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Title: The Art of Lead Burning - A practical treatise explaining the apparatus and processes.
Author: Fay, C. H.
Language: English
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The Art of Lead Burning
_A PRACTICAL TREATISE EXPLAINING THE APPARATUS AND PROCESSES._
_52 ILLUSTRATIONS._
By C. H. FAY
Reprinted from
_The Metal Worker, Plumber and Steam Fitter_.
PUBLISHED BY
DAVID WILLIAMS COMPANY,
232-238 William St., New York,
1905.
Copyrighted, 1905.
By
David Williams Company.
PREFACE.
The mystery which has always surrounded the work of the lead burner,
like that of all other handicrafts outside of ordinary occupations,
dissolves under the light of a full knowledge of the causes and effects
that have a bearing upon it. While different works have treated on lead
burning, it is the object of this special treatise to explain fully in
detail every part of the apparatus and fixtures in common use, as well
as their application, so that the careful reader may understand and
acquire the art of lead burning by observing scrupulously the rules laid
down and devoting sufficient time to practice to master it. This
instruction, given by text and illustration, is only presented after the
dangerous power of hydrogen gas when misused is thoroughly impressed on
the reader. It would be well for all who hope to become lead burners to
devote several evenings, with an interval between, to a thorough study
of the chapters on hydrogen gas and its properties before taking any
further steps. To those who have not had previous experience with
chemicals and gases this preliminary study is indispensable for their
own safety, for the successful operation of the apparatus and to insure
satisfactory work. When fully familiar with the properties of hydrogen
gas and the necessity of being careful when it is used little difficulty
will be experienced in acquiring a full knowledge of the apparatus and
fixtures. The art of burning the lead can only be acquired by practice,
and either quickly or slowly, as the operator may be quick and skillful
in acquiring any handicraft. In addition to describing what has been
common practice for many years, the treatise contains a description of a
new machine and burner which has only recently become available to lead
burners. It also describes the method of lead burning with the use of
illuminating gas and a soldering flux. A chapter is devoted to soft
soldering and Britannia metal work, which is largely used in the
equipment of bars and restaurants, the various joints being more easily
made with a blow pipe than by any other method. As the workman who hopes
to profit by reading this book can by a little negligence make a great
deal of trouble for himself and others, caution and great care are
advised whenever he is at work.
CONTENTS.
CHAPTER. PAGE.
I. Introduction 9
II. The Apparatus 15
III. Hydrogen Gas 18
IV. The Construction of the Generator 26
V. Making the Gas to Burn the Generator 39
VI. Connecting the Apparatus 55
VII. Charging the Generator 64
VIII. The Flame and Its Management 73
IX. The Different Kinds of Seams 80
X. Pipe Seams 100
XI. Acid Chamber Work 108
XII. Special Hydrogen Apparatus and Burner 119
XIII. Soft Soldering with the Mouth Blow Pipe 127
CHAPTER I.
INTRODUCTION.
In compiling a treatise on the subject of lead burning too much stress
cannot be laid upon the fact that the greatest care must be taken to
observe the smallest details and to follow carefully every suggestion in
regard to safety. I am aware of the responsibility resting upon me in
placing this article into hundreds of hands, comparatively ignorant of
the danger involved in handling so much hydrogen, without thoroughly
instructing them in detail as to its use. I may be excused, therefore,
if, for that reason, some of the explanations are so simple as to seem
ridiculous; but my aim is to present to the trade a treatise that can be
relied upon to be free from theory that has not been thoroughly tried
and tested, so that the beginner can be sure that, if he follows
directions as printed, nothing but satisfaction to him can result.
Study the Chapter on Hydrogen Gas.
I cannot too strongly recommend that the beginner study the chapter on
hydrogen gas until the main points are memorized and clearly understood.
The experiments should be performed and the result carefully noted for
future reference before attempting to use the generator. It is time well
spent to master the technical parts thoroughly before attempting the
mechanical part. Then when a man takes up the mechanical he will do so
with an intelligent understanding of what he is doing, and any little
trouble which may then arise can be quickly overcome.
Another thing to be observed is to avoid nervousness. A nervous person
cannot do this work with any degree of satisfaction, as it requires a
cool head and a steady hand and a vast amount of patience to burn the
upright and inverted seams.
Lead Burning Explained.
Lead burning is the process of fusing two pieces of lead together
without the use of solder. The process consists in melting the edges
together, a drop at a time, and when done with hydrogen gas and the blow
pipe is called the “autogenous process.” Lead can be fused with gasoline
or illuminating gas by the use of the compound blow pipe; but, as
ordinary gases give an oxidizing flame and require a flux, it is not
considered a practical method.
[Illustration:
_Fig. 1.—Lead Burning Apparatus._
]
Lead is used extensively in lining tanks made to contain pickle dips,
hot cyanide solution, storage batteries, acid tanks for manufacturing
jewelry and water closet tanks, as water in many cases contains large
quantities of lime and other deposits which rapidly destroy the solder
used on copper linings. Tanks used for the above purposes must be lined
with lead and the seams burned, as acids attack the tin in solders and
destroy them. The demand for the work is rapidly increasing where it is
introduced. I have demonstrated to many manufacturers that this is the
cheapest method known, as it gives a permanent solution of the problem
how to keep a chemical tank tight.
Method of Making Lead Lined Tanks.
The most common method resorted to in many large factories is to make
the tanks out of very heavy cypress lumber, free from any knots or
blemishes. The joints are carefully dovetailed and fitted together, and
long bolts are used to draw the joints and keep them from leaking.
Usually it takes from three to four days to complete one small tank,
only to have it leak in a few months; whereas the same tank can be built
in a few hours of any cheap lumber, and then, when it is lined with lead
of a proper thickness and the seams burned it will usually last for an
indefinite period, thereby saving floors and, many times, costly plating
solutions.
The most common argument put forth by manufacturers is that the bottoms
of lead lined tanks are soon cut out, owing to dropping sharp pieces of
metal into them. This difficulty can be best overcome by placing a
slatted bottom of wood in the tank, holding the same in place with
strips of sheet lead, one end of which has been previously burned to the
bottom of the tank. These strips are to be brought up through the slats
and then bent over the top of them. This will keep the wood from
floating, and is the only practical way to do it, as the false bottoms
soon decay, and can be easily removed and replaced by simply bending
back the strips of lead.
General Remarks.
Soft solder, as referred to here, means solder that melts at a
temperature of 300 degrees or less, and is so called because of the low
heat required to fuse the solder. It is used almost exclusively on the
quick melting metals and compositions, such as block tin pipes and
Britannia metal. It is also used by pattern makers in soldering white
metal, as it requires but very little heat to sweat it through heavy
articles. It should not be used to join any pipes which convey hot water
or other hot liquids, as it is readily acted upon and destroyed. (The
composition of these solders is explained in a special chapter.)
The chapters on blow pipe work, also on bar work, will alone turn many
dollars into the pockets of the plumbers who have courage and ambition
to acquire this line of work. Many times small leaks occur in difficult
places that can be readily repaired by the use of the blow pipe and a
common candle.
The lining of bars with Britannia metal is coming more and more into
general practice, and it usually requires a specialist in this line to
do the work. The soldering of this metal with a blow pipe and an alcohol
torch is an easy matter, and is described in a special chapter.
There is no reason why this work should not be done by a plumber,
particularly in small cities and towns, and to aid such as have not had
the opportunity to familiarize themselves with such work I append such
diagrams as may seem useful and necessary.
CHAPTER II.
THE APPARATUS.
The apparatus used for lead burning is illustrated in Fig. 1. It
consists of a gas generator, A; an air holder, B, and pump, C; mixing
fork, _e_, and necessary cocks, _f_ and _g_; combined scrubbing cup and
fire trap, _h_; blow pipe and tips, _i_.
The generator consists of an acid chamber, _j_, and a gas chamber, _k_.
These are connected with an acid supply pipe, _l_, which conducts the
acid from the acid chamber to the gas chamber, and also serves as a
balance pipe.
This feature makes the generator automatic in its action, for as soon as
the gas in the gas chamber gets up sufficient pressure, the acid in the
gas chamber _k_ is driven slowly back through the acid supply pipe _l_
and up into the acid chamber _j_, where it is held until gas is used.
When the acid descends and submerges the zinc more gas is generated,
replacing that which has been used. This form of generator will never
blow acid like the floating generator.
The requirements of a hydrogen generator for lead burning are that it
should be safe, economical and automatic in its action. It must be so
constructed that it will generate gas enough to keep the supply
constant, and deliver it at sufficient pressure to keep the flame
steady. It must also be provided with a combination fire trap and
scrubbing cup. This will prevent the explosion of the generator by
firing the gas in the hose. This trap must be partly filled with a
solution of blue vitriol to act as a precipitation cup. (This is treated
under the head of “Scrubbing Cup.”)
The chief danger with an apparatus of this sort is its liability to
accident by the careless use of the gas, and, as a mixture of hydrogen
and air is very explosive, great care must be taken to exhaust all the
air in the generator and tubes before attempting to light the gas at the
blow pipe. The only way to make sure that the air is exhausted is to
test the gas, as described under the head of “The Flame and Its
Management.”
A Few Cautions.
It is a very sensible idea to keep spectators away from the generator,
as they are very apt to strike matches or tread on the tubes, in spite
of warnings to be cautious, for if there should be a leak, even so
slight as to be hardly detected, it would cause a violent explosion, and
as hydrogen is both odorless and colorless, this could easily happen
without being noticed. This is probably the origin of the apparent
secrecy with which a lead burner usually surrounds himself.
If an explosion should occur in the tubes and they should catch fire,
the operator must have presence of mind enough to reach the gas cock on
the generator and close it. If gas explodes in the generator, all that
can be done is to dodge the flying pieces and make a new generator. If
such an incident should occur and vitriol should spatter on the person
doing the work, or his assistant, a solution of bicarbonate of soda or
common washing soda should be at once applied to the wounds. If that
cannot be procured, grease or oil of some kind should be used without
delay, rubbing it on the spots where the acid burns, and this will
neutralize the acid and so prevent it doing further damage. There should
be no trouble of this sort in the hands of a careful workman. The
watchword should be, “Test the gas before using.” If this is done,
explosions will never occur.
CHAPTER III.
HYDROGEN GAS.
This element was discovered by Cavendish in 1766, and was called by him
inflammable air. The name hydrogen is derived from two Greek words, one
signifying “water” and the other “to generate,” on account of its
forming water when burnt. It occurs in its free state in the bases of
volcanoes, and by the aid of the spectroscope has been detected in the
sun and stars. It chiefly exists in combination with oxygen as water,
and is an important constituent of all vegetable and animal substances.
Hydrogen is obtained by the decomposition of water in various ways. On a
large scale, nearly pure hydrogen may be prepared by passing steam over
charcoal, or coke, heated to a dull redness. If the temperature be kept
sufficiently low hydrogen and carbon dioxide will be the sole products,
and the latter may be removed by causing it to traverse a vessel filled
with slaked lime, but if the temperature be allowed to rise too high, or
an excess of air be admitted, carbon monoxide is also produced, and
cannot be removed from the mixture.
Pure hydrogen is a colorless, odorless, transparent and tasteless gas,
and has never been liquefied. It is very slightly soluble in water. It
is the lightest of all known bodies and is not poisonous, although it
cannot support life, and if mixed with a certain proportion of oxygen it
can be breathed for a considerable length of time without inconvenience.
It is highly inflammable, and burns in the air with an almost colorless,
nonluminous flame, forming water. A burning taper is extinguished when
plunged into hydrogen, and all bodies which burn in the air are
incapable of burning in hydrogen.
Hydrogen does not spontaneously enter into reaction with any of the
elements, although it has a powerful affinity for several of them. Thus,
when hydrogen and oxygen are mixed nothing occurs, but if a lighted
splint is introduced a violent explosion ensues, water being produced.
Similarly chlorine and hydrogen are without action upon each other in
the dark, but if the mixture is exposed to a bright light, or if heated
by the passage of an electric spark, the gases are at once combined with
explosive violence, forming hydrochloric acid.
Hydrogen is usually prepared by the action of zinc or iron on a solution
of hydrochloric or sulphuric acid. All metals which decompose water when
heated readily furnish hydrogen, on treatment with hydrochloric or
sulphuric acid. Many other metals enter more or less readily (although
none so readily) into reaction with these acids. Also, many other acids
than sulphuric or hydrochloric acids may be used, but none acts so
quickly. In all cases the action consists of the displacement of the
hydrogen of the acid by the metal employed, and if the acid is not one
which can enter into reaction with the displaced hydrogen, the latter is
also evolved as gas.
If pure gas is required it is necessary to employ pure zinc or iron, as
the impurities in the ordinary metal communicate an extremely
disagreeable odor to the gas.
The pure gas is not absolutely essential for lead burning, and owing to
their being much cheaper, and also on account of their increased
quickness of action, the commercial qualities of sulphuric acid and zinc
are employed in the generator described.
The commercial zinc is known as spelter and is sold in pigs or blocks,
which are easily broken into fragments, like stove coal, with a heavy
hammer. The commercial sulphuric acid is known as oil of vitriol and is
sold by the pound. The acid cannot be employed in its pure state, but
must be reduced with water in the proportion of one part of acid to
seven parts of warm water. They must be mixed by adding the acid slowly
to the water; never the water to the acid. The combination of acid and
water enters at once into reaction and always generates heat, and the
result of adding water to acid would be small explosions. There would be
danger of the acid flying on one's clothes or into the eyes. The mixture
should never be stronger than six parts of water to one of acid.
The beginner will observe from the above that the generator cannot be
crowded by making the acid solution strong. Hydrogen is a peculiar gas
and also a dangerous one for one ignorant of its peculiarities to
experiment with, and in order to thoroughly understand it the following
experiments should be demonstrated, which can be done with little
expense. The beginner should note the result of each experiment as
demonstrated, and carefully commit the same to memory for future
reference.
Experiment 1.
_Test for Hydrogen._—Fill a small jar or wide mouthed bottle with
hydrogen. This is done by first filling the bottle with water, inserting
the end of the tube from the hydrogen generator, having first exhausted
the air in the tube, then quickly inverting the bottle and placing the
neck, Fig. 2, in a pan of water (A); the water will stay in the bottle.
