|  %|  %|  %|  %| %|  %| %| %| %|  % |
   1| -- |--| 45| --| --| 40|15| --|--|--|--| -- |
   2| -- |--| 45| --| --| 40|--| 15|--|--|--| -- |
   3| -- |45| --| --| --| 45|10| --|--|--|--| -- |
   4| -- |--| 45| --| --| 45|10| --|--|--|--| -- |
   5| -- |40| --| --| --| 40|20| --|--|--|--| -- |
   6| -- |--| 45| --| --| 35|--| --|20|--|--| -- |
   7| 50 |--| --| --| 36| --|--| --| 2| 8| 4| -- |
   8| -- |--| 50| --| --| 36|--| --| 2| 8| 4| -- |
   9| -- |--| 50| --| --| 36|--| --| 2|--|12| -- |
  10| -- |36| 50| --| --| --|--| --| 2| 8| 4| -- |
  11| 28 |55| --| --| --| --|--| --| 3|--| 7|  7 |
  12| -- |55| 28| --| --| --|--| --| 3|--| 7|  7 |
  13| -- |60| --| --| --| 30|10| --|--|--|--| -- |
  14| -- |30| 30| --| --| 30|10| --|--|--|--| -- |
  15| -- |--| 60| --| --| 30|--| --|10|--|--| -- |
  16| -- |--| --| --| --|100|--| --|--|--|--| -- |
  17| -- |--| --| --| --|100|--| --|--|--|--| -- |
  18| 33 |33| --| --| --| --|--| 17|--|17|--| -- |
  19| 34 |33| --| --| --| --|--| 33|--|--|--| -- |
  20| 34 |33| --| --| --| --|--| --|--|33|--| -- |
  21|100 |--| --| --| --| --|--| --|--|--|--| -- |
  22|100 |--| --| --| --| --|--| --|--|--|--| -- |
    |[27]|  |   |   |   |   |  |   |  |  |  |    |
  23|100 |--| --| --| --| --|--| --|--|--|--| -- |
  24| -- |--|100| --| --| --|--| --|--|--|--| -- |
  25| -- |--| --| --|100| --|--| --|--|--|--| -- |
  26| -- |--| --|100| --| --|--| --|--|--|--| -- |
  27|100 |--| --| --| --| --|--| --|--|--|--| -- |
  28|100 |--| --| --| --| --|--| --|--|--|--| -- |
  29| 24 |45| 13| --| --| --|--| --|18|--|--| -- |
  30| 45 |--| --| --| --| 40|15| --|--|--|--| -- |
  31| 45 |--| --| --| --| 40|--| 15|--|--|--| -- |
  32| 45 |--| --| --| --| 35|--| --|20|--|--| -- |
  33| 50 |--| --| --| --| 36|--| --| 2|--|12| -- |
  34| 75 |--| 25| --| --| --|--| --|--|--|--| -- |
  35| 50 |--| 50| --| --| --|--| --|--|--|--| -- |
  36| -- |--| --| --| --| --|--|100|--|--|--| -- |
  ==+====+==+===+===+===+===+==+===+==+==+==+====+

  [27] This pigment on analysis proved to be zinc lead.

  ==+===============================================+==
  F |                                               |
  o |                                               |
  r |                                               | P
  m |                                               | a
  u |                                               | n
  l |                                               | e
  a |                                               | l
    |                                               |
  N |                                               | n
  u |                                               | u
  m |              REPORT OF INSPECTION             | m
  b +---------+---------+----------------+----------+ b
  e |CHALKING |CHECKING |GENERAL         |REMARKS   | e
  r |         |         |CONDITION       |          | r
  --+---------+---------+----------------+----------+--
    |         |         |                |          |
   1|Consider-|Slight   |Fair            |Dark in   | 1
    |able     |         |                |places.   |
    |         |         |                |Diffused  |
   2|Slight   |Bad      |Fair            |Dark in   | 2
    |         |         |                |places    |
   3|Medium   |None     |Good            |Darkening | 3
    |         |         |                |shown in  |
    |         |         |                |places    |
   4|Consider-|None     |Good            |Medium    | 4
    |able     |         |                |dark      |
   5|Slight   |None     |Good            |No exces- | 5
    |         |         |                |sive dark-|
    |         |         |                |ness      |
   6|Medium   |Slight   |Good            |Surface   | 6
    |         |         |                |fairly    |
    |         |         |                |white     |
   7|Medium   |None     |Excellent       |Whitest   | 7
    |         |         |                |surface of|
    |         |         |                |new tests |
   8|Extremely|Slight   |Fair            |Surface   | 8
    |bad      |         |                |darkening |
   9|Extremely|Slight   |Fair            |Not as bad| 9
    |bad      |         |                |as No. 8  |
  10|Slight   |None     |Good            |Excellent |10
    |         |         |                |surface;  |
    |         |         |                |very white|
  11|Slight   |None     |Excellent       |Surface   |11
    |         |         |                |fairly    |
    |         |         |                |white;    |
    |         |         |                |thin soot |
  12|Medium   |None     |Good            |Surface   |12
    |         |         |                |white     |
  13|Medium   |Very bad |Fair            |Slight    |13
    |         |in spots |                |darkening |
  14|Heavy    |Consider-|Fair            |Slight    |14
    |         |able     |                |darkening |
  15|Extremely|Slight   |Fair            |Fairly    |15
    |bad      |         |                |white     |
  16|Extremely|Advanced |Bad             |Surface   |16
    |bad      |and deep |                |rough with|
    |         |         |                |consider- |
    |         |         |                |able dis- |
    |         |         |                |integra-  |
    |         |         |                |tion and  |
    |         |         |                |much dark-|
    |         |         |                |ness      |
  17|Not as   |Less ad- |Fair            |Not as    |17
    |bad as   |vanced   |                |dark as   |
    |No. 16   |than No. |                |No. 16;   |
    |         |16       |                |slightly  |
    |         |         |                |mottled in|
    |         |         |                |places;   |
    |         |         |                |buff color|
  18|Very     |Practi-  |Fair            |Surface   |18
    |slight   |cally    |                |white     |
    |         |none     |                |          |
  19|Very     |None     |Good            |Surface   |19
    |slight   |         |                |fairly    |
    |         |         |                |white     |
  20|None     |None     |Good            |Surface   |20
    |         |         |                |fairly    |
    |         |         |                |white     |
  21|Slight   |Slight   |Fair            |Surface   |21
    |         |         |                |very rough|
    |         |         |                |and dark  |
  22|Medium   |Slight   |Fair            |Surface   |22
    |         |         |                |fairly    |
    |         |         |                |white     |
  23|Slight   |Bad      |Fair            |Surface   |23
    |         |         |                |rough and |
    |         |         |                |darkest on|
    |         |         |                |fence     |
  24|Bad      |None     |Good            |Surface   |24
    |         |         |                |white     |
  25|Slight   |None     |Good            |Fairly    |25
    |         |         |                |white     |
    |         |         |                |surface   |
  26|Medium   |Slight   |Fair            |Rough and |26
    |         |         |                |very dark;|
    |         |         |                |chalking  |
    |         |         |                |is dis-   |
    |         |         |                |rupting   |
    |         |         |                |black     |
    |         |         |                |coating   |
  27|Medium   |Slight   |Good            |Surface   |27
    |         |         |                |fairly    |
    |         |         |                |white     |
  28|Medium   |Deep;    |Poor            |Surface   |28
    |         |evident  |                |rough and |
    |         |without  |                |very dark |
    |         |glass    |                |          |
  29|Slight   |Slight   |Good            |Very white|29
    |         |         |                |surface   |
  30|None     |Slight   |Fair            |Color dark|30
  31|Very     |Advanced |Fair            |Color very|31
    |slight   |         |                |dark      |
  32|Extremely|Consider-|Fair            |Color very|32
    |slight   |able     |                |dark;     |
    |         |         |                |rough     |
    |         |         |                |surface   |
  33|Extremely|Slight   |Fair            |Surface   |33
    |slight   |         |                |dark and  |
    |         |         |                |rough     |
  34|Slight   |Deep     |Fair            |Surface   |34
    |         |         |                |medium    |
    |         |         |                |dark      |
  35|Consider-|Slight   |Fair            |Surface   |35
    |able     |         |                |medium    |
    |         |         |                |dark      |
  36|Extremely|None     |Fair            |Vehicle   |36
    |bad      |         |                |disinte-  |
    |         |         |                |grated,   |
    |         |         |                |leaving   |
    |         |         |                |very      |
    |         |         |                |white,    |
    |         |         |                |chalked   |
    |         |         |                |surface of|
    |         |         |                |pigment   |
  ==+=========+=========+================+==========+==



CHAPTER XII

NORTH DAKOTA PAINT TESTS


An inspection of the original test fence, erected and painted by the
North Dakota Agricultural College, on the grounds of the agricultural
Experiment Station at Fargo, was made by the inspection committee[28]
representing the Paint Manufacturers' Association of the United
States, on the 19th and 20th of November, 1909. The fence was erected
in 1906 and painted with commercial paints, procured in the open
market. The east side of the fence was built of soft pine and cedar
weather-boarding, such as is almost universally used on houses in that
locality, presenting a very good surface for test purposes, while the
west side was built largely of flat trimmed boards of hard pitch pine
which, unfortunately, contained knots, pitch pockets, and uneven
surfaces, causing to a greater or lesser extent cracking, scaling, and
bad general results on all paints applied thereto.

  [28] Henry A. Gardner, Director Scientific Section, Educational
       Bureau, Paint Manufacturers' Association of U. S.; George Butler,
       Master Painter; Charles Macnichol, Master Painter.

The fences built in 1907 and 1908 at the suggestion of the Paint
Manufacturers' Association, were inspected on the 20th, 21st, and 22nd
of November, 1909, and the detailed results of the inspection of all
these fences follow in this report. The same general conclusions as to
the woods represented in the 1906 fence also apply to the 1907 and 1908
fences, and because of the general bad quality of wood used on the
western exposure of all fences, the detailed reports were made only from
an examination of the eastern side of the fences, both on cedar and soft
pine.

The following general summary of the inspection and its results applies
to all the test fences on the grounds of the college and is the
unanimous conclusion drawn by the inspectors from this work:

[Illustration: North Dakota Test Fences]

[Illustration: Typical Sample of Hard Pine Trim Board Showing Knot and
Sappy Grain]

[Illustration: Test No. 13--1906 Fence

Complete Disintegration and Failure of Cheap Paint]

"Non-absorbent woods, difficult to penetrate, such as those on the west
side of the fences, would undoubtedly have given much better results had
they been painted with paints properly reduced to suit the nature of the
wood. This treatment seems to have been overlooked in the North Dakota
tests, and the painting of the hard pine boards was done with the same
consistency of mixtures and the same reductions as upon soft pine.
Scaling of course resulted. One of the chief purposes of the fences,
however, was to study the different types of wood, and compliance with
this desire resulted in the bad conditions herein noted. It has been
shown in many other field tests that adherence of paints to hard wood
surfaces can be obtained only by causing the priming coat to become
amalgamated with the woody fibre, by the use of a large percentage of
volatile diluent turpentine, benzole, asphaltum spirits, etc., to secure
penetration. If such treatment is omitted, failure soon results, as was
evidenced by the uniformly bad conditions presented by the paints on the
hard pine panels.

[Illustration: Pine Weatherboarding Showing Knots and Grain]

[Illustration: Condition of Lumber Affecting Paint, West Side 1906
Fence]

[Illustration: Hail-stone Abrasions on House Repainting Tests]

[Illustration: Hail-stone Effect, West Side of 1907 Test Fence]

"During July, 1908, a violent hailstorm occurred in Fargo, and left its
impression on nearly every wooden structure; in many cases deep dents
being made into the wood. The west side of the test fences, which
received the most injury from this storm, was covered with these dents
over almost its entire surface, causing cracks in the form of concentric
rings to appear on the abraded paint coatings. The bad condition of the
wood, improper method of applying priming coat, combined with the
hailstorm effect on the painted surfaces on the west side of the fences,
were undoubtedly responsible for the universal failure of the paints
thereon, and, for these reasons, the west side was eliminated from the
detailed inspection, only general observations of these tests being
made. These general observations, however, showed that paints Nos. 6 and
8 on the 1906 fence, and paints Nos. 8, 10, and 13 on the 1907 fence,
proved the most satisfactory on the western exposure.[29]

  [29] These formulas were the same as those respectively numbered on
       the Atlantic City and Pittsburg fences.

[Illustration: Peculiar Crystallization Effect on Section 41. New
Special Fence Paint Applied During Cold Weather]

"Ochre was tried out as a priming coat on several formulas, but it was
found to be most unsatisfactory, affecting the subsequent coats of paint
and causing early failure, as evidenced by broad checking,
discoloration, and general bad condition. These conditions also apply
to those panels on the 1908 fence coated with shellac as a primer.

"The colored formulas in every case showed a great superiority over the
same paints in white untinted, and demonstrated that a percentage of
color has a wonderful influence on the preservation of the paint
coating, reducing chalking, checking, and general disintegration. This
condition is probably due to the reinforcing value of the color pigments
used.

"It is safe to state that the combination formulas tinted yellow were of
better appearance than the corroded white leads tinted yellow, the
latter appearing quite dark in many cases.

"The wearing of the paints made solely from white lead and zinc oxide
seemed to indicate that a percentage of a third pigment, of an inert
nature, would have been beneficial.

"The high-type mixtures of pigments containing lead and zinc, with
moderate percentages of inert pigments, on good wood, were in most
excellent general condition; in fact, much superior to the single
pigment paints. Their surface exhibited only minor checking and moderate
chalking with good maintenance of color, and presenting surfaces well
adapted to repainting.

"The sublimed white lead was in fair condition, with very little
checking, and offering a fair repainting surface. The corroded white
lead was somewhat whiter than the sublimed white lead, but a careful
observation of the surface of the corroded lead revealed deep checking.

"It was clearly demonstrated, however, that in climates of the North
Dakota type, white lead alone is not entirely satisfactory. The addition
of zinc oxide to white lead forms paint that has proved much superior to
the white lead alone.

"It was conclusively demonstrated that mixtures of white lead and zinc
oxide, properly blended with moderate percentages of reinforcing
pigments, such as asbestine, barytes, silica and calcium carbonate, are
most satisfactory from every standpoint, and are superior to mixtures of
prime white pigments not reinforced with inert pigments.

"The white leads painted out on the 1908 fence exhibited different
degrees of checking, the mild-process lead and sublimed white lead which
presented the best surfaces, being free from checking, while the
old-process leads seemed to show very deep and marked checking, even
after one year's wear.

