SHOP EQUIPMENT
(=41=) In equipping a shop for welding, in addition to the welding
apparatus, the operators are many times undecided whether it is
advisable to have a planed metal or a brick top table to use for
welding purposes; each has its advantages, but were there a choice of
one or the other, it is suggested that the brick-top table be used. The
theory of having a planed metal top for lining up work does not prove
as satisfactory in actual practice as might be expected, for the simple
reason that the average welder generally places his metal in direct
contact with this cold top, and much of the heat which is supposed to
go into the weld is conducted away by the table top, producing a hard,
brittle weld. In the case of cast iron, these welds are generally
porous. Then too, the operator to a large extent depends upon the table
top for lining up his work and does not study his contraction and
expansion as thoroughly as he might. The result is that many of his
pieces warp in cooling. To rectify the first objection it is advisable
to cover the table top with asbestos paper as shown in Fig. 28. In the
second place, sometimes clamps are used to hold the work in position.
Preheating without a layer of bricks on a metal-topped table is not to
be recommended.
[Illustration: FIG. 28.--Method of Holding Heat when Welding on Metal
Top Tables.
Asbestos paper, _P_, is laid upon the metal top, _M_, and the pieces,
_A_ and _B_, placed upon _P_ in such a manner that the weld can be made
at _C_. The asbestos paper prevents too much heat escaping from the
bottom of the weld.]
[Illustration: FIG. 29.--A Fire-brick Table for Welding.
Angle iron measuring 2 by 2 by ¹⁄₄ inches is welded together in the
manner shown and covered with fire-bricks which measure 2¹⁄₂ by 4¹⁄₄ by
9 inches.]
(=42=) A fire-brick table, made up along the lines shown in Fig. 29, is
very easily constructed and can be used for all sorts of jobs. It is
well to have everything clear around the legs and have no braces to cut
the operator on the shins or to interfere in any way with his work.
The best fire bricks obtainable should be used. A large number of extra
bricks should always be on hand for they come in very handy in most of
the welding operations, and in fact to conduct a welding shop without
fire bricks could almost be likened to a blacksmith’s shop without an
anvil. Besides being used for table tops, preheating furnaces of a
temporary nature may be built and the bricks used to jack up and align
many jobs which could not be handled otherwise.
(=43=) An emery wheel plays a very important part in a commercial
welding shop, insomuch that rust, scale, and unnecessary metal can be
removed in a very short time by its use. A flexible shaft attachment
should be on hand, if possible, or a portable grinder of some kind,
for in many cases where the casting, or the piece being worked upon is
too heavy to bring to the emery wheel, the wheel can be brought to it
and many places ground down by its use that would be impossible with a
stationary grinder.
[Illustration: FIG. 30.--One Shop in which Instruction in Steel is
being Given, at the Ordnance Welding School.
Note the construction of the welding tables. Two or more may be placed
together, to give as large a surface as desired.]
(=44=) Many times when working near a hole which may be threaded, the
welder has much difficulty in keeping his metal from entering the
hole. At other times it is necessary to back up preheated work such
as aluminum, to prevent its collapsing. Ordinary clay or putty cannot
be used for this purpose. The simple reason being that when metal is
heated it expands and the clay or putty in giving off its moisture
contracts, showing two opposite reactions. Retort cement is a name
given furnace cement mixed with shredded asbestos, this, as well as
carbon flour, has been found to be very satisfactory for filling in
holes and backing up pre-heated work. Retort cement is purchased in
airtight containers, hardening very quickly when brought in contact
with the air, so at all times it should be kept in containers similar
to those in which it is purchased. It cannot be reclaimed once it is
hardened.
(=45=) A blacksmith forge will be the medium of saving much valuable
gas and time in a welding shop. It will heat up parts to be welded in
very short order and while in this condition they may be welded and
then thrown back into the forge and allowed to cool very slowly.
(=46=) Several pails of water should always be located where welding is
being done to prevent fire from flying sparks; to cool the torch tips
and filler-rods, when working on large jobs; to keep certain parts of
work being welded cool, and to harden or temper other parts.
(=47=) A simple and efficient manner of handling flux in the welding
shop has puzzled many welders, on account of the flux containers being
easily upset, their inaccessibility and the action of the air upon
large quantities of flux. A simple method of overcoming this is to cut
in two, a two and one-half or three-inch pipe coupling and mount it by
welding on a square piece of one-eighth inch plate, as shown in Fig.
31. This type of container is very hard to upset; may be used when
working on preheated jobs; is easy to get at on account of its shallow
nature, and, as it only holds a small amount of flux, it can be
cleaned out frequently and a fresh flux will always be available.
[Illustration: FIG. 31.--A Good Flux Container for the Welding Table.]
(=48=) Additional equipment beneficial to the welder will be a quantity
of various sized carbon rods and blocks; asbestos paper; goggles;
V-blocks for lining up shafts and an assortment of mechanics’ tools,
such as wrenches, hammers, chisels, hack-saws, and other things which
might be used in dissembling or assembling various kinds of machinery.
(=49=) Another important item which is generally overlooked in the
average welding shop is the question of ventilation. Although the
welding flame itself contains no objectionable gases, those from fresh
charcoal preheating fires, those given off when some of the alloys
of the filler-rods are melted when brass, copper, and other metals
are being worked on, and from gas engine exhausts are not desirable.
At times they will give the operators violent headaches unless means
are taken to carry them off. The ventilation should be such that it
will not directly affect the work. Drafts are to be avoided as much
as possible, for many times they will warp pieces being preheated
if allowed to come in direct contact with them. It is a good thing
to remember that indirect ventilation and plenty of it is a prime
requisite in a good welding shop.