Now turn on the hydrogen. The gas, being lighter than water, will rise
to the top of the bottle (B), drive out the water, and replace it with
pure hydrogen, which should be free from air. Remove the bottle from the
pan of water, keeping it inverted. Thrust a lighted splint into the
bottle. The gas will light and burn at the mouth of the bottle. If the
splint is thrust far into the bottle it will go out. Drops of water
collect in the bottle. Burning is a union with oxygen; therefore, the
burning of the hydrogen shows that it has an affinity for oxygen. The
splint goes out because the hydrogen does not support combustion. _If no
air is allowed to get into it the gas cannot burn or explode._
[Illustration:
_Fig. 2.—Experiment No. 1._
]
Experiment 2.
[Illustration:
_Fig. 3.—Experiment No. 2._
]
_Proving That Hydrogen is Lighter Than Air._—Bring an inverted bottle of
hydrogen close to an empty bottle, also inverted, Fig. 2. Gradually tip
the bottle containing hydrogen (A) until it is brought to an upright
position beneath the empty bottle. Test the bottles for hydrogen. The
hydrogen will be found in the bottle (B) that was at first empty,
proving that _hydrogen is lighter than air_, as it has risen in the
empty bottle, displacing the air that was in it. If the bottle of
hydrogen is left in an upright position without a cover for a few
moments the gas will entirely disappear.
Experiment 3.
[Illustration:
_Fig. 4.—Experiment No. 3._
]
_The Effect of Mixing Hydrogen and Air._—Half fill a bottle with water
and invert it in a pan of water, Fig. 3, leaving the upper half filled
with air. Displace the air in the bottle with hydrogen, then thrust a
lighted splint into the bottle, and the gas will light with an
explosion. When the bottle was half filled with water the other half was
air. The hydrogen took the place of the water, so that the bottle
contained equal quantities of hydrogen and air. When the hydrogen was
lighted it combined with the oxygen in the air. The union of the two
gases caused the explosion, proving that the combined gases are very
explosive.
Experiment 4.
_To Make Hydrogen From Water._—Drop a piece of potassium into a little
water and cover it. The potassium floats on the water and soon burns.
Potassium acts vigorously on cold water, setting free hydrogen, and
unites with parts of it to form “caustic potash.”
CHAPTER IV.
THE CONSTRUCTION OF THE GENERATOR.
The construction of the generator is the first step in the mechanical
part of the business, and to simplify this a complete set of reference
drawings has been constructed and is herewith given. The assembling of
the parts should be clear, with the assistance of the perspective
drawing of the completed apparatus, and any mechanic of ordinary ability
should be able to construct this generator without any trouble. The
following bill of material should first be purchased:
One ⅞-inch whitewood board 10 inches wide and 8 feet 6 inches long.
One ½-inch whitewood board 12 inches wide and 4 feet 6 inches long.
One piece of 6-pound sheet lead 3 feet wide and 6 feet 6 inches
long.
Three ⅛-inch female hose end gas cocks.
One piece of ⅛-inch brass tubing 2 feet long.
One foot of ¼-inch lead pipe.
One 4-inch charging screw.
One 1¼-inch cleaning screw.
Making the Charging and Cleaning Screws.
These goods can be readily purchased from dealers, with the exception of
the charging and cleaning screws. They can be made in any brass foundry.
The only difference between the charging and cleaning screws is the
size. The charging screw, Fig. 5, should be at least 4 inches in
diameter, or large enough to pass the hand through, while the cleaning
screw should be 1¼ inches in diameter, or large enough to pass over a
1-inch pipe. A piece of sheet lead is fitted into the cover, as shown at
_a_, to protect the metal from the acid. Soft putty is used for a
packing, as shown in Fig. 5.
[Illustration:
_Fig. 5.—The Charging Screw._
]
The best, although a more expensive, charging screw is shown in Fig. 6.
As will be seen from the cut, it consists of a base, _k_; cover, _d_;
clamp, _e_, and screw, _f_. The base is simply a plain iron or brass
ring, 4 inches in diameter, ⅛ inch thick and 1 inch high. The bottom is
to be faced smooth, while the top is recessed 3-16 inch deep to receive
the sheet lead and packing of putty, as at _a_. Two nubs, _b_ and _b_,
are cast on opposite sides, as shown, to act as grips for the clamp _c_.
These nubs are ¾ inch long and project out from the body of the base ¼
inch, and are made sufficiently strong to stand the strain of the screw.
The cover _d_ is made of the same material as the base, the center being
raised, as shown, to give it strength. Cast directly in the center and
on the top is the nub _e_, ⅝ inch high and ⅝ inch in diameter. This is
drilled to receive the ⅜-inch screw _f_. A groove 1-16 inch wide and
1-16 inch deep is cut all around the bottom of the screw, as shown at
_i_. A hole is then drilled through the side of the nub _e_, and in line
with the slot _i_. A pin can then be driven through the hole and will
pass through the slot _i_, making a swivel joint that will connect the
cover and screw together. The screw _f_ is made of ⅜-inch round iron
sufficiently long to give an action of about 1 inch. The top at _n_ is
filed square to receive a wheel such as is used on a common gate valve.
A long thread should then be cut on this screw. The clamp _c_ is made a
half circle in shape, so as to clear the cover with ease. It should be ¾
inch wide, flat on the under side, while the top side should have a rib
cast on it to prevent springing. The top at _g_ should be reinforced
with metal and made heavy enough to stand drilling and tapping to
receive the screw _f_. A wood pattern can be made for these parts, and
they can then be molded in any brass or iron foundry. In making the
patterns they should be cut down as much as possible, so as to make the
finished article as light as is consistent with the strength required.
The same directions will answer for the cleaning screw. The hole to
receive the sheet lead over the cleaning screw should not be over 1½
inches in diameter, and the rest of the screw should be made in
proportion to this hole. The advantage of this screw over others is that
it does not wrench the sheet lead in making it up, and, owing to its
construction, it is always sure to make a tight joint without straining
the generator.
[Illustration:
_Fig. 6.—The Best Charging Screw._
]
Building the Frame.
The frame can be made of galvanized iron, but wood is much superior, as
it retains the heat generated in the gas chamber much better. To make
the frame take the ⅞-inch board and cut off two pieces, 10 inches
square, A and B in Fig. 8; 5 inches from one side and 2 inches from the
back of one of these pieces bore a 1½-inch hole, C, and countersink it.
This is for the acid supply pipe to pass through. These pieces are
intended for shelves upon which to rest the acid and gas chambers. Cut
the remaining board into two pieces 38 inches long. Lay these two boards
together. Five inches from the side and 3 inches from the bottom bore a
1½-inch hole, _d_. Then saw out a V-shaped piece, Fig. 7. This will form
the legs of the generator.
[Illustration:
_Fig. 7.—Making the Acid Chamber._
]
Take a square, and 12 inches from the top of these boards draw the lines
_e_ and _e_. Twenty-two inches below these lines draw the lines _f_ and
_f_. These lines represent the tops of the shelves. The shelves should
be nailed or screwed into place. The shelf B should be placed on the
top, keeping the hole C to the back. Take the ½-inch board and cut two
pieces to measure 12 × 13 inches and two pieces 11 × 12 inches. These
form the sides of the acid and gas chambers. The two 12 × 13 inch boards
form the sides of the acid chamber and the 11 × 12 inch boards the sides
of the gas chamber.
Directly in the center and 1¾ inches from the bottom of one of the 11 ×
12 inch boards bore a 1½-inch hole. The remaining piece should be sawed
out, leaving a hole at _g_. This is so that the board can be removed in
case of a leak without disturbing the cleaning screw. These pieces
should be fitted to their places with round head screws, and if properly
done will form an acid chamber which will measure 10 × 10 × 12 inches,
and the gas chamber will measure 10 × 10 × 10 inches. The acid chamber
must be larger than the gas chamber, to allow the full charge of acid to
be used without overflowing.
[Illustration:
_Fig. 8.—Making the Shelves and the Perforated Bottom._
]
Now fit the sheet lead. Six-pound is plenty heavy for this generator and
will last a lifetime. Cut it as shown in Fig. 8, A and B. Form the lead
so that the seams when finished will come on the outside, as in case of
a leak in a seam it can then be easily repaired by removing one of the
boards. The projecting edges of lead should be dressed over the edges of
the top to protect the wood from the acid, but do not fasten them, as
the tanks will have to be removed and the seams burned.
Now cut the piece of lead C to form the top of the gas chamber. None is
needed for the acid chamber, as it must be left open so that no
resistance will be offered to the action of the gas on the acid. Five
inches from the side and 2 inches from the back of this piece cut a
hole, _d_, Fig. 8, 1¼ inches in diameter, and dress it up with the
bending iron to 1½ inches in diameter, taking care to preserve the
thickness of the metal. This is for the acid supply pipe to pass
through.
Three inches from the side and 3 inches from the front cut a ⅛-inch
hole, _e_. This is the gas outlet. Three and one-half inches from the
opposite side and 4 inches from the front cut the hole _f_, 2¾ inches in
diameter. Dress this up and over the flange of the charging screw _a_,
Fig. 6. This may seem a difficult thing to do, but lead must be worked
slowly. Heating the lead while dressing it will help wonderfully. If it
is not possible to make a good job in this manner, then cut the hole 4
inches in diameter and burn in a collar sufficiently big to dress over
and cover the flange of the screw. This is to prevent acid from coming
into contact with the screw and destroying it. Treat the cleaning screw
in the same manner. The location of this screw is in the center and as
close as possible to the bottom of the gas chamber, as shown in Fig. 8
at _j_.
[Illustration:
_Fig. 8½.—Showing the Perforated Spelter Shelf in Place in the
Generator._
]
It is necessary to have a false perforated bottom in the gas chamber to
rest the zinc upon and also to keep it above the solution. To make and
support this bottom take a piece of sheet lead 14 inches square, as
shown in Fig. 8, and form it in the shape of a pan, which will drop
easily into the gas chamber _k_, Fig. 8½. A piece of 1½ or 2 inch lead
pipe, 2 inches long, _n_, should be burned on the center of the false
bottom, to prevent the center from sagging with the weight of zinc. Then
punch the bottom O, Fig. 8, full of ¼-inch holes. A 1½-inch hole, _y_,
should also be cut in line with the holes for the acid supply pipe.
Remove the tanks and burn the seams. Place the tanks back in place. Then
take a piece of the ⅛-inch brass pipe, 1½ inches long. Cut a thread on
one end, tin the other end, and burn it to the top of the gas chamber at
_e_; also the collar for the charging screw. Then place the perforated
bottom in the gas chamber, taking care to keep the holes for the acid
supply pipe in line. Do not make any mistake in putting in this bottom.
Its use is to act as a shelf to hold the zinc, and if put in properly it
will hold the zinc about 2 inches above the real bottom. The top of the
gas chamber _c_ should then be burned in. Now by measuring find the
exact length of the acid supply pipe, Fig. 7, _i_. This pipe should
extend from the bottom of the acid chamber _o_ to the bottom of the gas
chamber _p_, as shown in Fig. 7. From one end of this pipe several
V-shaped pieces should be cut, _p_, about 1 inch deep.
This is one of the most particular parts of the apparatus, as this is
where the automatic action comes in, and great care must be taken in
cutting these holes not to have any of them come closer to the
perforated bottom than 1 inch. If this were not observed the acid would
be constantly in contact with the zinc, and would rapidly get up
pressure of gas sufficient to blow acid out of the upper tank, and the
extra gas would escape through the acid supply pipe in blows. In fact,
it would make the generator useless. This is the trouble with the French
apparatus. The acid, having no place to expand in, is constantly coming
into contact with the zinc, and unless the gas is being used as fast as
generated it will blow acid out of the acid holder, making a bad mess,
besides being very wasteful.
Now flange the other end of this pipe to fit the countersunk bottom of
the acid chamber. Place the pipe in position and burn it to the bottom
of the acid chamber and to the top of the gas chamber _n_, Fig. 7. One
of the ⅛-inch gas cocks should be screwed on the brass nipple on top of
the gas chamber. This will complete the gas generator. It will make a
better job if the back of the generator be boarded tight and a door made
to fit the space between the bottom of the acid chamber and the top of
the gas chamber in front. It is very convenient to have it fixed in this
manner, as in shipping it from one point to another the tubes and other
incidentals can be placed in the space so made and shipped with safety.
There is no objection to the acid and gas chambers being made in the
shape of cylinders, instead of square, if so desired, but if made
circular they should be made to fit the frame tightly to prevent jarring
and eventually breaking the seams.
CHAPTER V.
MAKING THE GAS TO BURN THE GENERATOR.
In towns supplied with illuminating gas it is a comparatively simple
operation to burn the lead lining for the generator, but for the
convenience of those who cannot obtain gas it is necessary to give some
method by which the generator can be burned. The method described will
answer for illuminating gas as well as for gasoline.
To generate gas from gasoline is a simple operation. To do this, take a
common 1-gallon oil can, remove the top of can screw and punch a ¼-inch
hole in the center of it. Then make a tube of tin that will pass through
this hole, sufficiently long to extend half way to the bottom and
project 2 inches outside of can screw, and solder this tube in place.
This projecting tube is for the purpose of connecting to the air holder.
Remove the spout of the can and replace it with one to which the hose
can be connected. Now fill the can two-thirds full of gasoline, but not
full enough to cover the gas outlet, else it would be likely to force
gasoline out instead of gas.
After this is done, screw the can screw in place, the long end of the
tube extending into the gasoline, as shown in _j_, Fig. 9. A hose
connection is now to be made with an air holder. As it is necessary to
have an air holder both for this process and the hydrogen gas process,
methods will be described for making air holders which can be used for
either.
[Illustration:
_Fig. 9.—Gas Apparatus for Burning the Generator._
]
Air Holders.
Different lead burners have different views on this subject. Some prefer
the bellows, with a contained air holder; some the air holder built like
a gasometer, while others use an air holder similar to the generator in
construction. These all have their advantages. For my part, I own and
use all three.
The advantage of the bellows is that it can be easily transported and
does the work perfectly, but it requires constant pumping, which soon
tires the helper, and for that reason could not be used on jobs
requiring more than four or five hours' labor.