[Illustration: Corroded White Lead

Sublimed White Lead

Condition of Two White Leads on Two Grades of Wood]

[Illustration: Photomicrographic Apparatus and Method of Use]

CONDENSED REPORT OF INSPECTION OF "1906" TEST FENCE

FARGO, N. D., NOV. 19-23, 1909

_No gloss shown by any of the paints. Formulas in white on white pine
only included here, on east side of fence_

  ==+=========================================================================++
   T|                                     FORMULAS                            ||
   e+--------------------------------------------+----------------------------++
   s|                   PIGMENT                  |          VEHICLE           ||
   t+--------------------------------------------+----------------------------++
    |Corroded                                    |Linseed Oil                 ||
   N|White Lead                                  |    |Turp. and Drier        ||
   o|     |Sublimed                              |    |    |Japan Drier       ||
   .|     |White Lead                            |    |    |  |Water          ||
    |     |     |Zinc Oxide                      |    |    |  |    |Benzine   ||
    |     |     |    |Calcium                    |    |    |  |    |Drier     ||
    |     |     |    |Carbonate                  |    |    |  |    |    |Vola-||
    |     |     |    |    |Silica and            |    |    |  |    |    |tile ||
    |     |     |    |    |Silicates             |    |    |  |    |    |Oil  ||
    |     |     |    |    |   |Barium Sulphate   |    |    |  |    |    |     ||
    |     |     |    |    |   |    |Magnesium    |    |    |  |    |    |     ||
    |     |     |    |    |   |    |Silicate     |    |    |  |    |    |     ||
    |     |     |    |    |   |    |   |Clay and |    |    |  |    |    |     ||
    |     |     |    |    |   |    |   |Silica   |    |    |  |    |    |     ||
    |     |     |    |    |   |    |   |   |Bary-|    |    |  |    |    |     ||
    |     |     |    |    |   |    |   |   |tes  |    |    |  |    |    |     ||
    |     |     |    |    |   |    |   |   |and  |    |    |  |    |    |     ||
    |     |     |    |    |   |    |   |   |Sili-|    |    |  |    |    |     ||
    |     |     |    |    |   |    |   |   |cate |    |    |  |    |    |     ||
  --+-----+-----+----+----+---+----+---+---+-----+----+----+--+----+----+-----++
    |  %  |  %  |  % |  % |  %|  % |  %|  %|  %  |  % |  % | %|  % |  % |  %  ||
   1|100  | --  | -- | -- | --| -- | --| --|  -- | -- | -- |--| -- | -- | --  ||
   2| --  |100  | -- | -- | --| -- | --| --|  -- | -- | -- |--| -- | -- | --  ||
   3| 50  | --  |50  | -- | --| -- | --| --|  -- |90  |10  |--| -- | -- | --  ||
   4| --  | 60  |40  | -- | --| -- | --| --|  -- |90  | -- |10| -- | -- | --  ||
   5| 28.7| --  |71.3| -- | --| -- | --| --|  -- |93  | 7  |--| -- | -- | --  ||
   6| 40.2| --  |50.3| 4.1|5.4| -- | --| --|  -- |90.7| 9.3|--| -- | -- | --  ||
   7| 21.9| 21.9|45.8|10.4| --| -- | --| --|  -- |89.6| 9.7|--| 0.7| -- | --  ||
   8| 44.1| --  |46.0| 4.6| --| -- |5.3| --|  -- |86.0|12.6|--| 1.4| -- | --  ||
   9|                     In gray only   No report.                           ||
  10| 13.9| --  |34.9|26.8| --| -- | --| --| 24.4|72.2| -- |--|24.0| 3.8| --  ||
  11| 55.0| --  |15.2| -- | --| -- | --| --| 29.8|     Test not finished      ||
  12| --  |  5.1|25.0| -- | --| -- | --| --| 69.9| -- | -- |--| -- | -- | --  ||
  13| --  | --  |31.3|45.4| --|22.8| --|0.5|  -- |57.2| -- |--|16.1|26.7| --  ||
  14| 34.8|  5.4|59.2| -- | --| -- | --| --|  -- |86.0|13.7|--| 0.3| -- | --  ||
  15| --  | --  |64  | -- | --|36  | --| --|  -- |98  | -- |--| -- | -- |  2  ||
  ==+=====+=====+====+====+===+====+===+===+=====+====+====+==+====+====+=====++

  ==+==============================================
    |              REPORT OF CONDITION
    +--------+-----------+-------+-------+---------
   T|        |           |       |       |
   e|        |           |       |       |
   s|        |           |       |       |
   t|        |           |       |       |
    |        |           |       |       |
   N|        |           |       |       |CONDITION
   o|CHALKING|CHECKING   |HIDING |COLOR  |FOR RE-
   .|        |           |POWER  |       |PAINTING
  --+--------+-----------+-------+-------+---------
   1|Very bad|Extremely  |Good   |Good   |Only fair
    |        |deep       |       |       |
   2|Bad     |Very slight|Good   |Light  |Fair
    |        |           |       |yellow-|
    |        |           |       |ish    |
    |        |           |       |tint   |
   3|Medium  |Fine matt--|Good   |Fair   |Fair to
    |        |deep in    |       |       |good
    |        |places     |       |       |
   4|Medium  |Surface    |Good   |Good   |Fair
    |        |checking,  |       |       |
    |        |very slight|       |       |
   5|Slight  |Quite deep |Medium |Good   |Poor.
    |        |           |       |       |Coating
    |        |           |       |       |wrinkled
    |        |           |       |       |and hard
   6|Medium  |Slight     |Good   |Good   |Good
    |        |surface    |       |       |
    |        |checking   |       |       |
   7|Medium  |Surface    |Fair   |Good   |Slight
    |        |checking   |       |       |shelling
    |        |with slight|       |       |from wood
    |        |cracking   |       |       |
   8|Medium  |Very slight|  Good |Good   |Good
   9|        |           |       |       |
  10|Slight  |Very bad   | Bad condition throughout.
  11|        |           |       |       |
  12|Medium  |Medium     |Defici-|Good   |Shelling
    |        |           |ent    |       |from wood
  13|  Worst looking surface in North Dakota tests.
  14|Medium  |Slight     |Fair   |Good   |Good
    |        |surface    |       |       |
    |        |checking   |       |       |
    |        |and peeling|       |       |
  15|Slight  |Lateral    |Good   |Good   |Hard film
    |        |cracking   |       |       |
    |        |quite deep |       |       |
  ==+========+===========+=======+=======+=========

CONDENSED REPORT OF INSPECTION OF "1907" TEST FENCE

FARGO, NORTH DAKOTA, NOV. 19-23, 1909

  ===+==========================================================================
   T |                                  FORMULAS
   e +-------------------------------------------+------------------------------
   s |                  PIGMENT                  |           VEHICLE
   t +-------------------------------------------+------------------------------
     |Corroded White Lead                        |Linseed Oil
   N |    |Sublimed White Lead                   |    |Turpentine
   o |    |   |Zinc Oxide                        |    |Drier
   . |    |   |    |Calcium Carbonate            |    |    |Turpentine
     |    |   |    |   |Aluminum and             |    |    |and
     |    |   |    |   |Magnesium Silicate       |    |    |Japan
     |    |   |    |   |  |Barytes               |    |    |  |Water
     |    |   |    |   |  |  |Silica             |    |    |  |    |Turpentine
     |    |   |    |   |  |  |    |Inert         |    |    |  |    |and Benzine
     |    |   |    |   |  |  |    |  |Magnesium  |    |    |  |    |Japan Drier
     |    |   |    |   |  |  |    |  |Silicate   |    |    |  |    |  |Drier
     |    |   |    |   |  |  |    |  |   |Calcium|    |    |  |    |  |  |Vola-
     |    |   |    |   |  |  |    |  |   |Sul-   |    |    |  |    |  |  |tile
     |    |   |    |   |  |  |    |  |   |phate  |    |    |  |    |  |  |Oil
     |    |   |    |   |  |  |    |  |   |  |Zinc|    |    |  |    |  |  |  |[B]
     |    |   |    |   |  |  |    |  |   |  |Lead|    |    |  |    |  |  |  |
  ---+----+---+----+---+--+--+----+--+---+--+----+----+----+--+----+--+--+--+---
    1| 30 | --|70  |-- |--|--| -- |--|-- |--| -- |93  | 7  |--| -- |--|--|--|--
    2| 50 | --|50  |-- |--|--| -- |--|-- |--| -- |86  | -- |10| 4  |--|--|--|--
    3| 20 | 20|50  |10 |--|--| -- |--|-- |--| -- |90  | -- |--| -- |10|--|--|--
    4|48.5| --|48.5| 3 |--|--| -- |--|-- |--| -- |83  | -- |--| -- |17|--|--|--
    5| 22 | --|50  | 2 |26|--| -- |--|-- |--| -- |90  | -- |--| -- |--|10|--|--
    6| -- | --|64  |-- |--|36| -- |--|-- |--| -- |98  | -- |--| -- |--|--| 2|--
    7| 37 | --|63  |-- |--|--| -- |--|-- |--| -- |85  |13  |--| 2  |--|--|--|--
    8| 38 | --|48  |-- |--|--|14  |--|-- |--| -- |91  | 9  |--| -- |--|--|--|--
    9| -- | --|73  | 2 |--|--|25  |--|-- |--| -- |66  |--  |--|12  |22|--|--|--
   10| 44 | --|46  | 5 |--|--| -- |--|-- |--| -- |86.0|12.5|--| 1.5|--|--|--|--
   11| 50 | --|50  |-- |--|--| -- |--| 5 |--| -- |78  |22  |--| -- |--|--|--|--
   12| 60 | --|34  |-- |--|--| -- | 6|-- |--| -- |91  | 7  |--| 2  |--|--|--|--
   13| -- | 60|27  | 3 |--|--| -- |--|10 |--| -- |90  | -- |--| -- |--|10|--|--
   14| 25 | 20|25  | 5 |--|--| -- |--|-- |25| -- |90  | -- | 6| -- |--|--|--| 4
   15| -- | 20|40  |10 |--|--| -- |--|-- |--| 30 |90  | -- | 8| 2  |--|--|--|--
   16| 33 | --|33  |-- |--|34| -- |--|-- |--| -- |90  | -- |10| -- |--|--|--|--
   17|100 |(Type A)|-- |--|--| -- |--|-- |--| -- | -- | -- |--| -- |--|--|--|--
   18|100 |(  "  B)|-- |--|--| -- |--|-- |--| -- | -- | -- |--| -- |--|--|--|--
   19|100 |(  "  C)|-- |--|--| -- |--|-- |--| -- |   10 gal. oil   |--|--|--|--
     |    |        |   |  |  |    |  |   |  |    |    reduction    |  |  |  |
   20| -- |100| -- |-- |--|--| -- |--|-- |--| -- | -- | -- |--| -- |--|--|--|--
   21| -- | --|100 |-- |--|--| -- |--|-- |--| -- | -- | -- |--| -- |--|--|--|--
   22| -- | --| -- |-- |--|--| -- |--|-- |--|100 | -- | -- |--| -- |--|--|--|--
   23|100 |(Type C)|-- |--|--| -- |--|-- |--| -- | 5-1/2 gal. oil reduction for
     |    |   |    |   |  |  |    |  |   |  |    |           priming
   24| 37.|7. |25. |20.|--|--|8.42|  (Michigan Seal   | -- |--| -- |--|--|--|--
     | 51 |84 |87  |36 |  |  |    |   White Lead)     |    |  |    |  |  |  |
   25| 38.|4. |33. |19.|--|--|3.18|(Railway White| -- | -- |--| -- |--|--|--|--
     | 95 |81 |58  |48 |  |  |    |     Lead)    |    |    |  |    |  |  |  |
  200|15. | --|--  | 1.|--|--| -- |--| 1.|--|43. |32. | 4. |--| 1. |--|--|--|--
     |625 |   |    |875|  |  |    |  |250|  |750 |250 |000 |  |250 |  |  |  |
  ===+====+===+====+===+==+==+====+==+===+==+===+====+=====+==+====+==+==+==+===

  [B] = Benzine

  ===+=========+=========================================
   T |         |           REPORT OF CONDITION
   e |         +------------+------+------+--------------
   s |         |            |      |      |
   t |         |            |      |      |
     |         |            |      |      |
   N |         |            |      |      |
   o |         |            |      |      |
   . |         |            |      |      |
     |CHALKING |CHECKING    |HIDING|COLOR |CONDITION FOR
     |         |            |POWER |      |REPAINTING
  ---+---------+------------+------+------+--------------
    1|Medium   |Considerable|Fair  |Fair  |Poor surface;
     |         |with lateral|      |      |too hard
     |         |cracking    |      |      |
    2|Medium   |Considerable|Good  |Fair  |Rather poor
     |         |with lateral|      |      |
     |         |cracking    |      |      |
    3|Bad      |Medium--    |Good  |Good  |Fair
     |         |scaling some|      |      |
    4|Medium   |Considerable|Good  |Good  |Medium
     |         |with lateral|      |      |
     |         |cracking    |      |      |
    5|Slight   |Slight      |Good  |Good  |Good
    6|Medium   |Considerable|Medium|Medium|Fair
    7|Consider-|Present;    |Fair  |Fair  |Poor
     |able     |long cracks |      |      |
    8|Slight   |Surface     |Good  |Good  |Fair
     |         |checking    |      |      |
    9|Not      |Considerable|Medium|Good  |Medium
     |evident  |with lateral|      |      |
     |         |cracking    |      |      |
   10|Medium   |Very slight |Good  |Good  |Good
   11|Slight   |Lateral     |Fair  |Fair  |Fair
     |         |cracking    |      |      |
   12|Consider-|Present with|Fair  |Fair  |Not very good
     |able     |slight      |      |      |
     |         |cracking and|      |      |
     |         |scaling     |      |      |
   13|Medium   |Surface     |Good  |Good  |Good
     |         |checking    |      |      |
     |         |only        |      |      |
   14|Consider-|Considerable|Medium|Fair  |Medium; some
     |able     |with lateral|      |      |washing shown
     |         |cracking    |      |      |
   15|Medium   |Medium      |Good  |Good  |Medium
   16|Medium   |Slight; some|Fair  |Good  |Medium
     |         |shelling    |      |      |
   17|Bad      |Alligator-  |Good  |Fair  |Poor
     |         |ing; deep   |      |      |
     |         |checking    |      |      |
   18|Bad      |Alligator-  |Fair  |Fair  |Poor
     |         |ing; deep   |      |      |
     |         |checking    |      |      |
   19|Bad      |Deep        |Good  |Fair  |Poor
   20|Consider-|Slight      |Good  |Fair  |Fair
     |able     |            |      |      |
   21|Not      |Consider-   |Fair  |Good  |Poor
     |evident  |able; slight|      |      |
     |         |cracking;   |      |      |
     |         |scaling     |      |      |
   22|Medium   |Lateral     |Good  |Good  |Fair
     |         |cracking;   |      |      |
     |         |split       |      |      |
   23|Bad      |Medium deep |Good  |Good  |Fair
   24|Consider-|Slight;     |Fair  |Good  |Good
     |able     |lateral     |      |      |
     |         |cracking    |      |      |
   25|Consider-|Some;       |Fair  |Good  |Excellent
     |able     |lateral     |      |      |
     |         |cracking    |      |      |
  200|Medium   |Bad cracking|Good  |Good  |Fair
  ===+=========+============+======+======+==============

"As before stated, the committee believes that a serious mistake was
made on the test fence in painting out the leads and other formulas on
the various woods without any special attention to reduction to suit the
nature of the wood, thus accounting largely for the difference of the
wearing of the paints on the different woods.

"The reduction of the white leads especially was to be criticised in
these tests, in many cases too much oil and not sufficient turpentine
being present to cause penetration.

"The application of paint to cedar was satisfactory in most all cases,
and this wood showed much better results than the other woods upon the
fences. The exudation of resinous pitch on the hard pine was extremely
serious, in some cases coming through the paint in large streaks,
causing bad results.

"It is to be regretted that the house repainting tests which were
conducted are of no special value, inasmuch as no information is on file
as to the composition of the old paints originally on the houses before
the application of the test paints. Imperfections in the old coating,
such as excessive chalking, deep checking, scaling, rosin exudations,
etc., affected the subsequent coats in such a manner as to prevent any
knowledge of where the new and old paint troubles began. The committee,
therefore, omitted a detailed inspection of such tests.

"Examination of the three houses which were painted over new wood showed
results which correspond with the results obtained from the fence tests.
That is, they showed the ultimate value of high type mixtures of several
pigments over one pigment alone. These tests seem to indicate that very
good results can be secured from most of the paints sold in North
Dakota. If the consumer or householder would exercise more care in the
selection of wood and preparation of surfaces, with due regard to the
proper reduction for various coats, more satisfactory results would be
obtained.

"From an examination of certain paints on the 1908 fence containing
petroleum spirits, it would appear that this paint thinner is of value,
and in the face of conditions such as are presented by the present
scarcity of turpentine, the use of petroleum spirits in moderate
quantity would be justified."