The gasometer style of air holder is the easiest to use, if one does not
employ a helper and has a large amount of work to do. The pressure can
be regulated to suit the work by placing one or more weights upon it
until the desired pressure is obtained. It does not require pumping up
more than three or four times a day, which is its principal virtue. It
is a perfect shop apparatus. Its disadvantage is that it requires a
large quantity of water to fill it, which is not always available, and
when full it is so heavy that it requires a truck to move it around.
By far the best air holder is the one shown as part of the apparatus in
Fig. 9, and illustrated separately in Fig. 10. This only requires a few
pails of water to fill it, and the exact pressure of the gas can be had
by building it the same hight as the hydrogen gas generator. It does not
require constant pumping, and I recommend this air holder for general
use, as possessing more advantages, with less trouble, than any other
air holder in use. However, all three will be described, and the
beginner can make the one most suited to the material available.
Air Holder No. 1.
The beginner will notice in Fig. 10 that this air holder is so
constructed that it gets its air pressure direct from the head of water,
and also that this pressure can be varied by making the connecting piece
of pipe longer or shorter, as may be desired. Of course, the pressure
will vary slightly as the water descends into the air chamber, but not
enough to make it objectionable, as it will be the helper's duty to
watch the water line and renew pumping as often as the water falls below
a certain point.
To make this holder, a tank, _a_, Fig. 10, 12 inches high and 18 inches
in diameter, should be constructed of galvanized sheet iron. On this
tank double seam a flat bottom. The top must be raised slightly, as
shown, to give it strength. This can be done with the raising hammer, or
it can be done by making the circle for the top ¾ inch larger than the
bottom, then making a cut to the center. It can then be drawn together
and riveted in any desired pitch. A hole must be punched in the center
of this top large enough to receive a 1-inch galvanized pipe, _b_. Six
inches apart and 2 inches from the edge punch two holes, _c_ and _d_,
large enough to receive pieces of ⅜-inch galvanized pipe. This top
should then be fitted and placed on the body of the tank.
[Illustration:
_Fig. 10.—Air Holder No. 1._
]
Take a piece of 1-inch galvanized pipe, _e_, sufficiently long to touch
the bottom and projecting 1 inch out of the top of the tank, cut a
thread on the projecting end and drill the other end full of ¼-inch
holes, _f_, to the hight of 1 inch, to allow the water to flow freely.
This pipe rests on the bottom of the lower tank and carries the weight
of the upper tank. Solder this pipe in place. Then take two ⅜-inch
nipples, 1 inch long, and solder them into their places, and on these
nipples screw two ⅜-inch hose end gas cocks, _c_ and _d_. One of these
cocks is for the purpose of connecting to the air pump, and the other to
the mixing cock. As close as possible to the bottom of the tank solder
in a ½-inch coupling, _g_. Into this coupling screw a plug. This is for
the purpose of draining the tank when out of use.
Now make another tank, _h_, 19 inches in diameter and 11 inches deep,
the top to be left open and wired with a heavy wire. Double seam a flat
bottom on this tank. Directly in the center of this bottom punch a hole
large enough to receive a 1-inch coupling. Then cut a 1-inch coupling in
half and solder it into this hole, putting the thread side down and
leaving it as near flush with the outside of the tank as possible, so
that if it is desired to move the air holder to and from a job it can be
taken apart and the lower tank nested in the upper tank, making a
compact bundle and reducing the danger of damage by careless handling.
To connect these tanks, all that is required is a piece of 1-inch iron
pipe, _h_, 12 inches long, with a coupling on one end. To operate this
air holder, close the two air cocks on the lower, or air, tank; then
fill the upper tank nearly full of water, taking care not to put too
much in it, or it will overflow the lower tank and get into the tubes,
and if this happens the tubes will have to be removed and hung up to
dry, or drops of water will be blown into the blow pipe and extinguish
the flame. It is then ready for use. The air in the air chamber is
compressed by the weight of the water in the upper tank, and if the
water line is at the same hight as the acid line in the hydrogen gas
generator the pressure of air must be the same as the pressure of gas.
As air is used the water descends through the pipe and will gradually
fill the lower chamber. It can then be forced back into the water
chamber by attaching the air pump to the cock _h_ in Fig. 9, or _d_ in
Fig. 10, without disturbing the gas or in any way interfering with the
operator. To connect with the cock _h_ in Fig. 9 it is only necessary to
disconnect one line of hose and connect the pump; then close the other
cock and work the pump until air bubbles up in the upper tank; then shut
the cock, remove the pump and connect the hose to the gasoline can, open
the cocks and the apparatus is ready for use.
Air Holder No. 2.
To make the air holder shown in Fig. 11, take a sheet of No. 26 gauge
galvanized iron 30 inches wide. Make it into a cylinder 26 inches in
diameter, double seam a flat bottom on it, and wire the top with ¼-inch
iron rod, which will make it stiff enough to withstand the pressure of
water. Close to the bottom and 3 inches apart punch two holes, _a_ and
_b_, large enough to receive ⅜-inch galvanized pipe couplings. Solder
these couplings in place.
On the inside of this tank and into these couplings screw two pieces of
⅜-inch pipe 4 inches long with elbows pointing straight up. Into these
elbows screw two pieces of ⅜-inch pipe long enough to come flush with
the top of the tank F. On the outside of the tank and into the ⅜-inch
couplings screw two ⅜-inch nipples 2 inches long, and on these nipples
screw two ⅜-inch hose end gas cocks.
[Illustration:
_Fig. 11.—Air Holder No. 2._
]
Now, with the same sized sheet iron, make another tank 2 inches smaller
in diameter than the first tank. This should have a flat bottom, and be
wired as previously described. Then take four strips of sheet iron 30
inches long and 2 inches wide, and form each into V shape lengthwise.
Lay off the circumference of this tank in four equal spaces. One side of
the V-shaped pieces should then be soldered on at each space. The other
side should be left loose to allow for adjustment. These pieces form the
guides to the upper tank and prevent it from tipping sideways and
binding. Two of the guides are shown in the illustration, Fig. 11.
The lower tank should now be filled about one-third full of water. The
upper tank should then be inverted and placed in it. The air pump must
then be connected to one of the ⅜-inch cocks with a short piece of hose,
and the air should be pumped into it until the upper tank rises to its
highest level.
The pressure in this form of air holder must be regulated by weights,
and to secure 1 pound of pressure it is necessary to place weights equal
to 1 pound for every inch in area contained in the opening in the upper
tank. Two drop handles, such as are used on heavy milk cans, should be
riveted and soldered on the sides of the tank to facilitate moving it
about.
Air Holder No. 3.
Fig. 12 is a cut of a bellows with a contained air holder. It is not
practical to try to make this article, as it can be purchased from any
plumbing supply house and is not expensive. It is used principally by
dentists, but it is also used in laboratories to supply air to the
compound blow pipe. It consists of a small bellows held from the floor
on iron legs, with a spring inside the bellows to hold them open, and
has a rubber bag fastened to the under side to hold a small supply of
air. The rubber bag is incased in a string net to prevent it from
becoming inflated too much and bursting. This bag serves to equalize the
pressure. The size known as No. 10 A will supply 75 cubic feet per hour
at a pressure of 1½ pounds to the square inch, which is sufficient for
lead as heavy as 24 pounds. For the light weight leads the pressure can
be reduced by pumping lightly and not filling the bag more than half
full.
[Illustration:
_Fig. 12.—Air Holder No. 3, Combined with Bellows._
]
Any of the three described air blast arrangements will answer the
purpose, so it is immaterial which is used, and it is left to the
discretion of the beginner to obtain whichever is the most convenient.
The Blow Pipe.
Next comes the blow pipe. The only practical compound blow pipe on the
market is shown in Fig. 13, and is known as Walmsley's. This is a
modification of the Bunsen burner, and consists of a bent blow pipe with
the air tube in the center, as shown in Fig. 14. It is a perfect working
blow pipe in every respect, and I should advise every one interested in
the work to purchase one. For while seams cannot be burned with it in
any other position than horizontal, it will be found useful in
lengthening traps or lead bends, for which purpose it is well adapted
and can be put into instant use, thereby saving its cost many times over
in wiping solders.
[Illustration:
_Fig. 13.—The Walmsley Compound Blow Pipe._
]
Burning with Illuminating Gas.
With illuminating gas it is only necessary to connect the gas jet to the
compound blow pipe with the hose and regulate the supply of gas with the
gas cock. The air inlet is then connected to the air holder, or air may
be supplied with the mouth, but good results are not obtained with the
mouth, as only a good blow pipe solderer can keep up the blast
necessary. To burn the seams use the same flux and follow directions
given for gasoline gas.
[Illustration:
_Fig. 14.—Sectional View of Walmsley's Blow Pipe._
]
Making the Gasoline Gas for Burning the Generator.
With a piece of ¼-inch hose connect the top of the can C, Fig. 9, with
the air holder D, then connect the spout or gas outlet _e_ of the can to
the gas end _f_ of the compound blow pipe. The air outlet _g_ of the
compound blow pipe should then be connected to the remaining cock _h_,
in the air holder. If the bellows is used, it will be necessary to
connect the air with ¼-inch tee, _m_, in which three short nipples have
previously been screwed.
The apparatus is now ready for use. Gasoline being really a liquid gas,
it takes its first opportunity to assume its natural shape. The natural
way to convert gasoline into gas is by simple evaporation. So taking
advantage of this fact, the action will be thus: By forcing air into and
through a body of gasoline sufficient of the gasoline is taken up to
form a dense vapor, which will light and burn at the jet, similar to
illuminating gas. With the admixture of air in the compound blow pipe,
it gives a flame of very intense heat. But, in common with illuminating
gas, it is so rich in carbon that it gives an oxidizing flame, and makes
it necessary to use a flux, which should be Yager's soldering salts
mixed as per the directions on the bottle. If this is difficult to
procure, a good substitute can be made by mixing equal parts of powdered
borax and sal ammoniac in a little water.
To operate this device the air should be turned on the gasoline and
lighted at the jet. The air should then be admitted gradually until the
flame is brought to the proper size and condition, indicated by its
being blue and pointed. If too much gas is admitted the flame will be
yellow and will blacken the work by depositing a coat of soot on it. If
too much air is admitted the flame will be ragged and noisy, and the
temperature will be too low to heat the metal. The flame is at its best
heat when it burns with a pale blue color which does not show any yellow
streaks.
Before attempting to burn the generator the beginner should practice on
pieces of sheet lead. It is next to impossible to burn seams in any
other position than horizontal with this flame, as it rapidly oxidizes
the lead, and in spite of all precaution the lead will become
unmanageable in upright seams, so that the beginner would waste time in
practicing on seams in any other position than horizontal. If directions
have been followed in cutting the lead for the generator the seams will
occur only in that position.
To burn the generator the seams should be shaved clean, both on the
under and upper sides, for a distance of ⅛ inch, making a seam ¼ inch
wide, taking care to have the lead seams lie close to each other, for,
if they do not, this flame will cause the edges of the lead to spread
away from each other and leave a hole that is difficult to patch.
Now apply the flux with a small brush. When the flame is in working
order bring it quickly to bear on the end of the seam nearest you to be
burned. When it starts to fuse draw the flame as quickly away, always
drawing it to one side, and from the upper to the lower sheet. The
melted drop will follow the flame and unite with the melted drop on the
lower sheet.
It is necessary to have the shave hook near at hand, so that, in case of
oxidizing when fusing, the melted drop can be broken up and allowed to
flow in place.
With a little practice and patience the generator can be burned all
right in this manner. This gas is perfectly safe and can be handled with
impunity. This method would, of course, be impracticable to use on a job
of any size, but I have used it several times where nothing else could
be obtained, and have always had very good success with it.
CHAPTER VI.
CONNECTING THE APPARATUS.
We now assume that the generator is charged and the rest of the
apparatus is finished and ready for use, so we will proceed to connect
it up ready for a trial.
About 30 feet of ¼-inch heavy rubber tubing should be procured. This
hose should be heavy enough to allow of its being pulled around without
kinking and shutting off the supply of gas. A piece of this hose 5 feet
long should be slipped on the gas cock M on the generator, shown in Fig.
1, and then slipped over the gas inlet tube of the scrubbing cup _n_.
One must be sure that this is connected to the gas inlet tube, which is
the tube that dips under the water in the scrubbing cup.
With another 5-foot piece of hose connect the gas outlet of scrubbing
cup _o_ to the right hand cock on the mixing fork _f_. Always connect
the gas on the same side so as to avoid confusion of cocks. Then with a
10-foot piece of hose connect the air cock on the air holder _p_ or
bellows to the remaining cock on the mixing fork _g_. An 8-foot piece
should be connected from the gas outlet on mixing fork _e_ to the blow
pipe _i_.
These tubes must fit tight to prevent any possible leak of gas, and if
they do not they should be tightened on with pieces of wire. The
remaining piece of hose can be used to connect the air pump C to the air
inlet cock _s_ on the air holder, but if the bellows are used this will
not be needed.
Now place in the scrubbing cup a half dozen pieces of blue vitriol, or
copperas, as it is commonly called. Then pour in clear water until it
flows out of the trap screw _z_. This screw can be made tight by using
for packing a piece of wicking which has been saturated with tallow.
After preparing the apparatus as above, refer to the cut of the complete
apparatus and compare the connections on the cut with those made from
the above directions, to make positive that they are right. If they
agree, the apparatus is now ready for use.
Testing the Apparatus.
It is necessary to test the generator for leaks, as a small blow hole
may sometimes be left in some of the seams or the cocks or cleaning
screws become defective.
To do this, first close the gas cock on the top of the gas chamber and
make up the cleaning and charging screws, which must be set on a bed of
soft putty. Then fill the acid chamber full of hot water, first
measuring the water so as to ascertain just how much solution is
required in proportion to the amount of water, as it takes the same
quantity at all times. Allow it to stand for a few moments, then mark
the water line with a pencil or nail, when it should be left standing
for an hour. The water should stay at the mark indicated for an
indefinite time. If it sinks during this test it shows that there is a
leak in the generator and it must be located and repaired.
[Illustration:
_Fig. 15.—Mixing Fork._
]
To locate the leak the gas cock should be opened and the water allowed
to run into the gas chamber. If this does not show the leak, force the
water back into the acid chamber, which is done by attaching the air
pump to the gas cock. Then taking a piece of soap and making a stiff
lather, daub it over the cocks and cleaning and charging screw. When the
leak is found the escaping air will cause bubbles to be blown. If the
leak does not become apparent after the above process, the side boards
of the generator should be taken off and the operation repeated on the
seams.
Under no circumstances must the apparatus be left until there is
absolutely no doubt as to its being perfectly tight, as a slight leak
would be likely to cause a disastrous explosion and injure or probably
blind the operator. Flying vitriol is not a very pleasant thing to get
in one's eyes.
The apparatus should be frequently tested in this manner: Before drawing
off the water it is desirable to learn what amount of gas pressure there
will be when the generator is charged, so that the pressure of air and
gas can be equalized. The mathematical rule for this is to multiply the
head in feet by 0.434, and the result will be the pressure in pounds; or
an approximate way of determining the pressure is to allow ½ pound
pressure for every foot of head. For example: The hight of liquid in the
generator measured from the bottom of the acid supply pipe to the top of
the water or acid line, when at its highest level, would be 3 feet.
Allowing ½ pound for every foot in hight would give a pressure of 1½
pounds, which is slightly in excess of the mathematical rule, which is 3
× 0.434 = 1.302, or 1 pound 4 ounces, but to be accurate it is well to
attach a mercury gauge to the gas cock. Note the hight of the column of
mercury. Then attach the gauge to the blast apparatus, and if the
floating air holder is used, sufficient weight must be put on the top of
air holder to raise the column of mercury to a point not quite as high
as is indicated by the generator. These weights can then be weighed and
a similar weight made of lead to correspond, which can be kept for
permanent use. If the bellows are used, the size specified should be
obtained, and the pressure will be all right for this size generator
without further trouble. If the air holder indicated by Fig. 8 is used,
all that is necessary is to make the hights of the water line in both
generator and air holder equal, and the pressure must be the same.
[Illustration]
_Fig. 16._ _Fig. 17._
_Mixing Forks._
The reason that the air pressure should not be heavier than the gas
pressure is that if the air were the stronger there would be danger of
the air working back into the gas tube and causing an explosion in the
tubes; consequently it is well to note this point carefully. Many lead
burners will say that the pressure of air is of no consequence, and all
that is required is a sufficient supply; but my experience and
experiments have convinced me that when the pressures of air and gas are
nearly equal the best results are obtained.
The Mixing Fork and Blow Pipe.
The mixing fork and blow pipe can be made in any plumbing shop and
should be made of the smallest size pipe available.
[Illustration:
_Fig. 18.—Blow Pipe and Tip._
]
To make the mixing fork, purchase two ⅛-inch female hose end gas cocks
and 2 feet of ⅛-inch iron pipe size brass tubing. Take a piece of the
tubing 12 inches long, cut a regular iron pipe thread on each end, then
bend it over a mandrel stake or a piece of 4-inch soil pipe into a half
circle, as shown in Fig. 15, so that the ends will come about 4 inches
apart. In the center of this piece drill a ⅛-inch hole, _a_. Then cut
from the remaining piece of tubing a piece 3 inches long. Solder, or,
better yet, have this piece brazed on to the bent piece at _a_, taking
care that no solder can run in and partially stop the hole _a_. Then
screw the two ⅛-inch gas cocks on the ends _b_ and _c_. This will
complete the mixing fork; or this fork can be made by bending a piece of
pipe at an angle, as shown in Fig. 16; then cut another piece equal in
length to the bent piece from the angle _e_ to the end. One end of this
piece must be filed to fit the piece _d_. A hole can then be drilled at
_e_. Threads must be cut on these ends, after which they can be brazed
together. Or a good fork can be had by using a special casting. This
casting is used for and is known as a beer switch, and can be purchased
of any dealer in bar supplies, Fig. 17. The same pattern and size of
cocks can be used for this fork as previously described. Neither of
these mixing forks has any advantage over the other, but three styles
are given, as possibly one may be easier to make than the other. Iron
pipe may be used instead of brass if desired.
To make the blow pipe, take the remaining piece of tubing and cut a
thread on one end. As the other end slips into the hose, it does not
need a thread. The thread end must then be bent at right angles to the
tubing, as _c_, Fig. 16. This can be done by boring a hole in a block of
hard wood just large enough for the tubing to enter, and 1½ inches deep.
Trim off the sharp edge of this hole so as not to kink the pipe in
bending. The end of the tube can then be inserted in this hole and bent
to the desired shape, as shown. This completes the blow pipes with the
exception of the tips, of which you should have three sizes, drilled as
follows: One for heavy lead, 3-32; one for medium weight, 2-32, and one
for very light sheets, 1-32. These tips are made of small pieces of cast
or turned brass, preferably with a milled shoulder, so as to facilitate
removing with the fingers. Probably the easiest way to get these tips is
to make a pattern out of wood and have several of them cast. They can
then be drilled and tapped to any desired size, or they can be cut from
a round bar of brass or copper, filed or turned to a point, then drilled
and tapped. The dimensions and particulars can be had from B in Fig. 18
without further description being necessary. A common blow pipe, such as
is used with the alcohol torch, can be used for practicing on light
sheets. But the beginner is advised to procure the blow pipe and a set
of tips described in Fig. 18 before attempting to burn any heavy lead.
CHAPTER VII.
CHARGING THE GENERATOR.
After making sure that the generator is perfectly tight we will proceed
to charge it. After removing the 4-inch charging screw take 15 pounds of
commercial spelter, which has been broken up with a hammer into pieces
about 2 inches square, and place this in the gas chamber, distributing
it as evenly as possible over the perforated bottom. This is done so
that the zinc will expose all the surface possible to the action of the
acid, and must be observed in order to obtain the best results. Do not
put any pieces of spelter into the generator that are small enough to
drop through the perforated bottom, for if they do they will be likely
to generate gas, which will give overpressure and blow gas out through
the acid chamber. This can do no harm unless close to a light, but it is
very annoying to have acid blown all over the generator. The charging
and cleaning screws must be screwed up tight. After closing the gas cock
on the generator take the quantity of water (less one-seventh) that was
found to be necessary when testing the apparatus, and pour this into the
acid chamber.
Mark the water line and watch it for a few moments to make sure that
everything is tight. Then take of sulphuric acid a quantity equal to
one-seventh of the water used, and pour that into the water in the acid
chamber. It will diffuse itself through the water and thoroughly mix.
Experience has taught me that acid mixed in any proportion stronger than
seven parts of water to one part of acid does not act as quickly as when
mixed in the proportion mentioned. The reason for this is that the
strong acid simply coats the zinc with a deposit or scum of sulphate of
zinc, which is soluble in water, but is not soluble in acid. Therefore,
if the acid is diluted with water to the above mentioned proportion the
water readily dissolves the sulphate and allows the acid to act freely
on the zinc.
This sulphate falls to the bottom of the gas chamber and if allowed to
accumulate causes the clogging mentioned later. The beginner will
observe from the explanation that the generator cannot be crowded by
making the solution strong. It sometimes occurs that the vitriol seems
to be stronger than usual, and then again the reverse is also true. Good
vitriol should be almost as thick as cutting oil, and will work very
quickly. Care must be taken in pouring it into the generator to prevent
spattering. This is best avoided by having a quart measure made of lead
for this purpose. It should also be borne in mind that the _acid should
always be added to the water_, never the water to the acid, as this
mixture always generates heat, and the result would be similar to adding
water to hot lead.
Automatic Action of the Generator.
The generator works best while hot. The gas cock on the generator should
now be opened and the mixture allowed to flow into the gas chamber until
it spurts out of the gas cock, which must then be closed. By this action
all the air in the gas chamber is expelled, leaving it free to generate
pure gas at once. This is a sure method of exhausting the air in the gas
chamber. The acid then attacks the zinc, causing it to decompose the
water and free the hydrogen contained in the acid.
This gas, by reason of its lightness, will rise to the surface of the
acid, and as pressure increases it will force the acid back up through
the acid supply pipe into the acid chamber, until the acid falls below
the perforated bottom. When the acid and zinc cease to come in contact
with each other the generation of gas stops until gas is used, which
relieves the pressure; then more acid descends, and as it comes in
contact with the zinc more gas is generated, replacing that which has
been used. This action makes the generator automatic, unless clogging
with sulphate of zinc takes place. This may happen at any time if the
apparatus is not cleaned after each day's use.
Cleaning the Generator.
To clean the generator in this case attach the air pump to the gas cock
on the generator and force the acid up into the acid chamber by pumping
air slowly into the gas chamber until the acid rises to the proper hight
in the acid chamber, where it can be held by forcing a long wooden plug
into the acid supply pipe. The pumping must cease when the acid rises to
the proper level, or the excess pressure of air will work up through the
supply pipe and cause a blow of acid.
The charging screw can then be removed and the zinc taken out and washed
in hot water. Remove the clean out screw and run one or two pails of hot
water through the gas chamber. This will remove the deposits of sulphate
paste. The zinc can then be replaced, the screws tightened and the acid
released again. Be sure and exhaust the air in the gas chamber, as
previously described, by letting the air spurt out of the gas cock
before connecting it to the scrubbing cup. Care must be taken not to
have any lights near the generator when blowing out this mixture of gas
and air, as it is very explosive.
The apparatus will never clog if cleaned after each day's work, which
should always be done. The tubes should be removed and hung up over
night to dry. The acid, if not spent, can be dipped out of the acid
chamber and placed in jugs. The generator can then be carried to a drain
and filled with hot water, which should be allowed to flow out through
the cleaning screw. This will clean the zinc and wash out all the
sulphate deposit. The screws may then be tightened and the apparatus
left ready for the next day's use.
Fire Trap and Scrubbing Cup.
One of the most essential parts of a lead burning apparatus is a
reliable fire trap and scrubbing cup. This trap reduces to a minimum the
danger from explosion caused by neglecting to free the gas from air. Its
use as a scrubbing cup is also of infinite value.
The action of the vitriol on the zinc produces a violent ebullition, and
a small quantity of the acid is carried in the form of spray from the
generator to the tubes, and, unless caught and removed, will frequently
get into the blow pipe tip and extinguish the flame, making it necessary
to remove the hose and hang it up to drain and dry, which oftentimes
causes waste of time and annoyance.
Almost all spelter or zinc contains more or less arsenic in a metallic
state. It is also found in sulphuric acid. This arsenic is released from
the acid or zinc as they decompose and is carried by the force of the
volume of gas to the blow pipe tip, where, owing to it being necessary
for the operator to get his eyes close to the flames in order to see the
reducing flame, this poisonous gas will be breathed into the lungs and
oftentimes cause a fatal illness. This fact has been disputed by many,
who say that it is impossible for the unit of lightness—_i. e._,
hydrogen gas—to pick up and carry a heavy metal such as arsenic. Arsenic
does not form a chemical combination with hydrogen, having a very slight
affinity for it, but is carried to the blow pipe solely by the force of
the volume of gas.
To prove the above assertion we will refer to Professor Marsh, who
demonstrated the ability of hydrogen to carry arsenic in the following
manner: If a solution containing arsenic be added to a solution of
sulphuric acid and zinc, the resulting hydrogen will, upon ignition,
deposit a ring of metallic arsenic upon any cold surface that the flame
be directed upon. (Professor Marsh's experiment.)
It will be seen from the above that it is imperative that the operator
use a scrubbing cup and see that it is properly filled with a solution
of blue vitriol. The ordinary impurities of hydrogen generated in this
manner are sulphur and carbon, which should be removed if possible.
The actual use of the scrubbing cup is to catch the above mentioned
spray and precipitate to some extent all other impurities contained in
the gas, and produce gas sufficiently pure for lead burning.
Directions for Making the Cup.
To make this cup take a piece of 4-inch lead pipe 7 inches long (an
ordinary piece of 4-inch lead soil pipe will do); flange out one end and
burn in a flat bottom. Three inches from the bottom, and in the side of
this 4-inch pipe, burn in a trap screw, _a_, Fig. 19, a screw taken from
an old lead trap being just the thing. This is to regulate the hight of
the solution in the cup. Now make a top by taking a piece of lead and
raising it about ¾ inch; punch two holes in this top, _b_ and _c_, large
enough to let a ⅜-inch lead pipe pass through; flange out the top of the
cup and fit and burn this top in place. Take two pieces of ⅜-inch lead
pipe, one to be 3 inches long and the other to be 10 inches long, and
with the dresser draw one end of each to nearly a point, so that the
hose can be slipped on tight. The long piece _c_ should now be slipped
through one of the holes in the top of the cup, holding it ½ inch from
the bottom _d_ and burning it in. This is the gas inlet and should be
marked as such. The short piece is then placed in the remaining hole and
burnt in place. The action will be thus: The gas entering the gas inlet
pipe is caused to pass through a solution of blue vitriol 2½ inches
deep, when the acid is caught and the gas is scrubbed and rendered as
nearly pure as possible. It then enters the outlet pipe and is ready for
use. If the directions have been followed the cup will resemble the
illustration Fig. 17. No trouble will be experienced with this cup.
[Illustration:
_Fig. 19.—Fire Trap and Scrubbing Cup._
]
CHAPTER VIII.
THE FLAME AND ITS MANAGEMENT.
Before attempting to light the gas the operator must be sure that all
the air is exhausted from the tubes. Otherwise the flame will go back
and explode in the tubes or fire trap. To be sure of this the beginner
must test the gas. A handy test tube can be made by capping one end of a
piece of ½-inch pipe, which should be about 6 inches long. To test the
gas, first open wide the gas cock M on the generator, Fig. 1. Then open
the gas cock _f_ on the mixing fork and let the gas displace the air in
the tubes, which it will do in about one minute. Then invert the test
tube, Fig. 20, and hold it over the blow pipe tip for a moment until the
gas has displaced the air in the tube. Then quickly place your thumb
over the opening of the test tube, which will keep the gas from
escaping. Close the gas cock _f_ on the mixing fork, then take the test
tube to one side away from the generator, still keeping it inverted, and
bring it close to a lighted match or candle. It will light with a pop,
and if it is free from air it will burn quietly down in the tube until
the gas is exhausted. Continue to test the gas in this manner until it
burns as described, when it may be safely lit at the jet without fear of
its burning back. This precaution is necessary only after opening the
generator for some purpose.
[Illustration:
_Fig. 20.—Method of Testing Gas._
]
Regulating Volume and Pressure.