NORTH DAKOTA TESTS

[Illustration: 1. Formula No. 21, Section 31, on 1907 Fence]

[Illustration: 2. Section 80, on 1908 Fence]

[Illustration: 3. Formula No. 6, Section 9, on 1907 Fence]

[Illustration: 4. Formula No. 2, Section 3, on 1907 Fence]

[Illustration: 5. Formula No. 1, Section 1, on 1907 Fence]

[Illustration: 6. Formula No. 14, Section 21, on 1907 Fence]

[Illustration: 7. Formula No. 13, Panel 19, on 1907 Fence]

[Illustration: 8. Formula No. 19, Panel 28. Broad, Deep Checking on
Corroded White Lead on 1907 Fence]

[Illustration: 9. Formula No. 24, Panel 36, on 1907 Fence. Good
Condition. Surface Checking Only]

[Illustration: 10. Formula No. 25, Section 37, on 1907 Fence. Good
Condition. Surface Checking Only]

[Illustration: 11. Formula No. 8, Panel 12, on 1907 Fence]

[Illustration: 12. Formula No. 10, Panel 15, on 1907 Fence]

[Illustration: 13. Panel No. 34, Formula 23, on 1907 Fence. Deep
Checking on Corroded White Lead]

[Illustration: 14. Test No. 13 on 1906 Fence. White Spots Show Paint
Left on Wood. Balance of Paint Split and Disintegrated from Surface]

[Illustration: 15. Test No. 6 on 1906 Fence. Surface Checking Only]

[Illustration: 16. Test No. 2, 1906 Fence. Sublimed White Lead]

[Illustration: 17. Cracks in Test No. 15 on 1906 Fence]

[Illustration: 18. Effect of Cracking on Hard Pine, Causing Splitting of
Painting Coating]

[Illustration: 19. Formula No. 22, Section 23, 1907 Fence. Cracks in
Paint Coating, Caused by Cracks in Wood; Coating Otherwise in Good
Condition]

[Illustration: 20. Test No. 8, on 1906 Fence. Surface Checking Only]

[Illustration: 21. Combination Cracking and Checking on Section 69, on
1908 Fence]

[Illustration: 22. Cracks in Paint Coating, Caused by Cracking of Hard
Pine Wood]

[Illustration: 23. Section 65 on 1908 Fence. Showing Early Breakdown of
Corroded White Lead]



CHAPTER XIII

TENNESSEE PAINT TESTS


=Location and Object of Tests.= On September 15, 1910, the erection of a
wooden test fence was completed on the State Fair Grounds at Nashville,
Tenn. Upon this fence were exposed forty-two samples of white paint, the
object of the test being to determine whether the combination type of
formula is superior to the single pigment type in the southern plateau,
of which Nashville is the centre.

=Construction of Tests.= The construction and outline of these tests
differ somewhat from those conducted at Atlantic City and elsewhere by
the Scientific Section. The fence frame is 150 feet long, being made of
6-inch bevelled girders supported three feet from the ground by 4-inch
posts set six feet apart. Upon this girder were placed a series of
forty-two test panels supported at top and bottom with weather strips
and braces. The test panels used were 40 inches high, 30 inches wide,
and one inch thick, being made of the highest grade white pine, tongued
and grooved together, and protected on the edges by weather strips
projecting from the surface of the panels. Each panel was painted on
both sides with the same paint, thus giving an eastern and western
exposure, the fence running north and south. The formulas used in the
test vary in their percentage composition, being made up in some cases
of single pigments, and again with combinations of the opaque white
pigments, with and without certain percentages of the crystalline or
inert pigments. The paints were applied under the supervision of
prominent master painters and a committee representing the Scientific
Section and other technical organizations.

Other field tests have shown that the sap and knots in hard-grained
woods, such as yellow pine, cypress, etc., have been the cause of the
failure of even the best paints, and that all tests should be conducted
upon soft woods, such as white pine and poplar, if definite results are
to be obtained. Paints tinted with ochre, chrome yellow, lampblack,
iron oxide, etc., have shown on the other field tests which have been
conducted at Atlantic City, Pittsburg, and Fargo the value of these
pigments in giving to the paints increased wearing properties. On the
Southern Test Fence, therefore, all the formulas were ground in white
only and placed upon white pine so as to make the test primarily one to
determine the value of the various white pigments upon good wood.

[Illustration: Tennessee Test Fences]

=Oil and Thinner Tests.= Upon one series of panels on the fence was
placed one of the formulas which had given universal satisfaction on the
various test fences in the past, and this formula was made up with
various oils other than linseed oil, in order to determine the value of
these oils as painting materials. For instance, the vehicle part of the
one formula referred to is made up of 50% linseed oil and 50% soya bean
oil, and again 50% linseed oil and 50% rosin oil, etc., an effort being
made to test out a few of the available semi-drying oils.

The same formula referred to was ground in pure linseed oil and
subjected to a series of tests where it has been thinned for application
as priming and second coats with a series of wood turpentines obtained
from the United States Forest Products Laboratory at Madison, Wis. These
turpentines were made from southern pine stumps and sawdust, and they
vary greatly in their properties. Some were objectionable in odor, while
others were of excellent quality, having an odor almost equal to that of
pure gum spirits.

[Illustration: Views of Fence]

One product under test on the Southern Test Fence is pine oil, a high
boiling point product obtained from the manufacture of wood turpentine
from sawdust. This oil has a boiling point of over 210 degrees
Centigrade as against the 150 degrees of ordinary gum spirits. It is
almost water white and has the same penetrating qualities as the pure
gum spirits; when mixed with 50% linseed oil forming a paint oil of
extremely light color, that produces a semi-flat paint of great
whiteness.

=Reductions and Application.= Formulas No. 1 to No. 37 were all ground
in pure refined linseed oil. They were made in the form of semi-paste
and then thinned down with sufficient refined linseed oil so that each
would have a relative viscosity. To each formula was then added a
sufficient amount of pure lead and manganese linoleate drier to give
proper drying qualities. On thinning for the priming coat, one pint of
turpentine was added to each gallon of paint. For the second coat,
one-half pint turpentine and one-half pint refined linseed oil were
added to each gallon. For the third coat work, reduction was made with
one pint of refined linseed oil.

In the case of formulas 31 to 37, reductions were the same, except that
a series of specially prepared wood turpentines were used in place of
the pure gum spirits used in formulas 1 to 31.

Formulas 38 to 41, as will be shown, were ground in equal parts of the
oils tested. These formulas, however, were all thinned for application
with pure gum spirits of turpentine, and the respective vehicle in which
they were ground.

No inspection of the Tennessee Test Fence has yet been made. The
formulas tested are as follows:

FORMULAS FOR SOUTHERN TEST FENCE

VEHICLE: _Bleached Linseed Oil with Lead and Manganese Linoleate Drier_.

  Formula
  No.

  1 [30]Corroded white lead                100%
  2 [30]Sublimed white lead                100%
  3 Zinc oxide XX                          100%
  4 Zinc lead white                        100%
  5 Leaded zinc 65%, corroded white lead   35%
  6 [30]Corroded white lead                100%
  7 [30]Corroded white lead                100%

  [30] Corroded White Lead is the Basic Carbonate of Lead. Sublimed
       White Lead is the Basic Sulphate of Lead.

No. 8

  Corroded white lead   85%
  Zinc oxide            15%
                       ----
                       100%

No. 9

  Corroded white lead   65%
  Zinc oxide            35%
                       ----
                       100%

No. 10

  Corroded white lead   50%
  Zinc oxide            50%
                       ----
                       100%

No. 11

  Corroded white lead   40%
  Zinc oxide            60%
                       ----
                       100%

No. 12

  Corroded white lead   30%
  Zinc oxide            70%
                       ----
                       100%

No. 13

  Corroded white lead   45%
  Zinc oxide            45%
  Silica                10%
                       ----
                       100%

No. 14

  Corroded white lead   45%
  Zinc oxide            45%
  Asbestine             10%
                       ----
                       100%

No. 15

  Corroded white lead   45%
  Zinc oxide            45%
  China clay            10%
                       ----
                       100%

No. 16

  Corroded white lead   45%
  Zinc oxide            45%
  Barytes               10%
                       ----
                       100%

No. 17

  Corroded white lead   45%
  Zinc oxide            40%
  Silica                15%
                       ----
                       100%

No. 18

  Corroded white lead   45%
  Zinc oxide            40%
  Asbestine             15%
                       ----
                       100%

No. 19

  Corroded white lead   45%
  Zinc oxide            40%
  Barytes               15%
                       ----
                       100%

No. 20

  Sublimed white lead   45%
  Zinc oxide            40%
  Silica                15%
                       ----
                       100%

No. 21

  Sublimed white lead   45%
  Zinc oxide            40%
  Asbestine             15%
                       ----
                       100%

No. 22

  Sublimed white lead   45%
  Zinc oxide            40%
  Barytes               15%
                       ----
                       100%

No. 23

  Zinc oxide            90%
  Calcium carbonate     10%
                       ----
                       100%

No. 24

  Sublimed white lead   40%
  Zinc oxide            45%
  Calcium carbonate     15%
                       ----
                       100%

No. 25

  Corroded white lead   35%
  Zinc oxide            50%
  Silica                15%
                       ----
                       100%

No. 26

  Corroded white lead   20%
  Sublimed white lead   30%
  Zinc oxide            40%
  Asbestine             10%
                       ----
                       100%

No. 27

  Corroded white lead   20%
  Sublimed white lead   20%
  Zinc oxide            40%
  Barytes               10%
  Asbestine             10%
                       ----
                       100%

No. 28

  Corroded white lead   20%
  Sublimed white lead   20%
  Zinc oxide            40%
  Calcium carbonate     10%
  Silica                10%
                       ----
                       100%

No. 29

  Sublimed white lead   20%
  Corroded white lead   20%
  Zinc oxide            30%
  Barytes               10%
  Asbestine             10%
  Calcium carbonate     10%
                       ----
                       100%

No. 30

  Corroded white lead   33%
  Zinc oxide            33%
  Barytes               33%
                       ----
                        99%

No. 31

  Corroded white lead   45%
  Zinc oxide            45%
  Asbestine              5%
  Calcium carbonate      5%
                       ----
                       100%

Formula No.

32. Same as No. 31 but thinned with wood turpentine No. 1.

33. Same as No. 31 but thinned with wood turpentine No. 2.

34. Same as No. 31 but thinned with wood turpentine No. 3.

35. Same as No. 31 but thinned with wood turpentine No. 4.

36. Same as No. 31 but thinned with wood turpentine No. 5.

37. Same as No. 31 but thinned with high-boiling-point petroleum spirits
(turpentine substitute).

38. Same as No. 31 but ground in 50% raw linseed oil, 50% soya bean oil.

39. Same as No. 31 but ground in 50% raw linseed oil, 50% corn oil.

40. Same as No. 31 but ground in 50% raw linseed oil, 50% cotton seed
oil.

41. Same as No. 31 but ground in 50% raw linseed oil, 50% rosin oil.

42. Same as No. 31 but ground in 50% raw linseed oil, 50% pine oil.



CHAPTER XIV

WASHINGTON PAINT TESTS


The new vehicle test fence at Washington is fully described in the
writer's paper[31] as presented before the American Society for Testing
Materials, as follows:

  [31] The Practical Testing of Drying and Semi-Drying Paint Oils, by
       Henry A. Gardner. Paper presented at Fourteenth Annual Meeting,
       Amer. Soc. for Test. Mater., Atlantic City, N.J., June, 1911.

"The high price attained by linseed oil during the past two years of
over a dollar a gallon, together with the unusual scarcity of this
valuable oil, has led many investigators into the field of research,
with a view of discovering some mixture of other oils to partly replace
linseed oil. Many valuable contributions to oil technology have
resulted, but the makers and users of paints have wisely demanded
specific and authoritative information as to the practical value of
proposed mixtures before adopting them. The Institute of Industrial
Research, at the request of the Paint Manufacturers' Association of the
United States, has recently started a series of practical paint vehicle
tests designed to decide the question at issue.

"Forty-eight white-pine panels have been placed upon a test frame on the
grounds of the new laboratory building of the Institute, at Washington,
D. C. They are painted with a standard white pigment formula reduced
with a different oil formula for every panel. White-pine panels were
selected for the test on account of the good painting surface which this
type of lumber presents; the grade selected was free from knots or pitch
pockets--defects which often ruin a paint test. Each panel was
constructed of four tongued-and-grooved planed boards, 22 inches long, 1
inch thick, and 9 inches wide. The boards were leaded together and
capped at the sides with weather strips, making the finished panels
about 2 feet wide and 3 feet high. The fence upon which the panels were
placed was constructed of 4-inch squared yellow pine with open
framework, allowing the panels a resting place upon which they were
finally secured with sherardized screws.

"Before erecting the panels, they were carefully painted in a paint
laboratory especially fitted out for the tests. The work was done during
the months of April and May, the temperature averaging from 60 degrees
to 90 degrees Fahrenheit. This precaution was taken in order that the
paint in each case might become thoroughly dry and hard before exposure,
so that there would be no accumulation of dust or effect from exposure
during the drying period. The actual painting of each panel was done
personally by Mr. Charles Macnichol, master painter, of Washington, D.
C., who has had a wide experience in the practical application and
testing of paints.

[Illustration: View of Panels on Washington Test Fence]

"The viscous nature of several of the oils tested precluded the
possibility of grinding each oil formula with the white pigment base
selected; great heating of the paint mills and a paste of insufficient
fineness was the result of an early attempt at this method. It was
decided, therefore, to grind the standard pigment formula to a thick
paste in the minimum amount of raw linseed oil. Subsequently a weighed
amount of the white pigment base was thinned with the oil formula to be
tested, to a standard viscosity, judged by the experienced master
painter in charge of the practical application of the formulas as
sufficiently heavy for third-coat work. When making the reductions with
oil mixtures, an allowance was made for the amount of linseed oil
already contained in the ground white pigment base.

"During the application of the first coat an equal amount of turpentine
was added to each formula, in the proportion of one-half pint to a
gallon of paint; in the application of the second coat there was added
to each formula a like amount of an equal mixture of turpentine and the
oil formula under test. The third coat was applied without the addition
of thinners of any kind.

"It is well known that the time of drying and the condition of the dried
film of any oil or mixture of drying or semi-drying oils will vary
widely. It is for the purpose of causing oils to set up to a hard film
in a short time that metallic driers in the form of salts of manganese
and lead, soluble in oil, are added to a paint. Some oils require a
large amount of drier, while others require only a very small amount.
Those which require a large amount are apt, upon exposure, to be burned
up by the drier, resulting in the formation of a powdered and
disintegrated film. To add various types of drier or even differing
amounts of a drier to the oils under test, seemed very unfair from every
standpoint, and it was therefore decided to eliminate the drier question
entirely, so as not to vitiate the results by bringing in a factor of
this nature. The plan of omitting driers proved successful in the
Atlantic City steel-panel paint tests, erected three years ago by the
writer under the supervision of Committee A-5 of this Society.

"The systematic methods which are necessary when making paint tests were
carefully followed. A standard weighed amount of white pigment paste was
placed in a clean paint cup and thinned to the proper consistency with a
weighed amount of the oil under test. Proper reductions were made, as
before stated. Weighings of the paint, cup, and brush were made before
and after application to the panel, in order to determine the quantity
of paint used and the spreading power. A period of fifteen days was
allowed between the application of successive coats, in order to give
each formula sufficient time to dry thoroughly. Although several of the
formulas remained tacky for over a week, all dried thoroughly in the
time allotted. (Oils which when used alone have slow drying properties,
have been found to yield good firm films when used with drying pigments
such as lead and zinc.) The backs and edges of each panel were painted
with two coats of the paint used on the face of the panel, so as to
prevent the admission of moisture. After erection, the panels were
numbered with aluminum figures pressed into the surface. Frequent
inspections will be made, and at the proper time reports will be issued
giving the results of the tests.

"During the painting of the panels considerable interesting data were
collected, of which the following is a brief résumé:

"The hiding power of a paint is one of its most important requisites. It
was found in the tests that some oils had the effect of lessening, while
others had the effect of increasing the hiding power of the standard
pigment formula. This may be due in part to the varying refractive
indices of the oils used, as well as to the difference in the quantity
of oil required in each test. Some oils were very viscous, while others
were very light.

"The stiff working of heavy-bodied, blown, or heat-oxidized oils,
produced films which in some cases gave a very glossy surface, even on
the priming coat. Some of these resembled varnished work when finished.
It will be of importance to watch these tests carefully for any signs of
early breakdown, which might come from too thick a film. The treated
Chinese wood oil paints worked rather stiff but produced very smooth
films. The rosin oil paints became slightly lumpy on standing, but
worked out to a smooth finish somewhat yellowish in color. The marine
animal oils, especially the menhaden oil mixtures, dried to a film
slightly flatter than straight linseed oil. Any odor which was present
in the paints made from the animal oils seemed to disappear a few hours
after application. The cotton seed and corn oil mixtures made the
slowest drying paints, but at the end of the second week of the drying
period they set up rapidly to firm films. Soya bean and perilla oils
behaved like straight linseed oil, the former being a little slower and
the latter slightly more rapid in drying properties. The perilla oil was
made from one of the first importations into this country, and was dark
in appearance. It made, however, a very easy-working and hard-drying
paint.