This generator evolves gas under a greater pressure than can be used on
most work, and for this reason the flame will at first be long, noisy
and unsteady, as shown in A, Fig. 21, but, as there are two cocks, the
volume and pressure can be regulated to the requirements of the work at
hand. Now, to note the peculiarities of this flame, we will close the
gas cock _f_ on the mixing fork until the flame is about 3 inches long.
It will be of a pale reddish color and will burn steadily. The inner
flame is not as yet very well defined. Then open the air cock _g_
slowly, and when sufficient air has been admitted the flame will be seen
to shoot out suddenly and then shorten to about 1¾ or 2 inches in
length. It will be smooth, compact, and will have the appearance of
darting rapidly. If the correct quantity of air has been admitted the
inner flame, as shown in B, Fig. 21, will then be plainly seen, and its
apex, which is the point of greatest heat, will be blue. This inner
flame is known as the nonoxidizing flame, and is the flame with which
the fusing is done.
[Illustration:
_Fig. 21.—Flames Under Different Pressures._
]
The outer flame will change to a bluish color. Its temperature is low,
and its effect on the lead is to coat the metal with a heavy blue oxide,
under which the lead runs but does not unite. To demonstrate this, bring
the point of the inner or nonoxidizing flame to bear on a piece of sheet
lead. It will fuse bright and clean and will have a circle of gray oxide
around it. Then quickly remove the flame and the spot will remain
bright. Now, again bring the flame to bear on the same piece of lead,
keeping the point of the inner flame at least ¾ inch away from the lead.
It will melt and flow together, but will be covered with a coat of gray
oxide and the union will not be perfect. Slowly withdraw the flame, and
before the flame is entirely removed the spot will be heavily coated
with a thick blue oxide, under which the lead will not unite. C, in Fig.
21, shows the appearance of the flame when too much air has been
admitted and it is on the point of going out from lack of gas.
The proper way to use the gas is to open wide the gas cock M on the
generator, and do any regulating of the flame with the gas cock _f_ on
the mixing fork. These cocks should have pieces of heavy wire brazed or
soldered lengthwise of the handles, Fig. 16, _h_ and _i_, so as to form
lever handles. This will allow the gas and air cocks to be closed or
opened by gently tapping the levers _h_ and _i_, which is the only way
that a slight variation can be had, for if you try to regulate them with
the finger you will constantly open or close them too much, and the
result is that in adding air too much is always admitted, which will
blow out the flame, making it necessary to turn off the air and light
the jet again, and many times this operation will have to be repeated
before the flame is correctly adjusted.
It must be remembered to always turn on and light the gas before
admitting any air, and when through with the flame the air must be
turned off first, then the gas. If this operation is reversed an
explosive mixture of gas and air would form in the tube and would spoil
the tube, if nothing worse.
Study the Flame Well.
The beginner should study the flame until perfectly familiar with the
color and form of the proper flame. One of the greatest troubles that
the beginner will have with the blow pipe is the inability to regulate
the flame to the requirements of the work. For instance: A flame that
would work nicely on 12-pound sheets would burn holes in 4-pound sheets
before you had time to touch the lead with the inner flame. For that
reason three different sizes of tips should be used. On a 2-pound sheet
the smallest, or 1-32, tip should be used, and the flame before reducing
should not be longer than ¾ inch, and when reduced the inner flame can
hardly be distinguished, but you can easily tell when it touches the
lead by the metal fusing bright. If it is desired to fuse 12-pound
sheets the 2-32-inch tip should be substituted, and it would be found
necessary to have the jet of gas about 3 inches long, which, when
reduced, would be about 2 inches long and would show the inner flame
very distinctly.
The only way to determine the size of the flame necessary is by
experimenting with it. It will also come with experience. The flame
should be reduced to a size that will not melt the lead as soon as it
touches it. Rather, it should be in such condition that the lead would
have to be heated first and let the fusing come gradually. In that way
it can be determined just what sized drop is required, and also plenty
of time is allowed to place it just where it is wanted—particularly on
upright seams and _imperatively_ on inverted seams.
It is not necessary to be so particular on horizontal seams, as on seams
in that position you are assisted by gravity. The lead drop that is
melted from the upper lap cannot do otherwise than unite with the under
lap. It must be remembered that in starting a seam you have cold lead to
fuse, and after the first drop is started the lead in its vicinity will
be heated almost to the melting point, and you will probably be
surprised to see the lead run at the approach of the flame for the next
application.
Do Not Hurry.
The point to be taught here is that you must not attempt to hurry this
work or holes will surely be burned in the sheets, which oftentimes
makes difficult work to patch. The old adage, “haste makes waste,” can
well be applied to lead burning. Sufficient time must be allowed for one
drop to set before attempting to place the next drop. Time spent on
practicing at the bench is time well spent, as many little details that
cannot be brought to the beginner's attention here will be learned in
that way and stored in his mind for future application.
CHAPTER IX.
THE DIFFERENT KINDS OF SEAMS.
There are two kinds of seams proper, viz.: The butt seam and the lap
seam. The butt seam is used principally for joining horizontal waste
pipes and in lengthening traps, or for any purpose where it is desired
not to have the point of junction show. This form of seam can be burned
clear through—that is, the lead can be heated until fusion takes place
nearly through the entire sheet. It is generally necessary to add lead
to the seam if it is desired to make the seam as strong as the sheet it
joins, unless the article to be burned is of such a size as to be
possible to allow of its being burned on both sides, which makes the
strongest of seams. The lead for the butt seams is prepared by rasping
the edges of the lead sheet to be joined straight and true, Fig. 22, so
that when the edges of the lead are brought together they will fit close
its entire length. The edges are then shaved for a distance of ⅛ inch
each side of the edge, making a seam ¼ inch wide. On stock heavier than
12-pound sheets the edge should be shaved off, making a deep V-shaped
groove, and the seams must be made by adding lead. This allows the
fusion to take place nearly through the sheet. The butt seam is the
simplest form to burn, no matter in what position it is placed.
[Illustration:
_Fig. 22.—Rasping the Edges of the Lead Sheet Straight and True._
]
The lap seam is the seam commonly used, and as between the butt seam and
the lap seam the latter is generally to be preferred. As it is not
necessary to cut and trim the edges true, it dispenses with any
additions of lead, except at rare intervals; it leaves the left hand
free to handle the shave hook, and the lap can be dressed to fit any
uneven spots. It also makes the next best seam to through fusing. By lap
seaming a tank can be lined in about half the time required to butt seam
the same article, which is an important item to the customer.
[Illustration:
_Fig. 23.—Burning a Lap Seam._
]
The lead for this form of seam is prepared, as its name indicates, by
lapping one sheet ½ to ¾ inch over the other sheet. The under edges are
to be shaved clean, as also the upper edge. The lead required to make
the seam is melted from the upper lap and is fused on the lower sheet.
There is no reason why the lead at the point of juncture cannot be made
as thick as the original lead. This is the point aimed at in practicing,
and the only accurate way to determine the relative strength of the
seams is to cut squarely across a finished seam, then bend the beam
slightly. The thickness can then be noted. A cross section of a perfect
lap seam is shown at _a_ in Fig. 23. The beginner should practice the
different seams until the thickness of the joint can be told by the
looks of the lead. A few days' diligent practice at the bench will soon
train the eye to note any imperfection that may arise.
The different seams will be taken up serially. A description of how the
seams are prepared and the several positions of the blow pipe, as well
as the little difficulties that may arise, is the extent of the
instruction that can be given. The rest must come with practice and the
application of a little common sense. There is no royal road to this
business; but practice, and practice hard, is the only way to
satisfactorily master the blow pipe and flame, and in practicing
remember that all this work has been done before, and can be easily done
again, _and by you_. Do not get discouraged by failure to make a perfect
seam at the first application, but stick to it for a short time and it
will be found to be a most fascinating pastime, for which the persistent
student will eventually be well repaid.
Flat Butt Seam.
For practicing I would recommend the beginner to use pieces of sheet
lead about 12 inches long, as strips of that length are much easier to
prepare. The edges are straightened with a fine rasp which is held
lengthwise of and parallel to the edge to be trued, in the manner shown
in Fig. 22. The rasp must be used lightly, or it will be apt to tear the
lead and so leave it in worse condition than before using it. The edge
should then be gone over with the shave hook and cleaned. Then shave the
top surface a distance of ⅛ inch each way from the edge, which will make
a seam ¼ inch wide when finished. Then butt the edges together and
secure the sheets firmly to a board with a few tacks. The extra lead
that is necessary to add to make a butt joint full must be obtained from
a strip of lead, which should be about ⅛ inch square and _shaved clean_.
After regulating the flame to the proper size and shape the burning
should be begun at the end of the seam nearest the operator. With the
point of the inner flame melt off a drop from the lead strip and have it
fall squarely on the seam just slightly in advance of the point of
fusion. Follow it up with the flame, placing the point of the inner
flame directly over the edges of the seam, which is almost under the
lead drop. As soon as fusion commences on the lead seam the melted drop
will flow to the bright spot and immediately unite with it. The flame
must then be quickly removed and the drop be allowed to set.
In order to avoid any misunderstanding regarding the time required for
the lead drop to set I would say that the drop will cool immediately
upon the flame being removed from contact with it. It is not necessary
to wait for any specified time, but if the flame is allowed to play
constantly on the sheet it is apt to get overheated, and when in that
condition it takes very little heat to set the lead running like water.
To avoid this the flame should be lifted clear of the seam for an
instant after each drop has been fused into place.
[Illustration:
_Fig. 24.—Burning a Flat Butt Seam._
]
These remarks apply to all seams that are made by the blow pipe process
and should be noted, as this particular point will not be referred to
again. Now melt off another drop and let it fall as before, only it
should lap on the previous drop about one-half its diameter. Secure it
to the seam as before. This operation should be repeated until the seam
is completed, and if the seam is correctly done a section will appear as
_a_ in Fig. 24. This form of flat seam should be practiced until
perfectly familiar with the blow pipe flame and until the beginner can
approach the lead with the flame without burning holes through it, which
will probably be the first thing to happen.
Upright Butt Seam.
The upright butt seam is seldom used on large work, as it is a difficult
matter to make an upright butt seam that will stand the test, as, if a
finished seam is cut into short pieces, an examination of the severed
ends will show many weak places that were previously thought to be very
strong. The reason of this is that the heat necessary to fuse through
the lead will cause the lead to run from the seam and leave a hole.
The sheets for practice are prepared as described for flat butt seams,
and must be securely tacked to a board which can be supported in an
upright position. The burning is begun at the bottom of the seam. The
flame must be shortened considerably, as the fusing must take place
somewhat slower than in flat seams, as in upright or inverted seams the
attraction of gravity remains to be overcome, and the operator must have
plenty of time between the commencement of brightening and the actual
fusing to drive the melting drop to the exact position desired.
[Illustration:
_Fig. 25.—Burning an Upright Butt Seam._
]
The blow pipe is held so that the flame strikes the seam squarely and at
about a right angle with the sheet, as shown in Fig. 25. When fusion
starts the flame should be drawn quickly to one side, and if the lead is
at the proper temperature the melted drop will follow the point of
flame, and as it comes in contact with the adjoining edge it will
properly unite. It is not necessary to add lead to these seams oftener
than at intervals of 5 or 6 inches, or as often as the lead shows signs
of weakening, when it may be added by holding the lead strip against the
lead sheet and slightly above the flame. The melted drop will unite with
the sheet and can then be driven to any desired position. This seam will
show the characteristic beads, but they will lie nearly level with the
lead sheets, and if a scratch cloth be rubbed over the seam all traces
of the position of the seam will be removed.
To make a really strong seam it must be gone over with the flame at
least twice, as after fusion of the edges takes place the flame can be
used quite strong without fear of the lead running from the seam. Do not
leave this seam until you are satisfied that it is nearly perfect. It is
good practice, and every hour spent only makes the mastery of the next
seam come so much more quickly.
Horizontal Butt Seam.
This form of seam cannot be used to any advantage on general work, but,
like seams in other positions, it cannot always be avoided. The practice
sheets are prepared and tacked securely to the board, as previously
described, and are then placed in the position shown in Fig. 26. The
position of the blow pipe is as shown at _a_. The flame should strike
the sheet nearly square. The edge of the upper sheet should be heated
first, and as it brightens the flame should be directed onto the edge of
the lower sheet. If properly done, fusion will at once take place.
[Illustration:
_Fig. 26.—Burning a Horizontal Butt Seam._
]
The object sought is to get a light fusion between the two sheets before
attempting to burn the lead clear through the seam. If this is not done,
the lead will run from the upper sheet and cause holes, or at least will
seriously weaken the upper sheet, as shown in cross section at _b_.
After fusion is once obtained it is a simple matter to go over the seam
a second time, which can then be fused clear through without much danger
of burning holes through the sheet. Lead can be added in the same manner
as in upright seams if necessary.
Inverted Butt Seam.
This seam is used extensively in joining waste pipes which conduct the
acid from tanks to the drain. These pipes are usually in a horizontal
position and the seams must be burned in place. The most difficult part
of the seam is in starting it. When fusion has once taken place the
balance of the seam is easy. The seam is prepared the same as described
for other butt seams. Care must be taken to have the edges butt close.
The board can then be supported in the required position by any
convenient device.
The blow pipe flame must be made as short as possible and still melt the
lead. The point of the inner flame is then placed squarely on the seam.
Both edges must be heated at once. If the edges begin to brighten and do
not show an inclination to fuse, the flame should be drawn quickly to
one side, and the melted drop will follow the point of flame and unite
with the adjoining edge. This seam, in common with the other butt seams,
should be gone over the second time to assure a perfect seam. It is
difficult work to add lead to the flat inverted seam. When necessary to
do so, however, it can be added by burning the end of the lead strip to
the seam. The strip is then melted off, leaving a drop of lead affixed
to the seam, which can then be drawn to the required spot with the
flame.
The characteristic inverted seam shows pits upon examination of the
reverse side of the sheets. These are caused by overheating. The
operator will often be surprised at the inverted butt seam showing a
remarkable fullness. This is accounted for upon the examination above
referred to. The lead, upon the application of the heat, runs from the
upper or back side of the sheet and forms a very full seam. For that
reason the inverted butt seams always appear stronger than they really
are. See inverted lap seam, Fig. 27.
Lap Seams.
The lap seams are the seams commonly used on all classes of work. When
the beginner becomes proficient with the blow pipe no trouble will be
experienced in making lap seams that will show when cut a joint equal in
thickness to the sheets that are joined. The lead sheets for the flat
lap seam are prepared by shaving clean the exposed edge; also, shave the
sheets where they touch each other. The upper edges can then be shaved
for a distance of ⅛ inch each side of the lap, which will make the
finished seam ¾ inch wide, as shown at _a_ in Fig. 23. The sheets should
be lapped ½ to ¾ inch, according to the weight of the stock. It is very
evident that light weights would not require as large a lap as would
heavier sheets, as the object of lapping the sheets is to leave the
sheets practically as one piece, and the lead, to accomplish this
object, is to be melted from the upper sheet.
[Illustration:
_Fig. 27.—Burning an Inverted Lap Seam._
]
From the foregoing it will be seen why a 12-pound sheet requires a
½-inch lap, while a 24-pound sheet would require a ¾-inch lap. The
flame, when regulated to the work, is brought to bear squarely on the
edge of the upper sheet, slanting slightly in the direction of the lower
sheet, as shown. When the edge has brightened almost to the fusing point
the blow pipe should be drawn quickly to one side and from the upper
sheet to the lower sheet. If the metal is sufficiently hot the melted
drop will follow the point of the flame and instantly fuse with the
lower sheet, and if properly done the seam will resemble _b_ in Fig. 23.
This process is repeated, advancing about ⅛ to ¼ inch each time. Do not
attempt to fuse a large surface at a time. Experts cannot do such a
thing satisfactorily, so why should a beginner try to? Rather, try to
fuse small surfaces quickly and strongly, as better work and more of it
can be accomplished in that manner.
Horizontal Lap Seams.
This seam is prepared precisely as described for flat lap seams. The
strips can be fastened to a board with a few tacks. The strips can then
be supported in the position shown in Fig. 28. The burning is commenced,
as before, at the side nearest the operator. The flame must be made as
short as is consistent with the weight of the stock. It will be found to
the beginner's advantage to have fusion take place slowly. The point of
the inner flame is brought to bear on the outer edge of the lapped sheet
and at an angle of 45 degrees. Both sheets should begin to brighten at
about the same time. The melted drop must be driven against the back
sheet by the force of the jet of flame, and if the sheets are clean
fusion will take place quickly.
[Illustration:
_Fig. 28.—Burning a Horizontal Lap Seam._
]
The drops or beads of lead will appear very small on this form of seam,
owing to that great obstacle, gravity, which causes the drop when melted
to flow downward and so swell the seam. The drops, in common with other
forms of lap seams, should be made short, letting each drop overlap the
previous drop as much as possible. Great care must be taken not to
weaken the seam, as shown at _a_. The beginner should strive to get the
seams so that when cut into small sections each section will resemble
the result shown at _b_.
Upright Lap Seams.
Prepare the sheets as for flat lap seams, fastening the sheets securely
to a board, as previously described. The burning should be begun at the
lowest point of the seam. After regulating the flame, the point of the
inner flame is applied to the edge of the outer sheet slightly above the
point decided upon as the starting point, and at an angle of about 30
degrees, as shown at _a_ in Fig. 29. As the drop begins to melt it will
have a tendency to flow downward. By a quick turn of the wrist the flame
must then be directed against the back sheet and slightly under the
melting drop.
The under sheet should brighten at once, and the force of the flame,
being partially directed against the melted drop, tends to force it
against the bright spot on the back sheet, with which it instantly
unites. The flame must then be withdrawn for an instant, to give the
fused drop time to set. The operation must be repeated until the seam is
finished. Using ordinary language, it may be said that the drop is cut
from the upper sheet, carried slightly downward and then stuck against
the back sheet by the force of the flame.
[Illustration:
_Fig. 29.—Burning an Upright Lap Seam._
]
This seam is the one most used, and the beginner should practice it
diligently. After mastering it in the position shown in the cut, the
board should be fastened to the floor and the beginner should practice
burning the upright seam from above the work. This position occurs many
times in lining tanks, and the beginner who conquers the upright seam in
that position can consider himself sufficiently proficient to attend to
any job of lead burning that may arise. The beads of lead will appear
more compact and regular than in the flat seam, and if properly done
will upon cutting the sample show a very strong joint.
Inverted Lap Seam.
This seam should be attempted only after becoming very proficient with
the blow pipe and flame, after which it becomes as easy to burn as in
any other position. In order to get the range of the seam the sheets
should be arranged in the position shown in Fig. 27. The burning is
begun on the upright seam, and continued up and over the curved portion
and on to the inverted seam. The graduation from the upright seam to the
inverted seam is simple and gradual, and is hardly noticeable.
After accomplishing the inverted seam in this manner, strips of lead
should be prepared and fastened to the board as described for upright
seams. The board should be supported in an inverted position at a
convenient hight over the operator's head. The flame should be shortened
as much as possible. The burning may be started at any convenient point
and continue in each direction. The point of the inner flame is applied
to the seam at a slight angle, as _a_. The object is to obtain a fusion
between the back sheet and the upper edge of the lap. When this is
accomplished fusion proceeds easily.
[Illustration:
_Fig. 30.—Burning an Inverted Corner Seam._
]
The hardest part of this seam is in starting it, and when once started,
with a little patience and care, the balance of the seam can be fused
without any trouble. Fig. 30 shows an exercise which the beginner should
practice after having conquered Fig. 27, as it teaches the making of an
inverted corner seam. Of course, this position seldom occurs in small
work, but if the burning of it is once accomplished it will give the
operator considerable confidence in his own ability.
CHAPTER X.
PIPE SEAMS.
The Butt Seam on Round Pipe.
Pipes that are placed in a horizontal position are usually butt seamed,
as a stronger seam can be made in that manner. This form of seam is also
used in lengthening traps, bends, etc. To prepare a round pipe for butt
seaming, the ends of the pipe should first be made perfectly round by
inserting a drift plug and dressing the lead up close to it. The ends of
the pipe should be rasped true and then shaved clean. Also shave the
pipe for a distance of ⅛ inch each side of the edge. A piece of stiff
writing paper should then be rolled up the size of the pipe and inserted
in the ends. This paper will prevent any lead from running into the pipe
and leaving rough edges, as these afterward form an obstruction.
The burning should be commenced at the under side of the pipe, Fig. 31,
and proceed both ways from the starting point and finish at the top. If
the beginner has successfully overcome the difficulties of the seams
preceding this he will find no trouble in making a strong and
workmanlike seam on this pipe. Pipes are seldom used heavier than the
grade known as D for this class of work, and for that reason it is
seldom necessary to add lead to these seams. But if a hole should be
burned in the pipe on the under side, lead should be added to the top
side of the pipe and then made to follow the flame to the desired spot.
This will be found a quicker and more certain method than attempting to
add lead directly to the hole. A properly burned pipe should show the
full thickness of the pipe when cut with a saw.
[Illustration:
_Fig. 31.—Burning a Butt Seam on Round Pipe._
]
Through Seam on Round Pipe.
Where heavy pipe that is to be used under pressure is to be joined it
must be burned through to provide strength, and the ends prepared in the
same way as just described, but the ends must also be trimmed off all
the way around with a slight bevel reaching from the outside almost to
the inside bore of the pipe. The bevel must stop so as to allow a narrow
square butt end on each pipe. Then when a piece of paper has been placed
on the inside to prevent lead running into the pipe, the two ends when
butted will present a V-shaped groove, as shown in Fig. 32, reaching all
around the pipe. The burning is commenced at the bottom, as shown in
Fig. 31, and the two ends securely united. The groove is then filled by
burning on additional lead from a thin cleaned strip until the groove is
filled and the pipe made as heavy and strong at this point as anywhere
on its entire length.
[Illustration:
_Fig. 32.—Joint Prepared for Through Burning._
]
The Lap Seam on Round Pipe.
[Illustration:
_Fig. 33.—Preparing for a Lap Seam._
]
[Illustration:
_Fig. 34.—Burning a Lap Seam on Round Pipe._
]
This seam is used almost exclusively on pipe in a vertical position, and
is similar to the horizontal lap seam. The pipe is prepared by spreading
the lower piece of pipe with a drift plug one size larger than the size
of the pipe used. The end of the pipe intended to enter this socket is
rasped to a bevel edge, as shown at _a_, Fig. 33. This end is then
shaved clean, as is also the inside of the socket. The pipe is then
placed into the socket, which is then dressed up tight against the
inserted pipe, as shown in Fig. 34. The exposed edge is then cleaned and
burned, as described for horizontal lap seams.
The Tee Joint on Round Pipe.
[Illustration:
_Fig. 35.—Making a Tee Joint on Round Pipe._
]
With a pair of compasses set the diameter of the pipe that it is desired
to insert, and strike a circle on the pipe which is to receive the tee.
With a tap borer, or any other device, cut out a circle of lead, leaving
about ¼ inch to turn up. Then draw this remaining lead up by means of a
bending iron and a heavy piece of iron, such as a chisel, as shown at B
in Fig. 35, until the hole is large enough to receive the piece intended
for it, the end of which should be beveled with a fine rasp, as shown at
_a_. The lead should then be dressed back against the pipe, after which
remove the piece and shave clean, and proceed to burn as described for
the lap seam on round pipe, and as shown in Fig. 36. Care must be taken
in dressing up the lead flange to dress it slowly so as to avoid
weakening the lead.
Lining Tanks.
The lining of chemical tanks being the principal work of the chemical
plumber, a description of how this work is done will probably be of some
use to the beginner. In preparing lead sheets for a tank the sheets
should be cut so as to give the most seams on the bottom, because of the
greater ease in making them. In large tanks I find it convenient to put
the bottom in first, cutting it to make an easy fit, and then the sides
are put in. These are cut to allow ¾-inch lap on the bottom.
The lead sheets are laid on the floor, or some other smooth place, which
has previously been swept clean, and then dressed out smooth. This can
best be done by using the wooden dresser to take out the large wrinkles
and then smoothing with a lead flap. This flap is simply a piece of
sheet lead about 3 inches wide and 12 inches long, one end of which is
drawn into a roll to fit the hand. Then mark the laps and bend them to
the desired position. The under side of the lap should be shaved clean,
as also the lead under the lap, to facilitate fusion.
[Illustration:
_Fig. 36.—Burning in the Tee Joint._
]
If the tank is over 18 inches high the lead must be fastened to the
sides with bullseyes. These are made by countersinking places in the
sides of the tank. The lead is then dressed into these holes and it is
held in place with large headed brass screws, which are covered by
burning over the heads. Lead for the purpose is taken from lead strips.
The building up process is resorted to in covering these screw heads.
The lead should be arranged so as to avoid corner seams as much as
possible, as it is quite a difficult job to get the proper thickness of
lead in such seams. No rule can be given for cutting lead to fit a tank,
as tanks are of such a variety of sizes and shapes, and the lead is of
so many widths, that the mechanic must study how to cut the stock
without waste and have as few seams as possible.
CHAPTER XI.
ACID CHAMBER WORK.
It is not my intention to give an elaborate description of how acids are
made or to attempt to describe all of the different fittings employed in
that work, because while all plants are similar in construction no two
are alike. For that reason I will confine myself to the methods employed
in handling lead in large quantities, as the lead used in this work
ranges in weight from 18 to 24 pounds to the foot and is therefore very
heavy to handle. These chambers are known as condensing chambers, and
their use is to catch and condense a mixture of sulphur and steam which
is blown into them through a large lead pipe. For that reason they are
usually built out of doors, and sometimes have a sort of temporary roof
built over them. Consequently in repairing they are easily gotten at,
which, by the way, is seldom necessary.
[Illustration:
_Fig. 37.—Method of Framing Chamber._
]
To begin with, the sheet lead should be purchased of such a width as to
make as few seams as possible. The bottom of the chamber for this lead
to lie upon should be made of 2-inch cypress plank, the same to be
tongued and grooved as for floors, and should be planed down, if
necessary, so that it will present a perfectly smooth surface for the
lead to rest upon, for if there are any uneven spots that is where the
lead will eventually crack. The frame work for the sides should also be
put in place before the lead work is started, or at least enough of it
to prevent dirt and other stuff from bothering the burner. One end of
the chamber, however, should be left open, so as to enable the workmen
to bring in the lead or other material. The sides should not be closed
up, but should be framed, as shown in Fig. 37, so as to allow the lead
to be securely fastened to the frame work, which should be made of heavy
stock, depending, of course, upon the depth and size of chamber, as they
are in all sizes, from 10 feet to 60 feet long and longer.
After seeing that this part of the work is all right, begin to place the
bottom in position. This lead should be cut large enough to allow of its
being turned up about 2 inches all around for tight tanks. The sides are
not burned to the bottoms of some chambers, but the bottom lead is
turned up different hights, depending upon how deep it is required to
carry the acid in the chamber, which is from 4 to 10 inches or deeper.
The studding should be notched out to allow the turned up lead to face
with the face of the studding, otherwise there would be a bend in the
side lead where it overlaps the sides of the bottom. The flat seams in
the bottom should be butted together, so as to give a perfectly smooth
surface, which will allow all the acid to be drawn off.
[Illustration:
_Fig. 38.—Chipping Knife._
]
[Illustration:
_Fig. 39.—(A) Strap Split and Bent in Alternate Directions. (B) Bevel
End of Strap._
]
It is rather a difficult task for some men to cut heavy lead straight.
This is easily accomplished by first marking a chalk line on the lead
where it is desired to cut it off; then, taking the hammer and chipping
knife, as shown in Fig. 38, dip the blade of the knife in water, lay the
blade square on the line and strike the back of the blade lightly with
the hammer. Mark the sheet the whole length in this manner. Then go over
it again and repeat the operation, making sure that the knife is held
straight. The blade of the knife must be kept wet or it will stick in
the lead and cause it to glance off sideways. After it is cut any uneven
spots can be planed off smooth with a small smoothing plane, set so as
to take off a very light chip. The lead should now be placed in position
and dressed smoothly by using a piece of pine, or other soft board, as a
dresser. This must be laid on any uneven spots and then pounded down
smooth with a heavy wooden mallet, after which the seams should be
shaved and burned at once; or if the seams are short and it is desired
to put in enough work one day to keep the burner busy the next, strips
of paper 6 inches wide should be pasted over the seams to keep the dust
out. Only the edges of the paper should be pasted, so that when ready to
burn all that will be necessary is to take hold of one end of the paper
and strip it off, leaving the seam clean and free from dust and paste
and ready to shave and burn.