"The oils used in the tests were obtained from reliable sources. After
they were received, they were carefully analyzed. The results of the
analyses appear in Table 1.

TABLE 1. ANALYSES OF OILS USED IN THE VEHICLE TESTS

  ===================================+=========+=========+========+========
                                     |Specific |Saponifi-|Iodine  | Acid
                                     |Gravity  | cation  |Number  |Number
                                     |         | Number  |        |
  -----------------------------------+---------+---------+--------+--------
  Raw linseed oil                    |0.931    |  188    | 186    | 2.0
  Boiled linseed oil (linoleate type)|0.941    |  187    | 172    | 2.7
  Boiled linseed oil (resinate type) |0.930    |  186    | 176    | 2.2
  Blown linseed oil                  |0.968    |  189    | 133    | 2.8
  Lithographic linseed oil           |0.970    |  199    | 102    | 2.7
  Soya bean oil                      |0.924    |  189    | 129    | 2.3
  Menhaden oil                       |0.932    |  187    | 158    | 3.9
  Perilla oil                        |0.94     |  188    | 180    | 2.0
  Chinese wood oil (raw)             |0.944    |  183    | 166    | 3.8
  Chinese wood oil (treated)[32]     |0.898[32]|  128[32]| 104[32]| 6.8[32]
  Corn oil                           |0.925    |  191    | 118    | 9.5
  Cottonseed oil                     |0.921    |  193    | 105    | 3.6
  Rosin oil                          |0.966    |   27    |  41    |16.7
  Whale oil                          |0.924    |  191    | 148    | --
  Neutral petroleum oil[33]          |0.916    |    6    |  12    | --
  ===================================+=========+=========+========+========

  [32] Low constants due to presence of over 40% of volatile matter,
       largely petroleum spirits.

  [33] This oil contained over 20% of petroleum spirits.

"The pigment formula selected for the tests had the following
composition:

  Basic carbonate-white lead    20%
  Sublimed white lead           30%
  Zinc oxide                    35%
  Magnesium silicate            10%
  Barytes                        5%

100 lbs. of pigment base ground to a stiff paste in 16 lbs. of linseed
oil.

"While this pigment formula was not selected as being superior to
certain other formulas, it is of a type that has given very fair service
in paint tests throughout the country, and will no doubt serve admirably
for the purpose designed in these tests.

"The vehicle formulas in the finished paints are as follows:

  No. 1
  Raw linseed oil                 100%

  No. 2[34]
  Soya bean oil                   100%

  [34] Dry pigment formula in soya bean oil.

  No. 3[35]
  Menhaden oil                    100%

  [35] Dry pigment formula in menhaden oil.

  No. 4
  Raw linseed oil                  25%
  Boiled linseed oil (resinate)    75%

  No. 5
  Raw linseed oil                  25%
  Boiled linseed oil (linoleate)   75%

  No. 6
  Raw linseed oil                  50%
  Boiled linseed oil (resinate)    50%

  No. 7
  Raw linseed oil                  50%
  Boiled linseed oil (linoleate)   50%

  No. 8
  Raw linseed oil                  50%
  Blown linseed oil                50%

  No. 9
  Raw linseed oil                  50%
  Litho. linseed oil               50%

  No. 10
  Raw linseed oil                  50%
  Soya bean oil                    50%

  No. 11
  Raw linseed oil                  50%
  Menhaden oil                     50%

  No. 12
  Raw linseed oil                  50%
  Perilla oil                      50%

  No. 13
  Raw linseed oil                  50%
  Treated wood oil                 50%

  No. 14
  Raw linseed oil                  50%
  Corn oil                         50%

  No. 15
  Raw linseed oil                  50%
  Cottonseed oil                   50%

  No. 16
  Raw linseed oil                  50%
  Rosin oil                        50%

  No. 17
  Raw linseed oil                  50%
  Whale oil                        50%

  No. 18
  Raw linseed oil                  75%
  Soya bean oil                    25%

  No. 19
  Raw linseed oil                  75%
  Menhaden oil                     25%

  No. 20
  Raw linseed oil                  75%
  Perilla oil                      25%

  No. 21
  Raw linseed oil                  75%
  Treated wood oil                 25%

  No. 22
  Raw linseed oil                  75%
  Corn oil                         25%

  No. 23
  Raw linseed oil                  75%
  Cottonseed oil                   25%

  No. 24
  Raw linseed oil                  75%
  Rosin oil                        25%

  No. 25
  Raw linseed oil                  50%
  Soya bean oil                    25%
  Menhaden oil                     25%

  No. 26
  Raw linseed oil                  50%
  Soya bean oil                    25%
  Treated wood oil                 25%

  No. 27
  Blown linseed oil                50%
  Soya bean oil                    50%

  No. 28
  Raw linseed oil                  25%
  Soya bean oil                    25%
  Menhaden oil                     25%
  Treated wood oil                 25%

  No. 29
  Raw linseed oil                  25%
  Soya bean oil                    25%
  Menhaden oil                     25%
  Corn oil                         25%

  No. 30
  Raw linseed oil                  25%
  Soya bean oil                    25%
  Menhaden oil                     25%
  Cottonseed oil                   25%

  No. 31
  Raw linseed oil                  25%
  Soya bean oil                    25%
  Menhaden oil                     25%
  Rosin oil                        25%

  No. 32
  Raw linseed oil                  25%
  Soya bean oil                    25%
  Treated wood oil                 25%
  Rosin oil                        25%

  No. 33
  Raw linseed oil                  20%
  Soya bean oil                    20%
  Treated wood oil                 20%
  Menhaden oil                     20%
  Cottonseed oil                   20%

  No. 34
  Raw linseed oil                  20%
  Soya bean oil                    20%
  Treated wood oil                 20%
  Menhaden oil                     20%
  Rosin oil                        20%

  No. 35
  Raw linseed oil                  40%
  Soya bean oil                    20%
  Corn oil                         20%
  Cottonseed oil                   20%

  No. 36
  Whale oil                        33%
  Treated wood oil                 33%
  Raw linseed oil                  33%

  No. 37
  Raw linseed oil                  25%
  L. O.[36]                        75%

  No. 38
  Raw linseed oil                  50%
  Raw Chinese wood oil             50%

  No. 39
  Raw linseed oil                  75%
  Reducing oil[37]                 25%

  No. 40
  Raw linseed oil                  50%
  Soya bean oil                    35%
  Neutral petroleum oil            15%

  No. 41
  Raw linseed oil                  50%
  Soya bean oil                    25%
  Neutral petroleum oil            15%
  Tungate drier                    10%

  No. 42
  Linseed oil                      25%
  Soya bean oil                    37%
  Neutral petroleum oil            23%
  Tungate drier                    15%

  No. 43
  Raw linseed oil                  25%
  Soya bean oil                    37%
  Whale oil                        19%
  Tungate drier                    19%

  [36] Mixture of boiled tung and soya bean oil, thinned with petroleum
       and turpentine.

  [37] 25% raw linseed oil. 73% petroleum oil. 2% drier--lead and
       manganese linoleate."

No. 44

Special test on white base of the following composition, in pure linseed
oil:

  Asbestine                        10%
  Corroded white lead              20%
  Sublimed white lead              30%
  Zinc oxide                       40%

Upper board of panel reduced with straight turpentine on priming coat.
Second board of panel reduced with wood turpentine on priming coat.
Third board of panel reduced with pine oil on priming coat. Bottom board
of panel reduced with petroleum spirits on priming coat.

No. 45

Same pigment formula as No. 44, reduced with:

  Pine oil                         50%
  Linseed oil                      50%

No. 46

Special test of white base of the following composition, in pure linseed
oil:

  Corroded white lead              20%
  Sublimed white lead              30%
  Zinc oxide                       35%
  Asbestine                        15%

No. 47

Cypress panel unpainted.

No. 48

Cypress panel painted with formula No. 1, thinned with benzol on the
priming coat.



CHAPTER XV

CEMENT AND CONCRETE PAINT TESTS


=Damp-proofing and Waterproofing.= The decoration and preservation of
cement and concrete is a subject which is being given the careful
consideration of many technologists on account of the wide usage of
cement for structural purposes, and the necessity of properly guarding
it against the destructive effects of moisture.

To obtain with various paints decorative effects, and, at the same time,
provide a high degree of damp-proofing, is a process quite distinct from
that of water-proofing cement and concrete superstructures. The use, in
small percentage, of stearic acid solutions, aluminum stearate, marine
animal soaps, and other lime-reacting materials, as a component of
concrete while it is being mixed, has been in practice for some time,
the resulting mixture being used largely upon base-work subjected to
water under high pressure. Although some of the materials used for such
purposes actually do give to the concrete a high power of water
resistance, the degree of waterproofing to be obtained through the use
of many such compounds varies to a wide extent, often interfering with
the lime-silica reactions, and ultimately affecting the strength of the
finished concrete.

=Decorative and Preservative Coatings.= The necessity of obtaining
suitable paint coatings for cement and concrete surfaces suggested to
the writer a series of tests on paints designed to prevent the
destructive action of the lime which, by seepage and other physical
action, is brought to the surface, causing saponification of some oil
coatings, as well as destruction of color. The tests referred to were
carried out during 1908, and although great advances have been made
since that time in the preparation of concrete paints, the tests have,
nevertheless, afforded information of a valuable nature as indicating
the proper methods to follow in the painting of cement, as well as
suitable materials to use in the manufacture of cement paints. The
tests, moreover, show the comparative durability of a number of paints
typical of those prominent in the market at the time the tests were
started.

[Illustration: View of Concrete Paint Test Panels]

=Acid Reacting Compounds.= A series of acid reacting washes were
included in the tests, having been designed as prime coaters for use
previous to the application of oil paints. The application of many of
these washes has the effect of neutralizing the lime within cement and
concrete surfaces, and often precipitate insoluble lime compounds which
aid in filling up the outer voids, thus presenting a surface more
suitable to receive oil coatings. To the writer who has since made a
careful study of the painting of concrete, it would seem advisable for
painters to avoid, when possible, the use of these lime neutralizing
washes, as some of them have more or less disintegrating and weakening
influences upon concrete. Recent laboratory experiments, however, have
indicated that zinc sulphate, an acid reacting material used for many
years as a wash for concrete surfaces by Macnichol, actually has a
strengthening effect upon cement and concrete surfaces. The more
successful coatings of to-day, however, are those which may be placed
directly upon the cement and concrete surfaces without the aid of such
washes. Several fairly successful paints of this type have recently
appeared in the market; some of them being made of acid rosins
compounded with vegetable oils. Probably one of the first mixtures of
this sort was the so-called suction varnish which the master painter has
for years used as a prime coating on plastered walls previous to
painting. These suction varnishes generally contain a high percentage of
rosin, a material having an exceptionally high acid value and thus
lending itself successfully to the neutralization of free lime. It has
been claimed, however, by certain practical painters that the lime-rosin
compounds formed when such paints are applied to the exterior of
buildings, are of a brittle nature and subject to early failure. If this
is true, it would seem advisable to use in a concrete paint an oil of a
relatively unsaponifiable nature, which would withstand successfully the
action of the lime, and, at the same time, prevent disruption of the
coating and failure of the color used in the paint.

=Outline of Tests.= The tests referred to as carried out by the writer
were made on a brick wall forty feet long, surface-coated with a
four-inch coating of Portland cement mortar made of one part of Portland
cement and three parts of sharp, clean sand. After the cement had
hardened for three days, the solutions under test were applied.

In many of the tests outlined above, one-coat, as well as two-coat work,
was used on different sections of the test surfaces. It was shown that
the two-coat work gave far better results than with the one-coat work,
and the writer would recommend for the painting of concrete at least
two-coat work. Whenever paints containing Prussian blue or chrome green
are applied to concrete surfaces, immediate whitening in the case of the
blue, and yellowing in the case of the green, will take place, if any
degree of action has been exerted by the lime within the concrete. For
this reason, green is an especially delicate color to test and should be
utilized for this purpose.

The materials used, and the results shown at an inspection made after
two years' exposure, are given herewith.

=Test No. 1.= Concrete primed with a 25% solution of zinc sulphate
crystals dissolved in water. A wide brush was used for the application,
and the spreading rate was approximately 200 square feet per gallon.
Second and third coated on the second day with No. 119 blue paint of the
following composition:

NO. 119 BLUE PAINT

  Sublimed white lead      50%
  Zinc oxide               35%
  Silica and barytes       12%
  Prussian blue             3%

Ground in linseed oil, turpentine and drier.

This panel, after three years' exposure, is in good condition. Slight
checking observed.

=Test No. 2.= Concrete primed with a 20% solution of (alum) (aluminum
sulphate). Second and third coated with No. 119 blue.

In similar condition to Test No. 1.

=Test No. 3.= Concrete primed with zinc sulphate followed by two coats
of para red.

PARA RED FORMULA

  Blanc fixe               60%
  Whiting                  25%
  Zinc oxide                3%
  Paranitraniline lake     12%

Ground in linseed oil, turpentine and drier.

Panel in fair condition with exception of slight crazing. Characteristic
dullness of color after exposure shown. Bright red color restored upon
washing.

=Test No. 4.= Concrete primed with an 8% solution of stearic acid and
rosin dissolved in benzine. Second and third coated with No. 119 blue.

This panel is not in as good condition as Tests Nos. 1 and 2, and would
indicate the inferiority of the priming liquid used. Color failing in
spots and checking observed.

=Test No. 5.= Concrete primed with mixture used in Test No. 4, and then
given two coats of para red.

Test is in about the same condition as No. 4.

=Test No. 6.= Concrete primed with a 10% mixture of acid calcium
phosphate, followed with two coats of No. 119 blue.

The acid phosphate solution evidently had a neutralizing effect upon the
lime in the concrete, as the paint is in fair condition.

=Test No. 7.= Concrete primed with one coat of a soap emulsion of the
following composition, then painted with two coats of No. 119 blue.

  Water                    85%
  Linseed oil              12%
  Alkali                    3%

Very poor results obtained. Destruction of color and peeling resulted.

=Test No. 8.= Concrete primed with one coat of white paint of the
following composition:

PRIMER

  Zinc oxide               25%
  Silica                   35%
  Corroded white lead      20%
  Gypsum                   15%
  Whiting, etc.             5%

Ground in a vehicle of linseed oil and containing 35% of volatile
hydrocarbon spirits and drier.

This coat was followed by one of the following composition, tinted blue:

  Zinc oxide               60%
  Gypsum                   20%
  Silica                   20%

Ground in linseed oil with 12% of turpentine and drier.

Fair results shown during first year, but a breakdown occurred during
the second year, and cracking and scaling resulted.

=Test No. 9.= This test was a duplicate of No. 8 with the addition of 5%
of zinc sulphate solution emulsified into the primer.

Slightly superior to Test No. 8.

=Test No. 10.= Primed with a white paste paint thinned with turpentine.
Second coated with same paint tinted blue.

FORMULA OF PASTE

  Zinc oxide              40%
  Whiting                 30%
  Silica                  20%
  Alumina and gypsum      10%

Ground in 16% of linseed oil vehicle.

Scaling and peeling due to lack of binder and use of saponifiable oil
resulted during the first six months' exposure. Entire destruction of
coating at end of two years.

=Test No. 11.= Primed with a white mixture, and second coated with the
same mixture tinted blue.

FORMULA OF MIXTURE

  Whiting                  30%
  Silica                   30%
  Zinc oxide               40%

Stirred into a 5% solution of glue in water, until a fairly thick paste
was obtained.

Much chalking was shown, and a bleaching of color. It is evident that
this mixture would not serve to keep moisture out.

=Test No. 12 A.= Primed with a 5% solution of soluble nitrated cotton
and paraffin dissolved in equal parts of amyl acetate and benzine.
Second coated with No. 119 blue.

Not very good results were obtained, chalking and slight scaling
resulting.

=Test No. 12 B.= Primed with a heavy varnish containing Chinese wood oil
and kauri gum. Second coated with No. 119 blue.