[Illustration:
_Fig. 40.—Roll of Lead in Position._
]
After the bottom is finished the sides must be put in, in such a manner
as to have as few seams in an upright position as possible, as it saves
considerable time to burn them when horizontal. On small chambers or
tanks not over 10 feet deep the carpenter should make a staging wide
enough to receive two sheets of lead and as long as the tank is deep.
The bottom of the chamber should then be covered with boards, so as to
prevent damage to the lead. The staging is then brought in and set up on
horses, and the sheets of lead are cut off and laid on the staging. The
seams are lapped, shaved and burned, after which the lead tacks or
straps are cut and burned on, to support the lead when in position.
There are different ways of putting on these straps. For side lead I use
strips of the lead itself about 3 inches wide and long enough to lap
well onto the studding. My way is to split this strip about ½ inch deep
and bend the ends in alternate directions. The edges are then cut off,
as shown at A, Fig. 39, after which they are burned in place. These
straps should be spaced not more than 15 inches apart, and should be
placed in such a manner as to come on the upper side of the studding.
[Illustration:
_Fig. 41.—Clamp and Method of Applying._
]
Another method of putting on these tacks, and one which is most commonly
practiced, is to trim the end of the strip of lead as shown at B, Fig.
39. The strip is laid flat on the lead sheet, with the bevel end down,
and is then burned onto the sheet in that position, after which it is
bent over the studding and nailed. The exponents of this method claim
that a better job is done in that manner, as there is always a lifting
pull on the strap. I claim for the first method that there is more
strength in the lead seam, and that as the edge of the studding comes
directly under the strap it acts as a sort of shelf for the strap and
thereby becomes a strong brace. But it is probably only a matter of
habit, as they hold all right either way.
Now, after having the seams burned and the straps in place, the lead
must be put in position. This can be accomplished by any arrangement of
block and tackles, but if the chamber be very large it will be found to
be a saving of time and labor to rig up a derrick. This is not such an
expensive thing to do, as a carpenter is always on hand and most likely
all the material needed is already on the ground. This derrick should be
constructed with a swinging boom, so that it can be raised, lowered or
swung into any desired position.
[Illustration:
_Fig. 42.—Showing Staging in Position._
]
Now to raise the side lead into position: The derrick is hooked onto the
hook or rope that is on the upper end of the staging. It can then be
easily raised in position. If the tank be very deep, or if it should be
too narrow to follow this method, the sheet lead should be rolled up on
a piece of 2, 3 or 4 inch iron pipe, depending upon the weight of the
lead. This pipe should be long enough to project at least 6 inches from
both ends of the roll. Two timbers, long enough to cross the frame work,
should be obtained. About 18 inches from one end of each timber a notch
should be cut to prevent the pipe from rolling. These timbers must now
be placed across the frame work just over the place that is intended for
the lead. The whole roll can now be raised with the derrick and the ends
of the pipe placed in the notches. The lead can then be pulled down,
similar to pulling down a window shade, after which the tacks can be
burned on in place. This is shown at _a_, Fig. 40. Or if there be room
enough the piece of lead can be cut from the roll, dressed smooth and
have the tacks burned on while on the floor. The upper end of the lead
can then be rolled over and nailed to a piece of timber 2 × 6 inches or
heavier, and the derrick hooked onto this and raised in position. This
is the easiest method where there is room to do it. These are a few of
the methods used, but there are numerous other ways.
To place the top lead in position requires a staging, which can be built
as follows: Enough hooks should be made to properly support the staging,
shown at A, Fig. 41. Two timbers should be laid across the top of the
chamber, far enough apart to allow two strips of lead to be placed in
position at once. The hooks are now hooked over these timbers, while two
pieces of 3 × 3 or 4 × 4 are placed in the other end of the hook. Planks
are now laid over these timbers and the screws set up until the tops of
the planks come just level with the top of the lead—not higher, or else
they will prevent the joist from being placed in position.
The lead can now be cut off on the ground and hoisted up to the top,
where it becomes an easy matter to place it in position. The lead tacks
can now also be cut and burned on. They should be cut sufficiently long
to allow them to lap over the top of the joist, as shown at _a_, Fig.
42, where they should be nailed with large headed nails. It will be
noticed that the tacks are doubled up on the top lead and that they are
not set opposite each other. The joist can now be set and the tacks
nailed on, after which ropes can be tied onto the projecting ends of the
4 × 4 timbers and the whole staging be lowered to the floor at once.
This operation can be repeated until the whole top is on.
[Illustration:
_Fig. 43.—Lead Headed Nail._
]
It will be necessary to leave small holes between the lead seams at
intervals for the hooks to pass through. However, these can be burned
over at any time, and where the ends of the top should overlap the end
of the chamber the lead can be left turned up until the staging is
removed, after which it can be turned over and burned. The hooks are
made of ⅝ round iron and have a long thread cut on one end, so as to
allow for adjustment. The details are shown in Fig. 41. There are also
numerous fittings used in connection with these condensing chambers, but
they are all easily made and are too simple to take up space here in
explanation. Should it be necessary to use nails for any purpose on the
inside of the chamber, the heads should be dipped into a pot of melted
lead that has not quite set until the adhering ball of lead is about ½
inch in diameter, as shown in Fig. 43. These nails can be driven in
place and the lead burned to the sheet lead, which will prevent
corrosion.
CHAPTER XII.
SPECIAL HYDROGEN APPARATUS AND BURNER.
The articles on the universal method of lead burning having been
completed, I desire to call attention to a new method and a new
generator recently patented and put on the market by the Kirkwood & Herr
Hydrogen Machine Company, 3129 South State street, Chicago, Ill. It is
called the Kirkwood generator and a general view of it is given in Fig.
44. This generator is a radical departure from the old style generator,
as used for the purpose of lead burning, inasmuch as it dispenses with
the air blast and consequently with the mixing fork and tubes. The air
required to reduce the hydrogen gas to a working condition is obtained
by absorbing the air at the mouth of the burner.
The new generator differs also in the amount of pressure used on the
gas. With the old style generator, previously described, a pressure of
1½ to 2 pounds is used, whereas the Kirkwood generator is used under a
pressure varying from 8 to 30 pounds. At the higher pressure the maker
claims the best results are obtained. The generator is made in a size
that enables the operator to take it to a job on a street car or train,
and that while containing the full charge of acid and zinc, as it weighs
when charged about 50 pounds. This is a very important advantage over
the old style machine.
Construction of the Generator.
The generator is constructed, so to speak, just the reverse of the old
style generator, inasmuch as the lower chamber contains the charge of
acid, while the zinc is placed in the upper chamber. The generator shown
in the sectional view, Fig. 45, is cylindrical in shape, 9 inches in
diameter and 30 inches high. A horizontal partition, to which is burned
a pipe long enough to reach to a point about 1 inch above the bottom of
the acid chamber, is burned into the cylinder at a point a little above
the middle of the cylinder, making the acid chamber larger than the gas
chamber. This arrangement allows the back pressure of gas to force the
acid down into the acid chamber, compressing the air in the acid chamber
without permitting any gas to find its way into the acid chamber and
thus preventing a waste of gas. In this horizontal partition and over
the pendent pipe a number of ¼-inch holes are drilled or punched. This
enables the acid to pass freely into the gas chamber, and prevents any
small particles of zinc from falling into the acid chamber, which would
generate gas in the chamber. Connected to the top of this acid chamber
is a small pipe which runs up through the gas chamber and terminates
above it, as shown. This pipe has an air inlet valve, or small hose end
gas cock, connected into the side of the pipe, to which the hose from
the force pump is attached when supplying air to the acid chamber to
force from the acid chamber to the gas chamber in order to start the
generation of gas. A safety or blow off valve is also attached to this
pipe at the top, and is set to an ordinary working pressure of 15
pounds, or to any pressure desired. If gas is being generated faster
than is required it gets up a pressure in excess of 15 pounds. Then the
safety valve opens and allows the air in the acid chamber to escape
until the gas goes down to the desired pressure again. This obviously
allows a portion of the acid to return to the acid chamber, and later,
as the acid becomes weaker, the air in this chamber will have to be
renewed by the admission of a little more air.
[Illustration]
_Fig. 44.—General View._ _Fig. 45.—Sectional View._
_The Kirkwood Lead Burning Machine._
[Illustration:
_Fig. 46.—The Kirkwood Lead Burner._
]
A large charging screw is placed directly in the top of the gas chamber.
Into this is screwed a tee and short nipple, or it may be a special
fitting made for that purpose. On this tee or special fitting a pressure
gauge is screwed, and a float valve is attached on the branch. Into the
gas chamber or as close to the partition as possible an angle valve is
placed.
To Operate.
To charge the apparatus the safety valve is removed and the amount of
the charge of acidulated water having been previously ascertained, the
charge is poured into the acid chamber through the air pipe. The charge
of spelter or zinc is placed in the gas chamber through the charging
screw on top of the gas chamber. The pump is now attached to the air
inlet cock with a short hose, and a few strokes of the pump will force
the acid up into the gas chamber until the zinc is completely submerged.
The generation of gas will begin at once.
The cock on the burner is then closed until the necessary working
pressure is obtained, when it is ready for use. The pressure of gas can
be regulated by setting the safety valve to blow off at a greater or
less pressure, as desired. The use of the float valve is to prevent acid
from being forced out of the gas chamber and into the tube. If this
happens, the valve floats up and instantly closes the outlet, in which
condition the valve remains until sufficient gas is generated to force
the acid back into the acid chamber. When first charging the machine,
acid should be forced up into the gas chamber until this valve closes,
as that will force all of the air contained in the gas chamber out
through the tube, leaving only pure gas in the generator. When the acid
is spent it is easily removed from the generator by attaching the pump
to the air inlet cock and forcing the acid up into the gas chamber. The
angle valve is then opened, when the spent acid can be drawn off into a
pail or other receptacle. This will not drain the acid chamber
absolutely dry, but practically so.
When the operator ceases work, as for dinner or for any purpose, all
that is necessary is to open the air inlet cock and detach the hose from
the gas outlet. The acid will return by gravity to the acid chamber when
generation ceases. When the operator is ready to resume work a few
strokes of the pump will start generation again.
The Burner.
The burner, shown in Fig. 46, which is the most important part of the
apparatus, is also constructed on a principle not heretofore used on a
lead burning apparatus. It consists of a small tube, to one end of which
is screwed a small cock, similar to a pet cock. To the other end, at a
convenient angle, is brazed the burner proper. This consists of a needle
point valve. The needle point, being about ½ inch long, is arranged so
that the point can pass through the gas outlet about 1-16 inch. This
seems to spread the flame in such a manner that it absorbs sufficient
air to reduce the flame. It can be regulated by drawing the needle in or
out, as the work requires. There is also a tube arranged to act as a
by-pass or subflame. By opening the valve on this by-pass a pilot or
subflame is maintained, which does away with the annoyance of having the
flame pop out or become extinguished, as it is instantly ignited again
by the subflame. In operating, the flame is held at such a distance from
the work as experience will teach to be proper, or until the lead starts
to melt. It should fuse with that well-known and instantly recognized
bright appearance which indicates the nonoxidizing flame.
Any one who is used to handling the blow pipe can easily familiarize
himself with this blow pipe. The maker claims that 2 quarts of vitriol
will serve to operate the apparatus for a day of 8 hours on lead as
heavy as 12-pound. I have no doubt that it will do even more than the
makers claim for it. The apparatus is made in three sizes, adapted for
different classes of work. After the experience I have had with it, I
feel sure that any beginner can use this apparatus safely if he uses
ordinary judgment and care in handling a gas apparatus that needs common
sense treatment.
CHAPTER XIII.
SOFT SOLDERING WITH THE MOUTH BLOW PIPE.
The common blow pipe is a simple little tool that is used in connection
with an alcohol torch for soldering the finest and most delicate pieces
of jewelry, and constitutes the sole method of soldering used by
Britannia workers and jewelers, and the fact that such a varied
assortment of articles are soldered by the blow pipe process leads one
to surmise that it can be used to advantage on coarser work. Though it
is a familiar tool to gas fitters, plumbers as a rule are ignorant of
its use, and it is hard work to find one who ever saw a blow pipe used
on lead work. It is an easy matter to become proficient in its use, and
the trick of keeping up a steady blast, and breathing regularly at the
same time, is soon learned, and, when once acquired, stays with you
always. This trick consists of making a bellows of your cheeks and using
your tongue as a valve to close the entrance to the throat, leaving the
passage from the nostrils to the lungs clear for breathing purposes. The
only things necessary to purchase for practice are a common bent blow
pipe, which can be had for about 15 cents, and a common candle.
[Illustration:
_Fig. 47.—Position of Candle and Blow Pipe._
]
To operate: The candle should be lighted, and when it burns well and
freely the tip of the blow pipe should be brought close to the flame and
slightly above the wick, _a_, Fig. 45. Then blow lightly through the
blow pipe, and a pointed clear blue flame from 1 to 2 inches long, which
will burn paper or char wood at a distance of 6 or 8 inches from the
flame, will be the result. The flame is hottest and best when it shows a
perfect cone-shaped blaze, and is obtained by a very moderate blast. The
variation of the blaze can be noted by commencing to blow very lightly
and increasing the pressure gradually. The flame will then show all
stages from a smoky flame to a long blaze that cannot be concentrated on
any small surface. The little sharp tip is where the hydrogen burns, and
is the hottest part of the flame, being the part that is used for
soldering.
Now, having noted these peculiarities, and knowing the perfect flame by
sight, we will proceed to acquire the steady blast. The blow pipe should
be held between the lips, which will form a tight packing around it, and
must not come in contact with the teeth. The cheeks are then inflated,
which will have a tendency to throw the tongue back to the throat and
prevent the air in the mouth from blowing out through the nose. Now, by
contracting the cheeks, and throwing the tongue slowly forward, the air
will be forced through the blow pipe. This action is assisted when
exhaling air by the pressure of the lungs, but when inhaling air the
muscular contraction of the cheeks is depended upon entirely for the
blast.