Fair results obtained.

=Tests Nos. 13, 14, 15, and 16.= Primed with a solution made by
dissolving 10 parts of sodium oxalate in 100 parts of water. Second and
third coated with linseed oil paints in red, brown, blue, and green.

Very good results shown at end of test.

=Test No. 20, Special.= Primed and second coated with a green paint
containing zinc oxide and barytes, ground in an oil having a low
saponification value. Very slow drying was shown. Excellent results. No
failure of color. Extremely glossy, waterproof surface presented.



CHAPTER XVI

STRUCTURAL STEEL PAINT TESTS


=The Necessity of Protective Coatings.= Most painters have in the past
considered of minor importance the painting of iron and steel; any paint
that would properly hide the surface of the metal being accepted without
much question. The demand, however, for structural steel for office
buildings, factories, steel cars, railroad equipment, etc., has doubled
the output of structural paints, and created a demand for painters
having a knowledge of the proper materials to use in the painting of
steel, so that its life may be preserved, and its strength maintained.
Such knowledge is as important to the painter as a knowledge of how to
properly select materials for the painting of wood, and how to temper
these materials to suit the various conditions met with.

=The Cause of Rust.= Everyone is familiar with the appearance of rust,
but few actually understand what causes rust. No attempt will be made
here to present even an outline of the many theories advanced to explain
the phenomenon of the rusting of iron, for the subject is as diverse as
it is interesting. A brief résumé, however, will be given of the now
generally accepted theory that explains the subject. This theory is
called the electrolytic theory. "Auto-electrolysis" is the term used to
define the peculiar tendency of iron to be transformed from a metal
possessing a hard lustrous surface, high tensile strength, and other
useful properties, to a crumbling oxide that falls to the ground and
again becomes part of the earth from which it was originally taken by
man.

[Illustration: A Side View of Steel Test Fences]

This "going back to nature" is more readily accomplished by most of the
steel produced to-day than by the old hand-made irons produced many
years ago. It seems to be a curious fact that the more quickly a product
or an article is fashioned by man, the more quickly it tends to return
again to its original oxidized condition. Some manufacturers of steel,
however, through an understanding of the causes of rust, have progressed
in the manufacture of slow rusting materials, either by the elimination,
or by the proper distribution of impurities.

When iron is brought into contact with moisture, currents of electricity
flow over the surface of the iron between points that are relatively
pure and points that contain impurities. These currents stimulate the
natural tendency of the iron to go into solution, and the solution
proceeds with vigor at the positive points. The air which the water
contains oxidizes the iron which has gone into solution, and
precipitates the familiar brown iron rust. Thus water, which acts as an
acid, and air, which acts as an oxidizer, have combined together to
accomplish the downfall of the metal.

[Illustration: Three Photomicrographs of Corroding Steel]

=Inhibition and Stimulation of Rust.= It is obvious that if means could
be devised to stop the solution pressure of iron and make it resistant
to the flow of surface electric currents, rust could be prevented. Such
methods have been devised, and to better illustrate how they operate, an
analogy may be drawn between iron in water and shellac in alcohol.

It is common knowledge that when shellac is placed in alcohol, the
shellac will force itself into solution in the alcohol, and form a
clear, transparent lacquer. If, however, there should be mixed with the
alcohol a quantity of water, it would be found that the shellac could no
longer go into solution, and it would remain in its original condition.
In the same way, if there be placed in water a small quantity of
material, such as soluble chromates, or an alkaline substance like
caustic soda or lime, it will be found that iron will no longer have a
tendency to go into solution in this treated water, but will stay bright
and clean. These materials which prevent the rusting of iron have been
called by Cushman, who first advanced these explanations, "rust
inhibitors," or materials which inhibit rusting. The paint maker,
realizing the importance of these rust inhibitors, is incorporating them
into paints designed for the protection of iron and steel, and the
success which paints of this type have met with from a practical
standpoint is a justification of what was first called the "electrolytic
theory," which suggested their use.

By placing small, brightly polished steel plates into a mush of paint
pigment and water, a determination may be made of the pigment's effect
upon the metal. Some pigments, under such conditions, cause rapid
corrosion of the steel plates. Such pigments are stimulators of
corrosion, on account of acid impurities which they contain, or because
of their effect in stimulating galvanic currents. Many carbonaceous
pigments are of this type. Other pigments have the effect of keeping
bright the steel plates and preventing rust. Such pigments are of the
inhibitive type, and their action is to check or retard the solution
pressure of the iron.

=The Effects of Moisture.= It might occur to the reader that although
paint pigments, when mixed up with water and brought into contact with
the surface of steel, might show either an inhibitive or stimulative
action, that it is by no means certain that the same tendency will be
exhibited by pigments when they are properly mixed with linseed oil and
laid out as a film upon the surface of steel. In answer to this, it may
be well to state that almost no material used by mankind is absolutely
dry. Linseed oil, as it is pressed from the seed, comes from the cells,
carrying with it a certain small definite percentage of water, and it is
quite certain that even the best linseed oil that goes into use is not
theoretically dry. Everyone knows, of course, that oil and water do not
readily mix and are, in fact, more or less repellent to each other. It
is, however, true that, in spite of this, oils can carry quite a
percentage of water, without the admixture being apparent to the eye. In
addition to this, careful experiments have proved very conclusively that
linseed oil films, even after they have oxidized and hardened, have the
power to a certain extent of absorbing water from the atmosphere. It is,
therefore, safe to say that no linseed oil film in a paint coating is
dry all the time. As a matter of fact, there is abundant evidence to
show that in rainy weather, and, in fact, when the humidity in the air
is high, paint films have absorbed water. As the sun comes out and warms
the paint coating, and the humidity content of the atmosphere falls,
this water to a large extent evaporates out of the film, only to be
taken up again when the weather conditions change. This action may be
likened to a breathing of the paint film, that is to say, an indrawing
of water under humid conditions, followed by an exhaling of water under
dry conditions. With these facts in mind, it must be apparent that
pigments laid out in intimate contact with the surface of steel are
subjected at all times either more or less to the reactions produced by
water contact. Furthermore, as it is a property of water to become
saturated with the gases of the atmosphere, such as oxygen, carbonic and
sulphurous acids, and other impurities, there is present in a protective
paint film at all times the elements necessary to carry on the corrosive
process and reactions.

An outline of Cushman's original research work, upon which has been
based the classification of pigments as inhibitors, stimulators, and
inerts, is clearly presented in his report[38] as Chairman of Committee
U of the American Society for Testing Materials, of which the following
is an excerpt:

  [38] Page 73, 1910 Proceedings of the American Society for Testing
       Materials.

[Illustration: Ferroxyl Tests on Painted Steel Surfaces. Upper Row
Painted with Stimulative Paints--Lower Row with Inhibitive Paints.]

[Illustration: Water Test on Plates Painted--Except in Center Spot. Left
Hand Plates Painted with Stimulative Paints, Right Hand Plates Painted
with Inhibitive Paints.]

[Illustration: View of Steel Plates Painted with Stimulative Paints,
after Immersion in Ferroxyl Jelly.]

"Three years ago the suggestion was made in a paper presented before the
Tenth Annual Meeting of this Society that the various types of
substances used as pigments in protective coatings might exert a
stimulative or an inhibitive action on the rate and tendency to
corrosion of the underlying metal. It was further suggested on a
theoretical ground that slightly soluble chromates should exert a
protective action when employed as pigments by maintaining the surface
of the iron in a passive condition in case water and oxygen penetrated
the paint film. In view also of the well-known fact that alkalies
inhibit while acids stimulate the corrosion of iron, it was suggested
that the action of more or less pure pigments on iron in the presence of
water should be thoroughly investigated. Two years ago this Committee
invited the co-operation of Committee D-1 (then known as Committee E) in
the investigation, and a special sub-committee representing the two main
committees was appointed.

"The methods and results of the water-pigment tests have previously been
reported and published, and need not be given in detail. Briefly, the
method consisted in immersing samples of steel in water suspensions of
the various pigments and blowing air through the containers for definite
periods of time, the corrosion being measured by the loss in weight
sustained by the test pieces. About fifty pigments which are in more or
less common use for painting steel were purchased in the open market and
distributed among a number of the members of the Committee, who agreed
to carry out the work. Each investigator worked independently of the
others, except that the same general method was followed; the time of
exposure to the corroding action, however, varied in the different
experiments. When the results were compared and analyzed by the
sub-committee, it was felt that the general agreement of the results
obtained by the several investigators was striking and merited further
and more systematic work. As a result of these tests the sub-committee
tentatively divided the pigments into inhibitors, stimulators, and
indeterminates. The word 'indeterminate' was selected after considerable
discussion, because the words 'neutral' or 'inert' already possess a
special meaning as applied to paint technology. The Committee takes this
occasion to emphatically state that in adopting this tentative
classification, the words 'inhibitive' and 'stimulative' as used by them
up to the present time apply only to the results obtained in the water
tests, and the inference that the results obtained have decided which
class the pigment will fall into when made into a paint with the usual
vehicles and used as a protective coating on iron and steel, is not
justified. In order to make this point quite clear, it has been agreed
by the Committee to qualify the classification so as to speak of the
various materials tested as 'water stimulative' or 'water inhibitive.'"

[Illustration: Apparatus for Testing the Inhibitive Value of Pigments]

=Importance of Field Tests.= Although the laboratory accelerated tests
for the determination of the relative value of structural steel paints
afford information of some import, there seems to be a general opinion
that the best method to follow, if information of a reliable character
is to be obtained, is to make actual field exposure tests upon large
surfaces. The results of the above described water-pigment tests
suggested the erection of a series of steel panels on which to test out
the same pigments under practical service conditions. The Paint
Manufacturers' Association of the United States erected and painted the
panels, the work being under the constant supervision of the writer, and
the inspection of the work under Committee U of the American Society for
Testing Materials. A brief résumé of the work[39] is herewith presented.

  [39] Page 181, "Corrosion and Preservation of Iron and Steel"--Cushman
       and Gardner--McGraw-Hill Book Co., New York City.

=Pickling and Preparation of Plates.= The three types of metal[40]
selected for the test were rolled to billets, the middle of which were
selected, and worked up into plates 24 inches wide, 36 inches high, and
1/8 inch in diameter--approximately 11 gauge. A number of plates of each
of the metals selected, in all 450, were pickled in 10% sulphuric acid,
kept at 180 to 200 degrees Fahrenheit, in order to remove the
mill-scale. The plates were then washed in water, and later in 10%
solution of caustic soda. Finally the plates were again washed in water
and wiped dry. They were then packed in boxes containing dry lime, in
order to prevent superficial corrosion. By this method the plates were
secured in perfect condition, the surfaces being smooth and free from
scale. Upon these pickled plates paints were applied with a definite
spreading rate of 900 square feet per gallon. The unpickled plates,
coated with mill-scale, were painted with the same paints, but without
adopting any special spreading rate, thus following more closely the
ordinary method of painting structural steel. A few extra plates of
special Bessemer steel and Swedish charcoal iron were also included in
the test, some of which were painted, while others were exposed without
any protective coating. Plates of the three types of metal already
mentioned were also exposed unpainted, both in the black and pickled
condition.

  [40] Bessemer Steel, Open Hearth Steel, and Pure Iron.

[Illustration: Front View of Steel Test Fences]

=Fence Erection and Preparation for Work.= The fences which were erected
for the holding of the plates were constructed of yellow pine, the posts
being set deeply in the ground and properly braced. The framework of the
fence was open, with a ledge upon the lateral girders, upon which the
plates might rest, and to which the plates were secured by the use of
steel buttons. After the framework had been erected, painted, and made
ready for the placement of the panels, a small shed was built upon the
ground, and the materials for the field test placed therein. The steel
plates were unpacked from the boxes in which they were shipped, brushed
off, and stacked up ready for painting. Small benches were erected, and
the accessories of the work, such as cans, brushes, pots, balances,
etc., were placed in position.

=Methods Followed in Painting Plates.= A frame resting upon the
workbench served to hold the plates in a lateral position while being
painted, room being allowed beneath the plate for the operator to place
his hands in order to lift the plates from the under surface after the
painting had been finished.

A pickled plate having been placed upon the framework everything was in
readiness for the work. The specific gravity and weight per gallon of
the paint to be applied was determined, and the amount, in grams, to be
applied to each individual panel was calculated according to the
following formula:

  Spreading rate       Sq. ft. in plate      Grams paint in gal.
   900 sq. ft.     :          6          ::         5400           :  x

The reciprocal of _x_ being the number of grams of paint to be applied
to the panels.

An enamel cup was then filled with the paint and a brush well stirred
within. The cup, paint, and brush were placed upon the balances and
accurately weighed in grams. After most of the paint had been applied to
the panel, cross-brushing of the panel was continued until the pot with
brush and paint exactly counterbalanced the deducted weight. The painted
panel was then set in a rack, in a horizontal position to dry.

A period of eight days elapsed between the drying of each coat. The
greatest care was taken in the painting of the edges of the plates, and
the racks for containing the plates after they were painted were so
constructed that the paint would not be abraded while sliding the plates
back and forth. The working properties of each paint, and the appearance
of the surface of each plate after painting, were carefully noted and
included in the report. No reductions were made to any of the paints
applied except in three cases, where the viscosity was so great that it
was necessary to add a small amount of pure spirits of turpentine. The
amount of paint was proportionately increased in such cases, so that the
evaporation of the turpentine would leave upon the plate the amount of
paint originally intended.

The appearance of the completed series of test panels is shown on page
221.

=Vehicles Used and Reasons for Avoidance of Japan Driers.= The pigments
used were selected with the view to securing as nearly as possible
purity and strength, and as already noted, were out of the same lots
used in making the preliminary laboratory tests on inhibitives. They
were ground in a vehicle composed of two parts of raw linseed oil and
one part of pure boiled oil. Paint is generally caused to dry rapidly by
the use of japan or driers. These materials contain a large amount of
metallic oxides which might have some effect in either exciting or
retarding corrosion. To prevent the introduction of such a factor, these
materials were not used in the test. The boiled oil, with its small
percentages of metallic oxides, was sufficient, however, to cause the
paints to dry in a short time after they were spread.

=Testing Effect of Various Prime Coats.= Some of the special tests made
included a series of plates prime-coated with different inhibitive
pigments, and these tests were designed to determine which pigments
offer the best results for such work. These plates were all
second-coated with the same paint. It is the opinion of the authors that
any good excluding paint may be used whether it be inhibitive in action
or not, provided the contact coat is inhibitive. If, however, both coats
can be designed so as to have the maximum possible value from both these
points of view, the best results would, of course, accrue. The only way
such data can be obtained is by careful observation of the results of
exposure tests.

=Combination Formulas Tested.= By selecting a series of pigments which
in the water tests showed inhibitive tendencies, and properly combining
these pigments into a paint, it was thought possible that a more or less
inhibitive paint would be produced. If this proved to be the case, it
would follow that the selection and introduction into a paint of the
stimulative pigments would inevitably produce a paint unfit for use on
iron or steel.

=Data on Application of Paints.= The recorded data on the application of
the paint to the panels is voluminous. There is presented herewith,
however, the data on two of the paints.

  NO. 2, QUICK PROCESS WHITE LEAD:

  Sp. Gr. of pigment                        6.78
  Lbs. to gallon oil                       20.34
  Sp. Gr. of paint as received              2.47
  Wt. of paint per gallon                  20.56
  Grams to panel                              62
  Condition of paint                        Good
  Working properties                  Works easy
  Drying                       24 hrs. all coats

  1 coat   Oct. 26   T 60   B 29.94   W. fair
  2 coat   Nov.  3   T 54   B 30.23   W. clear
  3 coat   Nov.  7   T 52   B 29.66   W. cloudy

  NO. 9, ORANGE MINERAL (AMERICAN):

  Sp. Gr. of pigment                        8.97
  Lbs. to gallon oil                       26.91
  Sp. Gr. of paint as received              2.97
  Wt. of paint per gallon                  24.74
  Grams to panel                            74.7
  Condition of paint                        Good
  Working properties      Smooth--no brush marks
  Drying                                    Good

  1 coat   Oct. 28   T 58   B 30.01   W. cloudy
  2 coat   Nov.  4   T 65   B 29.61   W. cloudy
  3 coat   Nov.  9   T 58   B 29.91   W. clear

=Composition of Paints.= The following table gives data regarding the
composition, etc., of paints applied to the steel panels.

=Results of Inspection.= The results of an inspection of the steel test
plates, made by Sub-committee D representing Committee D-1 of the
American Society for Testing Materials, is herewith presented:

"On Wednesday, June 28, 1911, the second inspection of the Atlantic City
Steel Test Panels, erected in October, 1908, was made by Sub-committee D
of Committee D-1, this Committee having agreed to report upon the
condition of the painted surfaces, leaving any report on the comparative
corrosion of the various types of metal used in the test to Committee
A-5 on the corrosion of iron.

  ===+=========================+=======+=======+======+=======+=========
     |                         |       |       |      |       |Grams
     |                         |       |       |      |       |Paint
     |                         |       |Wt. of | Sp.  |Wt. of |to Panel
     |           Name          |  Sp.  |Pigment| Gr.  | Paint |at 900
     |                         |  Gr.  |to Gal.| of   |  per  |Sq. ft.
  Pigment                      |of Pig-|of oil |Paint |  Gal. |spreading
  No.|                         | ment  | Lbs.  |Rec'd |  Lbs. |rate
  ---+-------------------------+-------+-------+------+-------+---------
    1|Dutch process white lead | 6.83  | 20.49 | 2.45 | 20.49 |  61.0
    2|Quick process white lead | 6.78  | 20.34 | 2.47 | 20.34 |  62.0
    3|Zinc oxide               | 5.56  | 16.68 | 2.12 | 16.68 |  59.0
    4|Sublimed white lead      | 6.45  | 19.17 | 2.36 | 19.17 |  59.0
    5|Sublimed blue lead       | 6.39  | 19.17 | 2.42 | 19.17 |  61.0
    6|Lithopone                | 4.26  | 12.78 | 1.80 | 12.78 |  45.3
    7|Zinc lead white          | 4.42  | 13.26 | 1.96 | 13.26 |  49.4
    9|American orange mineral  | 8.97  | 26.91 | 2.97 | 26.91 |  74.7
   10|Red lead                 | 8.70  | 26.10 | 2.93 | 26.10 |  73.6
   12|Bright red oxide         | 5.26  | 15.78 | 2.05 | 15.78 |  60.0
   14|Venetian red             | 3.1   |  9.30 | 1.52 |  9.30 |  38.0
   15|Prince's metallic brown  | 3.17  |  9.51 | 1.50 |  9.51 |  37.7
   16|Natural graphite         | 2.60  |  7.80 | 1.37 |  7.80 |  34.4
   17|Acheson graphite         | 2.21  |  6.63 | 1.22 |  6.63 |  30.8
   19| {Lampblack              |       |  1.82}|      |  1.82 |
     | {Barytes                | 1.82  |  8.92}| 1.60 |  8.92 |  40.2
   20|Willow charcoal          | 1.49  |  4.47 | 1.08 |  4.47 |  27.0
   21| {Gas carbon black       | 1.85  |  1.39}| 1.67 |  1.39 |
     | {Natural barytes        |       | 10.03}|      | 10.03 |  50.7
   24|French yellow ochre      | 2.94  |  8.82 | 1.46 |  8.82 |  37.0
   27|Natural barytes          | 4.46  | 13.38 | 1.83 | 13.38 |  46.0
   28|Precipitated barytes     | 4.23  | 12.69 | 1.84 | 12.69 |  46.0
     |(blanc fixe)             |       |       |      |       |
   29|Calcium carbonate        | 5.48  |  8.22 | 1.37 |  8.22 |  34.5
     |(whiting)                |       |       |      |       |
   30|Calcium carbonate        | 2.56  |  7.68 | 1.35 |  7.68 |  34.0
     |precipitated             |       |       |      |       |
   31|Calcium sulphate (gypsum)| 2.33  |  6.99 | 1.25 |  6.99 |  31.4
   32|China clay (kaolin)      | 2.67  |  8.01 | 1.34 |  8.01 |  34.0
   33|Asbestine (silicate of   | 2.75  |  8.25 | 1.38 |  8.25 |  34.7
     |magnesium)               |       |       |      |       |
   34|American vermilion       | 6.83  | 20.49 |      | 20.49 |  64.5
     |(chrome scarlet)         |       |       |      |       |
   36|Medium chrome yellow     | 5.88  | 17.64 |      | 17.64 |  67.1
   39|Zinc chromate            | 3.57  | 10.71 | 1.57 | 10.71 |  39.2
   40|Zinc and barium chromate | 3.45  | 10.35 | 1.58 | 10.35 |  40.0
   41|Chrome green (blue tone) | 4.44  | 13.32 | 1.94 | 13.32 |  49.0
   44|Prussian blue            | 1.96  |  5.88 |      |  5.88 |  30.0
   45|Prussian blue            | 1.93  |  5.79 |      |  5.79 |  34.5
   48|Ultramarine blue         | 2.40  |  7.20 | 1.29 |  7.20 |  32.5
   49|Zinc and lead chromate   | 4.76  | 14.28 | 1.92 | 14.28 |  48.3
   51|Magnetic black oxide     |       | 15.00 | 1.92 | 15    |  48.3
     |                         |       |       |      |       |
     |   _Composite Paints_    |       |       |      |       |
     |                         |       |       |      |       |
  111|Brown } Made from pig-   |       | 10.82 | 1.30 | 10.82 |  32.7
  222|Black } ments that were  |       | 10.86 | 1.30 | 10.86 |  32.8
  333|White } inhibitive in the|       | 14.52 | 1.74 | 14.52 |  43.8
  444|Green } water test       |       | 12.77 | 1.53 | 12.77 |  38.6
     |                         |       |       |      |       |
  555|Black } Made from pig-   |       |  9.37 | 1.125|  9.37 |  28.
  666|Brown } ments that were  |       | 11.74 | 1.41 | 11.74 |  35.5
  777|White } stimulative in   |       | 14.55 | 1.75 | 14.55 |  44.
  888|Green } the water test   |       | 14.57 | 1.75 | 14.57 |  14.57
  ===+=========================+=======+=======+======+=======+=========

"According to the amount of rust apparent on the painted surfaces of the
panels, as well as the degree of checking, chalking, scaling, cracking,
peeling, loss of color, and other signs of paint failure shown, ratings
were given each panel. The system of rating which took into
consideration all the above conditions, was similar to the system used
at the first inspection during 1910, when 0 (zero) recorded the worst
results and 10 (ten) the best results.

"In Table No. 1 there is shown the rating accorded by each inspector to
each panel, as well as an average for each panel.

TABLE NO. 1.--SECOND INSPECTION OF STEEL PAINT TEST PANELS AT ATLANTIC
CITY, N. J., BY SUB-COMMITTEE D OF COMMITTEE D-1

  =======+========================+======+======+=======+=======+=======
         |                        |      |      | H. A. |       |
   Panel |                        |W. H. |P. H. |Gardner|  C.   |
    No.  |         Pigment        |Walker|Walker|Chair- |Chapman|Average
         |                        |      |      |  man  |       |
  -------+------------------------+------+------+-------+-------+-------
       1 |Dutch process white lead| 2    | 3    |  3    |  5    |  3.7
       2 |Quick process white lead| 4    | 4    |  3    |  6    |  4.2
       3 |Zinc oxide (XX)         | 1    | 1-1/2|  1    |  2-1/2|  1.5
       4 |Sublimed white lead     | 9    | 9-1/2|  9    |  8-1/2|  9.0
       5 |Sublimed blue lead      | 9    | 9-1/2|  9-1/2|  7-1/2|  8.8
       6 |Lithopone               | 2    | 1-1/2|  2    |  3-1/2|  2.2
       7 |Zinc lead white         | 3    | 4    |  5    |  7    |  4.7
       9 |Orange mineral          | 9    | 9    |  9    |  6-1/2|  8.3
      10 |Red lead                | 9    | 9    |  9    |  6-1/2|  8.3
      12 |Bright red oxide        | 8-1/2| 9    |  8    |  7    |  8.1
      14 |Venetian red            | 7    | 9    |  7    |  9    |  8.0
      15 |Prince's metallic brown | 5    | 7-1/2|  6    |  8    |  6.3
      16 |Natural graphite        | 6    | 8    |  4    |  9-1/2|  6.8
      17 |Artificial graphite     | 5    | 7-1/2|  4    |  7    |  5.9
      19 |Lampblack               | 5    | 7-1/2|  5    |  8    |  6.3
      20 |Willow charcoal         | 9    | 8-1/2|  9    |  9    |  8.8
      21 |Carbon black            | 7    | 8-1/2|  5    |  8-1/2|  7.2
      24 |Yellow ochre (French)   | 5    | 7    |  2    |  8    |  5.5
      27 |Barytes (natural)       | 1    | 1    |  1    |  0    |  0.7
      28 |Barytes (precipitated)  | 2    | 1-1/2|  2    |  2    |  1.8
      29 |Calcium carbonate       | 0    | 0    |  0    |  0    |  0.0
         |(whiting)               |      |      |       |       |
      30 |Calcium carbonate (pre- | 0    | 0    |  0    |  0    |  0.0
         |cipitated)              |      |      |       |       |
      31 |Calcium sulphate        | 1    | 1    |  1    |  3    |  1.7
         |(gypsum)                |      |      |       |       |
      32 |China clay (kaolin)     | 6    | 6    |  7    |  6-1/2|  6.3
      33 |Asbestine (magnes. sili-| 5    | 4-1/2|  6    |  5    |  5.1
         |cate)                   |      |      |       |       |
      34 |American vermilion      |10    |10    | 10    | 10    | 10.0
      36 |Lead chromate           | 7    | 7-1/2|  8-1/2|  8    |  7.7
      39 |Zinc chromate           | 9    | 9    | 10    |  9-1/2|  9.5
      40 |Zinc and barium chromate| 9    | 9-1/2| 10    |  9-1/2|  9.5
      41 |Chrome green (blue tone)|10    |10    | 10    |  9-1/2|  9.8
      44 |Prussian blue, W. S     | 9    | 9-1/2|  9-1/2|  9    |  9.0
      45 |Prussian blue, W. I     | 8    | 9-1/2|  8-1/2|  8-1/2|  8.5
      48 |Ultramarine blue        | 0    | 0    |  0    |  0    |  0.0
      49 |Zinc and lead chromate  |10    | 9-1/2| 10    |  9-1/2|  9.7
      51 |Magnetic black oxide    | 9    | 9-1/2| 10    |  9-1/2|  9.5
     111 |Brown composite paint   | 7    | 9    |  9    |  9    |  8.5
     222 |Black composite paint   | 9    | 9    |  9    |  8-1/2|  8.8
    3333 |White composite paint   | 4    | 4    |  7    |  3    |  4.5
     444 |Green composite paint   | 5    | 7    |  7    |  8    |  6.7
     555 |Black composite paint   | 9    | 9    |  6    |  9    |  8.2
     666 |Brown composite paint   | 8    | 8    |  6    |  9    |  7.7
     777 |White composite paint   | 7    |10    |  5    |  7    |  7.2
     888 |Green composite paint   | 7    | 8    |  8    |  9    |  8.0
    2000 |1 coat zinc chromate   }| 8    | 8-1/2|  8    |  8    |  8.1
         |1 coat iron oxide ex-  }|      |      |       |       |
         |cluder                 }|      |      |       |       |
    3000 |1 coat lead chromate    | 7    | 8    |  7    |  7-1/2|  7.3
    4000 |1 coat red lead        }| 7    | 8-1/2|  8    |  7-1/2|  7.7
         |1 coat iron oxide ex-  }|      |      |       |       |
         |cluder                 }|      |      |       |       |
     100 |Straight carbon black   | 5    | 8-1/2|  4    |  8-1/2|  6.5
         |paint with turps and    |      |      |       |       |
         |drier                   |      |      |       |       |
      90 |Straight lampblack paint| 5    | 7    |  3    |  8    |  5.7
         |with turps and drier    |      |      |       |       |
    5555 |Coal tar paint over red | 4    | 8    |  2    |  7    |  5.2
         |lead                    |      |      |       |       |
    1000 |Chrome resinate in oil  | 1    | 0    |  0    |  2    |  0.7
         |(1 coat)                |      |      |       |       |
  1 plate|3 coats boiled linseed  | 1    | 0    |  1    |  4    |  1.5
         |oil                     |      |      |       |       |
  =======+========================+======+======+=======+=======+=======

"In Table No. 2 there is shown the rating obtained by those panels which
were considered by the committee as meriting from 8 to 10, and having
given the best all-round service.

TABLE NO. 2.--ANALYSIS OF AVERAGES. GRADE OF EXCELLENCE FROM 8 TO 10

  =====+=============================================+=======
  Plate| Pigment                                     |Average
  -----+---------------------------------------------+-------
    34 | American vermilion (basic chromate of lead) |  10.0
    41 | Chrome green                                |   9.8
    49 | Lead and zinc chromate                      |   9.7
    39 | Zinc chromate                               |   9.5
    40 | Zinc and barium chromate                    |   9.5
    51 | Black oxide of iron                         |   9.5
     4 | Sublimed white lead                         |   9.0
    44 | Prussian blue                               |   9.0
     5 | Sublimed blue lead                          |   8.8
    20 | Willow charcoal                             |   8.8
   222 | Composite paint                             |   8.8
    45 |  Prussian blue                              |   8.5
   111 | Composite formula                           |   8.5
     9 | Orange mineral                              |   8.3
    10 | Red lead                                    |   8.3
   555 | Composite paint                             |   8.2
    12 | Bright red oxide of iron                    |   8.1
  2000 | 1 coat zinc chromate; 1 coat iron oxide     |   8.1
    14 | Venetian red                                |   8.0
   888 | Composite paint                             |   8.0
  =====+=============================================+=======

=Comparison of Results.= It is of interest to compare with Table 2 of
the above report, Table 2 of the 1910 report of Committee U of the
American Society for Testing Materials. Both charts show the highly
inhibitive pigments to be in the lead.


COMMITTEE U REPORT 1910

TABLE II.--ANALYSIS OF AVERAGES. GRADE OF EXCELLENCE FROM 8 TO 10

(_Only resistance to corrosion was considered, and only pigments which
were common to both tests are included_)

  ===+====================================+=======
  No.| Pigment                            |Average
  ---+------------------------------------+-------
  34 | American vermilion (chrome scarlet)|  9.8
  41 | Chrome green (blue tone)           |  9.7
  40 | Zinc and barium chromate           |  9.7
   5 | Sublimed blue lead                 |  9.6
   4 | Sublimed white lead                |  9.5
  49 | Zinc and lead chromate             |  9.5
  39 | Zinc chromate                      |  9.4
  12 | Bright red oxide                   |  9.3
  44 | Prussian blue (water stimulative)  |  9.2
  16 | Natural graphite                   |  9.1
   9 | Orange mineral (American)          |  9.0
  36 | Medium chrome yellow               |  9.0
   2 | White lead (quick process)         |  8.9
  20 | Willow charcoal                    |  8.8
  45 | Prussian blue (water inhibitive)   |  8.8
   1 | White lead (Dutch process)         |  8.7
  10 | Red lead                           |  8.7
  7  | Zinc lead white                    |  8.0
  ===+====================================+=======

The writer has recently made a careful inspection of the panels painted
with single pigment paints, and has made the following brief summary of
the characteristic appearance of each.

=Panel No. 1--Dutch Process White Lead.= The excessive chalking which
took place began to disappear at the end of a year, being washed away by
the rains and carried away by the winds, so that there was left upon the
surface but a thin coating of pigment, insufficient to give good
protection. Slight corrosion was apparent beneath the film.

=Panel No. 2--Quick Process White Lead.= In the same condition as Panel
No. 1.

=Panel No. 3--Zinc Oxide.= Panel covered with thin lateral streaks of
rust, due to the admittance of moisture in cracks caused by brittleness
of film. Result doubtless due to insufficient amount of oil used with
pigment. Removal of film shows steel very bright except where cracks
have formed.

=Panel No. 4--Sublimed White Lead.= Although sublimed white lead chalked
very heavily, the chalked pigment seemed to be tenacious and adhered to
the plate, presenting an excellent surface with absence of rust. Film of
good color and quite elastic.