The ability to keep up a steady blast is merely a trick, or knack, and
is learned with a few hours' practice; when learned, the length of time
that the blast can be kept up depends solely upon the strength of the
muscles of the cheeks of the operator. If these did not tire, the blast
could be kept up for an indefinite time. Having learned to keep up the
steady blast and get a perfect flame, the beginner will want to practice
soldering. The blow pipe method of soldering has for its range of work
everything that can be soldered, from Britannia metal to platinum, but
the only metals that are used by the plumbers are tin and lead and their
several compositions, so we will confine ourselves to the study of those
metals.
Kinds of Solder Used.
In soldering any metal the solder should be so proportioned that it will
melt many degrees lower in temperature than the metal to be soldered.
Otherwise it would be quite probable that holes would be burned in the
work before the solder would melt. There are exceptions to this rule,
however; for example, lead burning, where one piece of lead is fused to
another. As also with Britannia metal, it can be, and is, soldered with
its own material, but it would be likely to have holes burned in it
occasionally, and to avoid this a solder mixed for that purpose should
be prepared. Two receipts are given here for quick melting solders that
are suitable for this work. The first is preferred, but the second will
answer the purpose.
Solder No. 1: Procure 4 ounces of pure lead, 4 ounces of pure tin, and 2
ounces of bismuth. The lead should be melted first and thoroughly
stirred and cleaned. It should then be allowed to cool to the melting
temperature of the tin, which should then be added. Lastly add the
bismuth. The whole should then be stirred and poured into a suitable
mold into very thin strips, about the size of a No. 8 wire, making
strips of solder that can be rolled up and carried in the pocket.
Solder No. 2: This solder is composed of two parts of tin and one part
of lead. These should be mixed as described above. To have success in
making solders several points must be observed. The metal melting at the
highest temperature should be melted first, which must then be allowed
to drop to the melting temperature of the next metal to be added, and
when ready to pour into molds the mixture must be stirred, as the
specific gravity of the several metals differs considerably, and unless
constant stirring is resorted to the mixture will partially separate
upon cooling, and the result is an irregular solder that will not do the
work.
Practicing the Blowing.
Now, for practice, take two pieces of ¼-inch lead tubing and prepare
them as for a cup joint, by spreading one end with the bending iron and
rasping the other end to fit the cup, as shown in _a_, Fig. 33. Support
them as you best can in an upright position. Flux the joint with rosin.
Then take the solder in the left hand, set the lighted candle at the
right hight and distance from the joint, as shown at B, Fig. 47, which
leaves the right hand free to manage the blow pipe. Then heat the joint
with the flame, and, as it gets hot, touch the joint with the solder,
and when it reaches the melting temperature of the solder a drop of it
will detach itself and flow clear around the joint, making a smooth,
clean joint that is stronger than the pipe itself.
Joints made in this manner present a handsome and workmanlike appearance
to the mechanical eye. Practice diligently on the lead pipe until you
have become so proficient that you can flow the solder all through the
joint without withdrawing the flame. Then procure some ⅜-inch block tin
pipe, and, when that can be soldered perfectly, the beginner can
consider himself sufficiently proficient to practice on flat seams on
Britannia metal.
Soldering Britannia Metal.
For working Britannia metal the candle cannot be used, as the dripping
grease will cover the work and seriously interfere with the flowing
solder. The beginner must provide himself with an alcohol or kerosene
torch. A good form of torch, manufactured and sold for electricians'
use, is shown in Fig. 48. The alcohol gives a clean flame, but by
comparison is somewhat expensive. The kerosene gives a flame that can be
concentrated on a small surface with fully as much heat, and if care is
taken to allow only the blue flame to touch the work, it is fully as
clean and cheaper.
[Illustration:
_Fig. 48.—Alcohol or Kerosene Torch._
]
[Illustration:
_Fig. 49.—A Specially Constructed Torch._
]
The burning kerosene torch gives off a dirty smell and smoke, which
makes it disagreeable to handle, but this is a case of take your choice,
and it is left to the beginner to use either, as they will both do the
work satisfactorily. It is also necessary, in doing this work, to have
the blow pipe attached to the torch and connected to the mouth with a
piece of very small rubber tube. This will leave one hand free to apply
the flux and hold the solder. The flame can also be quickly placed in
any position or directed to any portion of the work without allowing the
work to cool. The alcohol torch for this work should be so constructed
that it can be held in a horizontal or inverted position without
spilling the contents of the torch.
The handiest, as also the cheapest, torch to make is the one shown in
Fig. 49. It consists of a can 3 inches high made in the shape of a
frustum of a scalene cone. The tube B should be ¼ inch in diameter, and
must run parallel with the flaring side and extend half way to the
bottom of the can, as _e_. Then, when the torch is tipped to solder
horizontal work, the alcohol will flow into the space _a_, leaving the
alcohol to supply the wick to be drawn up by capillary attraction. This
tube is made of ¼-inch brass tubing, bent to form an angle with the can,
as shown.
[Illustration:
_Fig. 50.—Using the Torch on a Flat Seam._
]
A screw and cap with a seat, such as is used on brass lamps, is
obtained, and a hole punched in the cap _c_ just large enough to receive
the tube B. The screw is soldered into the opening of the can at D. The
wick, which is formed of many strands of candle wicking rolled tightly
together, is pulled through the tube by means of a wire hook, and left
sufficiently long to lie in the space _a_, so that it will always lie in
the alcohol. This tube is placed through the hole at D, and allowed to
project about ¾ inch outside of the can. Wicking is then wound around
the tube and forced into the socket formed in the screw D. The cap is
then slipped over the tube at _c_, and screwed down tight on the
wicking, which will make a tight joint at D, and will hold the tube
firmly in place.
When necessary to fill the torch the tube can easily be removed and the
torch filled. A separate filling screw can be used if desired. Even with
this form of torch an excess of alcohol will occasionally get into the
wick when used in a horizontal position and increase the size of the
blaze. But when this happens the torch can be brought to an upright
position for a moment, which will drain the wick and bring the blaze to
its proper size.
The blow pipe for this torch is made from a piece of very small copper
or brass tubing. The end intended for the tip should be bent to the
angle required, as shown at _f_, Fig. 49. It should be fastened to the
torch by means of a clamp, _g_, soldered to the flaring side of the
torch. This clamp should be so arranged that the blow pipe can be
adjusted to the requirements of the blaze. This clamp consists of a
short piece of brass. A hole is drilled in one end to allow the blow
pipe to pass through, while the other end is filed to fit the bevel of
the can to which it is soldered. The blow pipe can be held in position
with a wedge, or a hole can be drilled and tapped and a small screw
inserted which will hold the blow pipe firmly in place. The tip of the
blow pipe should not be larger than 1-32 inch. The rubber tube can then
be attached to the projecting end of the blow pipe at _h_, which is then
ready for use.
[Illustration:
_Fig. 51.—Cutting Metal for a Butler's Pantry Sink._
]
Owing to the Britannia metal melting at such a low temperature, it would
be well for the beginner to practice on pieces of 2-pound sheet lead.
Seams on this class of work are made by butting the edges of the metal,
as these seams are not supposed to show. The seams are prepared by
truing the edges and then beveling the edges with the shave hook so that
when brought together a V-shaped groove is formed. This is then fluxed
with a small amount of powdered rosin. A drop of the quick melting
solder is then melted from the strip and allowed to drop on the seam.
The flame is then applied to the sheets, and as the solder flows the
flame must be kept slightly in advance of it, Fig. 50. Care must be
taken to heat the sheets only enough to cause the solder to flow.
Otherwise the seam will not appear full. The beginner should experience
no trouble in soldering these lead seams, and when perfect control of
the torch and flame is had, pieces of Britannia metal should be
substituted for the lead. These seams are prepared and fluxed just as
for lead.
Britannia metal is fast becoming the favorite lining for splash and drip
boards on butler's pantry sinks, as also for lining the work benches in
saloons. It is soft enough to allow the most delicate china to be laid
on it without danger of chipping, and is also very easy to keep clean.
It takes a high polish and always looks well. The method of cutting the
metal for a butler's pantry sink is shown in Fig. 51, the dotted lines
showing the actual dimensions of the article to be covered, while the
full lines show the laps required to cover the edges of the board. This
metal is harder than lead, and will not dress smooth with the dresser.
Any uneven spots must be pressed down with a hot flatiron. The method of
turning the edges is shown at _a_. The bending iron is heated and rubbed
over the edge, gradually turning the edges until they are at their
proper position. The iron must be constantly heated to insure the best
results, and if properly done no wrinkles will appear. A lined work
bench is also shown in Fig. 52, which shows the method of putting in the
bar washer. The sheet metal must be cut and fitted to its place and all
the seams possible should be soldered before placing the metal in
position. The edges should be tacked on the under side of the work, when
practicable, with copper tacks.
[Illustration:
_Fig. 52.—A Lined Work Bench, with Bar Washer._
]
Sooner or later the blow pipe solderer will be called upon to make
repairs on Britannia metal, and will be surprised to find that it will
be impossible to solder the metal, owing to the excess of moisture under
it. The best way to overcome this, which is practically the only trouble
that occurs, is to cut out a small square patch. The edge can be cleaned
and a patch of new metal carefully fitted into the hole. When ready to
begin soldering, a piece of blotting paper should be inserted between
the patch and board. This paper will absorb all the moisture and allow
the seam to be neatly soldered. The man who makes himself familiar with
the blow pipe and torch soon finds himself in a different class from the
ordinary everyday mechanic, and if mechanical ability be accompanied
with sobriety and stability, the possessor will always command a good
steady income.
THE END.
INDEX.
Acid Chamber, Framing, 109
Acid Chamber Work, 108
Acid, How Applied, 66
Acids, 20
Action of Generator, 66
Addition of Acid, 66
Air and Gas, Regulating Volume and Pressure, 74
Air Holder, 40
Air Pressure, 58
Alcohol Torch and Blow Pipe, 133
Apparatus for Lead Burning, 15
Arsenic, Poisonous Flame, 69
Arsenic Released from Acid on Zinc, 69
Bellows Air Holder, 49
Blow Pipe, 50, 62
Blow Pipe, Kirkwood, 122
Blow Pipe, Mouth, 127
Blow Pipe Practice with Candle, 128
Blow Pipe, Walmsley Compound, 50
Blue Vitriol or Copperas, 56
Bottom for Generator, 35
Britannia Metal for Repairing, 140
Britannia Metal Soft Soldering, 132
Britannia Metal Work, 14, 31, 32
Britannia Metal Work with Torch and Blow Pipe, 132
Burner, Kirkwood Lead, 119
Burner Tips, 62
Burns and Their Treatment, 17
Candle Blow Pipe Practice, 128
Care of Apparatus, 68
Cautions, 16
Charging and Cleaning Screws, 26
Charging Generator, 64
Chemical Tanks, How Lined, 105
Chipping Knife for Lead, 110
Cleaning Generator, 67
Colors of Flame, 76
Connecting Apparatus, 55
Cup, Scrubbing, 56, 68
Cup, Scrubbing, How Made, 70
Cutting Heavy Lead Straight, 110
Explosions, What to Do When They Occur, 17
Fire Trap, 56, 68
Flame Management, 73
Flame Under Different Pressures, 74
Flat Butt Seam, 83
Framing Acid Chamber, 109
Gas from Gasoline, How Generated, 39, 51
Gas Pressure, 58
Gasometer Air Holder, 46
Generator, Charging, 64
Generator, Cleaning, 67
Generator Construction, 26
Generator Frame, 30
Generator Materials, 30
Generator Pipe, How Fitted, 37
Generator Seams, How Burned, 36
Horizontal Butt Seam, 88
Horizontal Lap Seam, 93
Hydrogen and Air, Effect of Mixing, 24
Hydrogen Apparatus, Special, 119
Hydrogen from Water, How Made, 25
Hydrogen Gas and Its Properties, 18
Hydrogen Gas, How Made, 20
Hydrogen Proved Lighter Than Air, 23
Illuminating Gas Burning, 51
Inverted Butt Seam, 90
Inverted Corner Seam, 98
Inverted Lap Seam, 92
Joint for Through Burning, 102
Kirkwood Blow Pipe, 122
Kirkwood Lead Burner, 119
Knife for Cutting Lead, 110
Lap Seam, 82
Lead Burning Explained, 10
Lead Headed Nail, 117
Lead Sheets for Tank, 105
Lining Chemical Tanks, 105
Mixing Fork, 55, 57, 59
Mouth Blow Pipe, 127
Nail, Lead Headed, 117
Pipe Seams, 100
Pressure for Working Gas and Air, 58
Repairing with Britannia Metal, 140
Round Pipe Butt Seam, 100
Round Pipe Lap Seam, 103
Round Pipe, Tee Joint, 104
Scrubbing Cup, 56, 68
Scrubbing Cup, How Made, 70
Seam, Butt, on Round Pipe, 100
Seam, Flat Butt, 83
Seam, Horizontal Butt, 88
Seam, Horizontal Lap, 93
Seam, Inverted Butt, 90
Seam, Inverted Corner, 98
Seam, Inverted Lap, 92
Seam, Lap, 82
Seam, Lap, on Round Pipe, 103
Seam, Through, on Round Pipe, 101
Seam, Upright Lap, 95
Seam, Upright Butt, 86
Seams, Different Kinds of, 80
Seams, How Prepared, 80
Seams, Pipe, 100
Sink, Bar and Washer, 138
Sink, Butlers' Pantry, 137
Soft Solder, 13, 130
Soft Solder Formulæ, 131
Solder, Soft, 13, 130
Special Hydrogen Apparatus, 119
Staging for Acid Tank, 115
Straps for Tank Lining, 111
Tanks, How Made, 12
Tee Joint on Round Pipe, 104
Test for Hydrogen, 21
Testing Apparatus, 56
Through Burning, Joint, 102
Through Seam on Round Pipe, 101
Tips, Burner, 62
Tips, Sizes of, 78
Torch, Alcohol and Blow Pipe, 133
Trap, Fire, 56, 68
Upright Butt Seam, 86
Upright Lap Seam, 95
Vitriol, 56
Vitriol Action on Zinc, 69
Walmsley Compound Blow Pipe, 50
Water Pressure Air Holder, 42
TRANSCRIBER'S NOTES
1. Silently corrected typographical errors.
2. Retained anachronistic and non-standard spellings as printed.
3. Enclosed italics font in _underscores_.
*** End of this LibraryBlog Digital Book "The Art of Lead Burning - A practical treatise explaining the apparatus and processes." ***
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