=Panel No. 5--Sublimed Blue Lead.= In same condition as Panel No. 4, but
color has slightly faded.

=Panel No. 6--Lithopones.= Lithopone was early destroyed, as is usual
with this pigment when used alone on exterior surfaces. It became rough
and discolored, presenting a very blotchy appearance and disclosed the
formation of rust working through the film.

=Panel No. 7--Zinc Lead White.= In general good condition with the
exception of the color, which is slightly dark. Medium chalking was
apparent but only very slight corrosion appeared.

=Panel No. 9--Orange Mineral.= In excellent condition, showing a good
firm surface with no checking or corrosion apparent. Shortly after
exposure the film became covered with a white coating of carbonate of
lead, which indicates action of the red lead with the carbonic acid of
the atmosphere. Removal of this white coating with water discloses the
brilliant color of the unaffected portion of the red lead.

=Panel No. 10--Red Lead.= In same condition as Panel No. 9.

=Panel No. 12--Bright Red Iron Oxide.= In general good condition. Film
intact and unfading in color.

=Panel No. 14--Venetian Red.= Similar to Panel No. 12, but slight
corrosion apparent beneath, in localized spots, and film showing slight
wart-like formations.

=Panel No. 15--Prince's Metallic Brown.= Similar to Panel No. 14.

=Panel No. 16--Natural Graphite.= Deeply pitted in spots, showing
bulbous eruptions, indicating the stimulative nature of this pigment.

=Panel No. 17--Artificial Graphite.= In same condition as Panel No. 16.

=Panel No. 19--Lampblack and Barytes.= Although the film seems to be
intact, there are apparent abrasions of the surface showing stimulative
corrosion effects of a pronounced nature.

=Panel No. 21--Carbon Black and Barytes.= In same condition as Panel No.
19.

[Illustration: Corrosion Pits on Graphite Panel]

[Illustration: Rust on Stripped Graphite Film]

[Illustration: Section of Wire Painted with a Stimulative Carbonaceous
Paint]

[Illustration: Corroded and Pitted Surface of Plate Painted with
Stimulative Paint]

The longevity of lampblack and carbon black paint films when applied to
wood has been attributed to the slow drying nature of these pigments
when mixed with oil. It is assumed that they have the property of
keeping the oil in a semi-drying condition, which will not disintegrate
as early as when the oil is thoroughly dried to linoxyn. If this is
true, it would seem advisable to use with hard-drying pigments, a
proportion of some oil that is semi-drying in nature or one which will
leave a film not too hard. Soya bean oil, wood oil, and fish oil present
themselves as candidates for such use. How they will work in practice,
however, is a question not yet determined. On the other hand, it is well
known that these pigments require enormous quantities of oil in order to
grind to a working consistency, and it is possible that the life of
such coatings is due rather to the property of these pigments, of taking
up large quantities of oil, than to their effect upon the slow drying of
oil. Excessive oil carrying, however, should be avoided, as shown by the
early failure and pitting of those carbon black and lampblack paints
ground with very large quantities of oil, as is the usual practice. When
these carbon and lampblack pigments were ground with barytes (which is a
heavy pigment and requires only about 9 pounds of oil to 100 pounds of
pigment, as against 175 pounds of oil to 100 pounds of lampblack), it
was found that the lampblack and carbon black paints were reinforced and
made more suitable for actual practice. The stimulative nature of these
black pigments, however, asserted itself in both cases, and large
pittings and eruptions were evident at the end of a year. Carbon black,
lampblack, graphite, or any other good conductor of electricity should
never be placed next to the surface of iron. They are good as
top-coatings, but not as prime-coaters. Some pigments are stimulators of
corrosion, because they contain water-soluble impurities that hasten the
rusting, while others, like graphite, hasten it simply because, being
good conductors, they stimulate surface electrolysis.

=Panel No. 20--Willow Charcoal.= In excellent condition throughout.
Presence of small quantities of potash may be responsible for the
inhibitive nature of this black pigment.

=Panel No. 24--Ochre.= While the film seems intact, it has a very
mottled appearance and examination shows eruptions of rust through the
film, in several places.

=Panel No. 27--Natural Barytes.= Within a year the film became
pin-holed, and corrosion was apparent. At the end of three years very
little of the pigment was left upon the plate, having chalked and scaled
off. Barytes has proved its usefulness as a constituent of a combination
type of paint, but it should not be used alone.

=Panel No. 28--Blanc Fixe.= In the same condition as Panel No. 27, but
slightly more chalking and disintegration was shown.

[Illustration: Panel Painted with Blanc Fixe. Right Side Stripped of
Paint to Show Corrosion]

[Illustration: Scaled Whiting Films

Chemically Active Pigments and Their Effect After Eighteen Months'
Wear]

[Illustration: Plate Showing Effect of Chemically Active Pigments on Oil
after One Year's Wear]

=Panel No. 29--Whiting.= Plates coated with calcium carbonate or whiting
in oil presented a very fair appearance at the start of the test, but
they soon began to chalk and disintegrate. It is well known that
whiting, being alkaline, has the property of acting on oil and causing
its early disintegration by saponification. As a matter of fact, six
months after the whiting plates were exposed, crumbling of the surface
appeared, and twelve months was sufficient for the total destruction of
the paint. At this time the rusted surface of the plates which had been
painted with calcium carbonate, seemed not to rust as fast as those
plates which were exposed without paint coatings, and the rust which had
formed appeared to be of an even, fine texture. On the lower left-hand
corner of these plates had been lettered the figures "29" and "30,"
using lampblack in oil. One of the most remarkable things which appears
on the fence to-day is the perfect condition of these lampblack letters
over their priming coat of calcium carbonate, standing out in clear
relief against the rusted metal. This test would suggest, therefore,
that if the surface of metal is properly protected with a pigment which
is slightly alkaline or inhibitive in nature, and then topped with a
good weather-resisting material, such as lampblack, graphite or carbon
black, good results would be obtained. Further tests will be made to
determine the value of this suggestion.

=Panel No. 30--Precipitated Calcium Carbonate.= Showed more rapid
destruction than Panel No. 29.

[Illustration: Corrosion Adhering to Film Stripped from Panel Painted
with Gypsum (Calcium Sulphate)]

=Panel No. 31--Calcium Sulphate.= Under the paint film of gypsum, rust
soon appeared, showing that the film was not a good excluder of
moisture. Although the film remained intact, rusting progressed
throughout the test and considerably darkened the color of the paint.

=Panel No. 32--China Clay.= This pigment gave excellent service for
eighteen months. Afterwards indications of corrosion were shown, and
apparent breakdown of the film was indicated.

[Illustration: China Clay

Asbestine

Gypsum]

=Panel No. 33--Asbestine.= In the same condition as Panel No. 32.

[Illustration: Excellent Surface shown by American Vermilion after
nearly Four Years' Exposure]

=Panel No. 34--American Vermilion.= This pigment has given perfect
protection to the plates. The film is strong and elastic, and upon
removal reveals the bright steel. No chalking, checking, discoloration,
or other signs of paint failure are shown. It would appear that the
inhibitive characteristics of this pigment are pronounced, and it
promises to give efficient service for several years more.

=Panel No. 36--Lead Chromate.= This panel is in generally fair
condition, but slight checking is shown.

[Illustration: Perfect Condition of Plate Painted with Zinc Chromate;
One Half Stripped. (_Negative cracked_)]

=Panel No. 39--Zinc Chromate.= This panel is in condition similar to
Panel No. 34, presenting a perfect appearance, with decided maintenance
of color, elasticity of film, and freedom from any bad characteristics.
It has proved to be one of the highest type rust inhibitive pigments.

=Panel No. 40--Zinc-and-Barium-Chromate.= Although the color of this
pigment is not very pleasing, it has proved itself to be the equal of
zinc chromate in its protective value.

=Panel No. 41--Chrome Green.= In excellent condition. Presents an
appearance similar to Panels Nos. 34 and 39. Its surface is perfect and
will doubtless give service for many years.

=Panel No. 44--Prussian Blue.= This panel stands forth as the most
wonderful moisture-excluder in the whole test, its surface presenting an
appearance similar to a varnished plate, even after three years'
exposure. Action between the pigment and the oil, resulting in the
formation of iron linoleate, may account for this property.

=Panel No. 45--Prussian Blue.= In same condition as Panel No. 44.

=Panel No. 48--Ultramarine Blue.= Soon after this test was exposed,
early vehicle decay and excessive chalking were observed. The admittance
of moisture may have caused the formation of acid with the sulphur
content of the pigment, which would account for the rapid corrosion
which followed. It is of a pronounced stimulative type. The effect of
stimulative under-coatings is well shown on some special plates on the
fence, which when received were not pickled before painting, but had
upon their surfaces the ordinary coating of mill scale. Over this had
been stencilled in a triangular form the trade mark of the manufacturer.
The stencilling material was made of ultramarine blue. When these plates
were painted with some of the special paints, and exposed, the
stimulative nature of the ultramarine blue began to assert itself, and
within a short time, wherever the stencil marks were located, signs of
rust began to appear through the coatings of top paint which had been
applied. Corrosion under these stencil marks became so great that the
trade mark was plainly outlined in letters of rust. This would seem to
be final proof that pigments of a stimulative nature should never be
used for the priming of iron and steel.

=Panel No. 49--Zinc-Lead Chromate.= In excellent condition throughout,
with a smooth surface and showing no corrosion. Stands in the same class
as Panels Nos. 34 and 39.

[Illustration: Effect of Stimulative Paint. Manufacturer's Trade Mark
Stencilled on Bare Metal in Triangular Form, showing Through Subsequent
Paint Coating]

=Panel No. 51--Black Magnetic Oxide of Iron.= In excellent condition.



CHAPTER XVII

THE SANITARY VALUE OF WALL PAINTS


=Decoration and Sanitation.= The proper decoration of the interior of
dwellings and public buildings has become of even greater importance
than the protection and decoration of exteriors. There is, moreover, an
increasing demand for harmonious effects and the production of more
sanitary conditions than have prevailed in the past. Up until a few
years ago a great variety of wall papers of more or less pleasing
appearance were almost exclusively used for the decoration of walls in
the interior of buildings, and their application was commonly considered
the most effective means of wall decoration. There seems to be no
question, however, that the use of wall paper is steadily decreasing,
and that the art of interior decoration is undergoing a transition to
the almost universal use of paint.

Modern progress demands the maintenance of sanitary conditions for the
benefit of the public welfare, and there is no doubt that from the
standpoint of sanitation and hygiene, properly painted wall surfaces are
far superior to papered walls. There is an abundance of evidence which
shows that dust germs may easily be harbored, and thus disease
transmitted from wall paper. In the tenement houses, which are common to
the larger cities, and to a lesser extent in the dwellings found in
smaller communities, where tenants are more or less transient, the
continued maintenance of sanitary conditions presents a difficult
problem. Infectious and epidemic illnesses generally leave behind
bacilli of different types, which may find a culture medium in the
fibrous and porous surfaces presented by wall paper, backed up as they
invariably must be by starch, casein, or other organic pastes.
Occasionally the restrictions of local boards of health provide in such
events for proper fumigation, but too often no precautions are taken to
destroy the disease germs which are caught in the dust which collects on
wall paper. As a rule, both tenant and landlord are oblivious to all
conditions which cannot be readily seen or detected. Burning sulphur,
one of the most effective means of fumigation, will generally cause
bleaching and consequent fading of the delicate colors used in printing
the designs upon wall paper. Washing of the paper with antiseptic
solutions will destroy its adhesiveness to the plaster and often cause
bulging and general destruction.

[Illustration: Heavy Colonies of Bacteria Developing in Agar Jelly
Treated with Washings from Wall Paper

Practically no Development of Bacterial Colonies in Agar Jelly Treated
with Washings from Sanitary Wall Paint]

=Hospital Practice.= In hospitals, where it is necessary to maintain
sanitary conditions, the walls are invariably painted, and requirements
should demand the use of paints which can be washed frequently, so that
there will be no possibility of uncleanliness. Inquiry made of a
prominent surgeon[41] connected with one of the large metropolitan
hospitals substantiated the writer's findings regarding the greater
sanitary value of wall paints, and brought forth the information that in
hospitals under construction provision had been made for the finishing
of walls so that a hard, non-absorbent, and washable surface might be
obtained. The same authority stated that the common practice, in
apartments and tenements, of covering the old wall paper over with a
layer of new each time a tenant moved in, should be condemned, and that
from a hygienic standpoint the use of sanitary wall paints should be
advocated in all dwellings as well as public buildings.

  [41] Dr. F. F. Gwyer, Cornell Uni. Med. Col., New York City.

If such conditions are maintained in hospitals, where special attention
is paid to sanitation, it would appear that similar precautions should
be equally as necessary in public buildings and in dwellings--wherever,
in fact, people congregate or live.

=Sanitary Wall Paints.= There have recently appeared in trade a number
of wall paints composed of non-poisonous pigments ground in paint
vehicles having valuable waterproofing and binding properties, and of a
nature to produce the flat or semi-flat finish that has become so
popular. Such paints produce a sanitary, waterproof surface, which
permits of frequent washing. By their use it is possible to secure a
more permanent and a wider range of tints than can be obtained with wall
paper, as they are produced in a myriad of shades, tints and solid
colors, from which any desired combination may be selected. On the
border or on the body of walls decorated with such paints, attractive
stencil designs, which bring out in relief the color combinations, may
be applied.

For the decoration of chambers and living rooms, delicate French grays,
light buffs, cream tints and ivory whites may be used, while in the
library and other rooms richer and more solid colors, such as greens,
reds, and blues, may be harmoniously combined.

=Defects of Wall Paper.= It recently occurred to the writer to
investigate the conditions which obtain in many apartment houses in the
larger cities. Inspection of a number of such places, in which wall
paper had been exclusively used on the walls, showed generally bad
conditions; bulging of the surfaces, caused by dampness in the walls,
which had loosened up the binder, as well as peeling and dropping of the
paper from the ceilings, were frequently observed. In many cases a
shabby appearance was shown, accompanied by an odor which suggested
decomposition of the paste binder used on the paper. The writer was
impressed with the fact that such conditions could easily be avoided by
the very simple expedient of using properly manufactured wall paints,
which are so easily made dustproof and waterproof.

Samples of wall paper, which had been applied to plastered walls for a
year or more, were obtained, and examination under the microscope showed
a most uncleanly surface. Cultures were made of these samples, and
bacilli of different types were developed in the culture medium in a
short time.

=Experimental Evidence.= That the above conditions could not have
existed, had proper wall paints been used, seemed doubtless, and
suggested a carefully conducted experiment to prove the relative
sanitary values of wall paper and wall paints. A large sheet of fibre
board, such as is occasionally used to replace plastered walls, was
painted on one side with a high-grade wall paint, three-coat work. A
similar sheet was papered on one side with a clean, new wall paper.
These test panels were placed where unsanitary conditions, such as
dampness, foul odors, and a scarcity of air were present. After a short
period of exposure, the panels were taken to the bacteriological
laboratory and a small section of the painted surface, about two inches
square, as well as a small section of the papered surface of similar
size, were removed and used for making cultures. In each case the
surface of the section under test was washed with 100 c.c. of distilled,
sterilized water. The washings which dripped from the surface were
collected in a graduated flask. One c.c. of the washings was used in
each case, admixed with bouillon and again with agar-agar. The enormous
development of bacteria in the bouillon, treated with the washings from
the wall-papered surface, was sufficient evidence to convince one of the
greater sanitary value of the wall paint, the washings from which gave a
culture practically free from bacteria. The colonies of bacteria shown
in the petri-dish test made of the washings from wall paper further
supports these findings. It will be noticed that the tests made from the
washings of the wall paint show practical absence of bacteria, and was
clear, as was the bouillon-solution test of the paint. The washings from
the wall paper showed active development of bacteria, both in the
bouillon and agar tests.

[Illustration: DEVELOPMENT OF BACTERIA IN BOUILLON SOLUTIONS

Note Practical Freedom of Bacteria in Clear Bouillon Solution Treated
with Washings from Sanitary Wall Paint

Note Milky Appearance of Solution Due to Heavy Development of Bacteria
in Bouillon Treated with Washings from Wall Paper]

_From the Conservation Standpoint_: It would be of interest to sum up in
figures the acreage and cordage of wood that annually is transformed
into pulp for the manufacture of wall paper. Unfortunately, there are no
available statistics on this subject. It is clear, however, that from
the standpoint of conservation the use of wall paints should take
precedence over the use of wall paper.



INDEX


                                                               PAGE

  Abrasion, apparatus for determining resistance to,            153
  Acid reacting compounds,                                      215
  Actinic light tests,                                          112
  Adhesive power of Paint Coating,                              104
  Aluminum Silicate,                                             62
  American Vermilion,                                            64
  Analogies of Paint and Concrete manufacture,                   94
  Analyses of Averages in Atlantic City steel paint test,  235, 236
    Corn Oil,                                                    16
    Cottonseed Oil,                                              15
    Debloomed Mineral Paint Oil,                                 18
    Iron Oxide Pigments, table,                                  63
    Linseed Oil,                                                  7
    Menhaden Oil,                                                14
    Oils used in Washington tests,                              211
    Petroleum Spirits,                                           20
    Rosin Oil,                                                   16
    Soya Bean Oil,                                                8
    Sunflower Oil,                                               15
    Tung Oil,                                                    12
    Whale Oil,                                                   14
    Wood Turpentine,                                             19
  Asbestine,                                                     55
  Atlantic City fence tests,                                    107
    steel paint tests,                                      228-235
    Checking,                                                   122
    Gloss,                                                      122
    Hiding power,                                               122
    inspection of,                                              114
    Methods used,                                               114
    Results,                                                    124
  Auto-electrolysis,                                            220

  Bacteria in wall paper,                                       256
  Barium Sulphate,                                               55
  Barytes,                                                       55
    and Silica Paints in Pittsburg tests,                       172
  Basic Carbonate-White Lead,                                    42
  Benzine,                                                       20
  Benzol,                                                        20
  Blanc Fixe,                                                    60
  Blue Lead, Sublimed,                                           47
  Blue Paint for concrete wall, formula,                        215
  Blue paints in Pittsburg tests,                               142
  Boiled Linseed Oil,                                             2
    Driers in,                                                   28
  Bone Black,                                                    66

  Calcium Carbonate,                                             60
  Calcium Sulphate,                                              60
  Carbon Black,                                                  66
  Cause of rust in steel work,                                  220
  Chalking test for laboratory,                                 149
  Checking and cracking in Pittsburg tests,                     166
  Checking, in Atlantic City tests,                             122
  China Clay,                                                    62
  Chrome Green,                                                  66
  Chrome Yellow,                                                 64
  Coatings for cement and concrete,                             214
  Colored formulas in North Dakota tests,                       190
  Colors, report of, in Pittsburg tests,                        139
  Combination formulas in inhibitive paints,                    231
  Composite formulas in North Dakota tests,                     190
    in Pittsburg tests,                                         142
  Composition of paints, in steel test,                         232
  Conclusion from Pittsburg tests,                              144
  Concrete primer formula,                                      218
  Constants of Pine Oil,                                         18
    Pure Gum Turpentine,                                         19
  Co-operative tests of Driers,                               29-41
  Corn Oil,                                                      16
  Cottonseed Oil,                                                15

  Damp-proofing and Waterproofing,                              214
  Decay of Lithopone paints,                                    124
  Decomposition of Paint,                                       122
  Driers, Co-operative tests of,                              29-41
    in Boiled Oil,                                               28
    Tests of Manganese, Lead and Combination, tables,         24-25
  Drying Properties of Oil,                               1, 26, 27

  Elasticity and Strength of Paint Coating,                     102

  Fence tests of paints,                                        105
    Supervision of,                                             112
  Film sectioning,                                               87
  Film testing results, table,                                   80
  Filmometers,                                                74-79
  Formula for Blue Paint for concrete wall,                     215
    Concrete primer,                                            218
    Para Red Paint for concrete wall,                           217
  Formulas of Atlantic City fence test,                         108
    Tennessee tests,                                       202, 204
    Washington tests,                                      208, 211
  Fume Pigments Paints in Pittsburg tests,                      173

  General results of Atlantic City tests,                       128
  Gloss, in Atlantic City tests,                                122
  Graphite,                                                      66
  Green paints in Pittsburg tests,                              142
  Grinding Pigments,                                             87
  Gums as moisture resisters,                                    84
  Gypsum,                                                        60

  Hailstorm, effects of in North Dakota tests,                  185
  Hospital, painting practice,                                  254
  House paint tests in North Dakota,                            196
  Hydrocarbon Oils,                                              16

  Imperviousness of paint coating,                              100
  Indian Red,                                                    62
  Inert Pigments, use of,                                        99
  Inhibition of rust,                                           222
  Iodine Values of Linseed and Mixed Oils, table,                 8
  Iron Oxide Paints,                                             64

  Japan driers in tests on steel,                               231

  Laboratory tests, panels for,                                 149
  Lampblack,                                                     66
  Laws of Paint Making,                                          93
  Lime action on paint,                                         214
  Linoxyn,                                                       21
  Linseed Oil, boiled,                                            2
    Chemical action of pigments upon,                            91
    Table of Analyses of Various Types of,                        7
    tests of Driers with,                                    24, 25
  Lithopone,                                                     53
    paint in Pittsburg tests,                                   136
    tests at Atlantic City,                                     124
  Lumbang Oil,                                                   12

  Magnesium Silicate,                                            55
  Manufacturing Barytes,                                         55
    Blue Lead,                                                   47
    Bone Black,                                                  66
    Paint Pigments,                                           42-68
    White Lead,                                                  42
  Menhaden Oil,                                                  12
    Constants of, table,                                         14
  Metallic Brown,                                                62
  Microscope, use of in paint laboratory,                        86
  Microscopic examination of paint, preparation for,             86
    measurements of paint sections,                              89
  Mineral Black,                                                 68
    Oils,                                                        17
  Moisture Absorption, tests in,                                 84
    experiments with various Pigments,                           83

  North Dakota Paints tests,                                    182
    test fence,                                                 105
    report of, table,                                       193-195

  Ochre,                                                         62
  Oil and Thinner tests,                                        202
  Oil, Corn,                                                     16
    Cottonseed,                                                  15
    Effects of Pigments on,                                      90
    Linseed,                                                      1
    Linseed, Analyses of Various Types of, table,                 7
    Linseed, Iodine Values of, table,                             8
    Linseed, Tests of Driers with,                           24, 25
    Lumbang,                                                     12
    Menhaden,                                                    12
    Menhaden, Constants of, table,                               14
    Perilla,                                                     21
    Pine,                                                        18
    Rosin,                                                       16
    Soya Bean, and Driers, table,                                 9
    Soya Bean,                                                    7
    Chemical Characteristics of, table,                           8
    Sunflower,                                                   14
    Tung,                                                         9
    Whale,                                                       14
  Oils, Constants and Characteristics of,                         1
    Drying properties of,                                     1, 26
    Hydrocarbon,                                                 16
    In Washington paint tests,                                  210
    Iodine Value of Linseed and Mixed, table,                     8
    Mineral,                                                     17
    Moisture resistance of,                                      84
    Oxygen Absorbing qualities,                                  21
    Outline of tests of paints on concrete walls,               216
  Oxygen Absorption in Oils,                                     21

  Paint Coating, Adhesive power of,                             104
    Elasticity and Strength of,                                 102
    imperviousness of,                                          100
    decomposition of,                                           122
    films, action of water upon,                                223
    permeability of,                                             71
    Testing machine,                                             74
    preparation of,                                              70
    in Hospitals,                                               254
    making, Laws of,                                             93
    Perry's Principles of,                                      100
    pigments,                                                 42-69
    pigments, properties of,                                     42
    preparation for microscopic examination of,                  86
    tests at North Dakota Experiment Station,                   105
    at Washington,                                          207-213
    supervisors of,                                             113
    woods used on,                                         124, 135
  Painting steel plates for tests,                              230
  Paints for cement and concrete surfaces,                      214
    composition of in steel test,                               233
    hiding power of,                                            111
    sanitary value of,                                          252
  Panels for laboratory tests,                                  149
  Para Red formula for concrete wall,                           217
  Paranitraniline paints in Pittsburg tests,                    140
  Paranitraniline Red,                                           64
  Perilla Oil,                                                   21
  Perry's analogies of paint and concrete manufacture,           99
    principles of Paint Making,                                 100
  Petroleum Spirits,                                             20
  Photomicrographs,                                         89, 165
  Pigment contention, the,                                      105
    grinding,                                                    87
  Pigments,                                                   42-69
    as stimulators of rust,                                     223
    Chemical action of upon Linseed Oil, table,                  91
    Effects of on Oil,                                           90
    inert, use of,                                               99
    moisture experiments with, table,                            83
    percentages of Oil required for grinding,                    68
    re-enforcing,                                                89
    report of results of steel paint tests,                 236-251
    Water resistance of,                                         81
  Pine Oil,                                                      18
  Pittsburg fence tests,                                        107
  Polar Micro-Examinations and Photomicrographs,                 89
  Primer for concrete,                                          218
  Properties of Paint Pigments,                                  42
  Prussian Blue,                                                 66

  Red Lead,                                                      64
  Reductions used in fence tests,                               111
  Re-enforcing Pigments,                                         89
  Results of new test at Atlantic City test fence in 1910,
    table,                                                  178-181
    Pittsburg tests,                                            135
    steel test plates,                                          232
  Rosin Oil,                                                     16
  Rust, cause of in steel work,                                 220
    inhibition of,                                              222
    stimulation of,                                             223

  Sanitary value of paints,                                     252
    wall paints,                                                254
  Sienna,                                                        62
  Silex,                                                         60
  Silica,                                                        60
  Silica and Barytes Paints in Pittsburg tests,                 172
  Solvent Naphtha,                                               20
  Soya Bean Oil and Driers, table,                                9
    Chemical Characteristics of, table,                           8
  Steel Paint test, rating report,                              234
    reports on pigments used,                               236-251
  Steel paint, result of tests at Atlantic City,           234, 235
  Steel, preparation of for paint tests,                        228
    water contact and paint,                                    224
  Structural steel paint tests,                                 220
  Sublimed Blue Lead,                                            47
  Sublimated White Lead,                                         46
  Suction varnish,                                              215
  Sunflower Oil,                                                 14
    Constants of, table,                                         15
  Supervisors of paint tests,                                   113

  Table Analysis of Averages in Atlantic City Steel Paint
    test,                                                  235, 236
    Analyses of Corn Oil,                                        16
    Analyses of Debloomed Mineral Paint Oil,                     18
    Analysis of Iron Oxide Pigments,                             63
    Analyses of Oils used in Washington tests,                  211
    Analyses of Petroleum Spirits,                               20
    Analyses of Rosin Oil,                                       16
    Analyses of various types of Linseed Oil,                     7
    Analyses of wood Turpentine,                                 19
    Atlantic City test fence formula,                           108
    Chemical Characteristics of Soya Bean Oil,                    8
    Comparative spreading rates of White Paint in Pittsburg
      tests,                                                    148
    Composition of Blue Lead,                                    49
    Composition of paints in Atlantic City Steel test,          233
    Constants of Cottonseed Oil, table,                          15
    Constants of Menhaden Oil,                                   14
    Constants of Pine Oil,                                       18
    Constants of Sunflower Oil,                                  15
    Constants of Whale Oil,                                      14
    Co-operative drying tests,                                32-41
    Excluding tests for moisture absorbed,                       84
    Fineness for grinding pigments,                              87
    Formulas in Tennessee tests,                                204
    Iodine Value of Linseed Oil and Mixed Oils,                  84
    Moisture experiments with various pigments,                  83
    Paint section measurements under microscope,                 89
    Percentages of Oil required for grinding various dry
      pigments,                                                  68
    Permeability of Paints,                                      72
    Ratings of Atlantic City Steel Paint test,                  234
    Report of North Dakota test fence,                      193-195
    Results of Atlantic City test fence,                   130, 131
    Results of new tests at Atlantic City test fence in
      1910,                                                 178-181
    Results of second annual inspection Atlantic City test
      fence,                                                    133
    Results of second annual inspection in Pittsburg tests,     145
    Showing action of various pigments upon Linseed Oil,         91
    Soya Bean Oil and Driers,                                     9
    Tests of Linseed Oil and Manganese, Lead and Combination
      Driers,                                                24, 25
  Talcose,                                                       55
  Tennessee Paint tests,                                    201-206
  Test Fences in Paint Experiments,                             105
    at Atlantic City,                                       114-134
    at Pittsburg,                                           135-148
    at Washington,                                          207-213
    Cement and concrete,                                        214
    in Tennessee,                                           201-206
    laboratory, chalking,                                       149
    North Dakota,                                               182
    of Oil and Thinners,                                        202
    of various pigments in steel paint,                     236-251
    panel sections for,                                         149
    Structural steel paints,                                    220
    Water pigment,                                              226
  Thinner, Wood Turpentine as a,                                202
  Tung Oil,                                                       9
  Tung Varnishes,                                                11
  Turpentine,                                                    18

  Ultramarine Blue,                                              66
  Umber,                                                         62

  Varnishes from Tung Oil,                                       11
  Vermilion, American,                                           64

  Wall paints,                                                  252
  Wall paper, defects of,                                       255
  Washington Paint tests,                                   207-213
  Water, action of upon paint films,                            223
    contact with steel and paint,                               224
    resistance of Pigments,                                      81
    tests,                                                      226
  Water-pigment tests,                                          226
  Waterproofing and damp-proofing,                              214
  Whale Oil,                                                     14
  White Lead, Basic Carbonate,                                   42
    Basic Sulphate,                                              46
    Mild Process,                                                46
    Quick Process,                                               45
    in Pittsburg tests,                                         139
    in North Dakota tests,                                      190
    Paints, checking in Pittsburg tests,                        172
    processes of manufacture of,                              43-46
  Whiting,                                                       60
  Wood Turpentine,                                               19
    experiments with as a thinner,                              202
  Woods used in paint tests,                               124, 135

  Zinc Chromate,                                                 64
  Zinc Lead White,                                               51
  Zinc Oxide,                                                    51



  +------------------------------------------------------------------+
  |                     TRANSCRIBER'S NOTES:                         |
  |                                                                  |
  | * Page 25, Table VIII: the table header row contains duplicate   |
  |   values which may be a typographical error.                     |
  | * Pages 86 and 87: two section titles are followed by numbers    |
  |   without any obvious reason. These have not been deleted.       |
  | * The original spelling (including hyphenation) has been         |
  |   preserved, except as indicated below. Some minor inconsisten-  |
  |   cies and typographical errors have been corrected silently.    |
  | * Changes made to the text:                                      |
  |   * Page 26: 'as discolored and turned brown' changed to 'was    |
  |     discolored and turned brown'.                                |
  |   * Page 87, table 3rd row: '0.00067--' changed to '0.00067'.    |
  |   * Page 94, exposition: some elements re-arranged for better    |
  |     readability.                                                 |
  |   * Page 124: the note at the bottom of the page has been moved  |
  |     to directly underneath the first paragraph.                  |
  |   * Page 130: 'MacNichol' changed to 'Macnichol' as elsewhere.   |
  |   * Page 137 (caption): 'Pittsburgh' changed to 'Pittsburg' as   |
  |     elsewhere in text (and in illustration itself).              |
  |   * Page 142: 'prussian blues' changed to 'Prussian blues'.      |
  |   * Page 177: 'pages 174 to 177' changed to 'pages 178 to 181'.  |
  |   * Page 211: one footnote anchor changed from '*' to '[32]' as  |
  |     others in row.                                               |
  |   * Page 230, formula: '4500' changed to '5400'.                 |
  |   * Page 234, table: row for Panel No. 2000: '}' inserted for    |
  |     combined rows.                                               |
  |   * Index: changed to agree with text: 'determinating' to        |
  |     'determining', 'Derbloomed' to 'Debloomed', 'Filometers' to  |
  |     'Filmometers', 'Parilla Oil' to 'Perilla Oil'. 'Grinding     |
  |     Pigments' moved to proper alphabetic location.               |
  |                                                                  |
  +------------------------------------------------------------------+





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