Repair work is done generally in either a job welding shop, where a number of welders are employed and where all kinds of welding is carried on, or else in a garage or automobile repair shop where a welder is employed to do the necessary work. In small communities the welding shop is usually run by one man who owns it and who does all the welding. In the large welding shops acetylene is generated; in other cases dissolved acetylene is used. A welder who is expert in the welding of aluminum is particularly valuable in this work.
In manufacture, the work is done in the shop. It is often simple and well suited to workers who must elect a sedentary employment. The process is broadening its scope in this field.
Closely related to the automobile is the motorcycle. A number of its parts, such as handlebars, special jigs and muffler heads, are welded in manufacture. In repair work the scope is somewhat similar to that of automobile repairing.
PLAN No. 1144. PIPE AND MAIN WORK
In the welding of pipes and mains, the process is finding increased application and this field presents good prospects of expansion in the future. Extensive work in this country as well as in Europe, where it is more largely used, has demonstrated that welding is not only the most economical method but as well the most efficient in that leaky joints are eliminated. Welding does away with threaded joints, and thus makes possible the use of much lighter pipe, since there is no need for making allowance in thickness for threading. Moreover, joint couplings are dispensed with. The expense saved in maintenance alone is tremendous, as the joint is water-tight and there is therefore little likelihood of trouble arising from leaks. In making connections, Y’s, T’s, crosses and drips are made on the spot, being cut out of odd lengths of pipe and fitted together. This effects an economy in that these odd pieces are saved.
The process has its greatest application in the welding of gas, steam, air, oil, water and ammonia pipes and mains, and the work is chiefly outside work, although it is used to some extent on interior pipe connections. Special fittings or connections may be welded in the shop. Outdoors welding is generally performed on sections of pipe while above the ground, the whole section being finally lowered into the ditch. The welding of these several sections to each other has to be done in the ditch or trench, a pit being generally dug in order to give the welder sufficient room for carrying on the work. Obviously this work requires suppleness in the worker.
Where there is a large amount of welding, the apparatus most commonly used is a portable generator, with which is mounted a set of oxygen tanks. In other cases a small two-wheeled truck carrying one oxygen and one dissolved acetylene cylinder may suffice.
In this kind of work, the welder is generally assisted by one or two helpers who do the heavy work, placing, holding, and turning the pipes while the welder keeps on welding. Some overhead welding is done which forces the welder to assume a strained position.
PLAN No. 1145. SHEET METAL
Welding sheet metal is an important application of the process, which is superseding to a large extent riveting and soldering. Very careful work may be required but in the main the work is not particularly difficult, and it can be easily mastered if the training given is thorough. Electric resistance welding, however, is superseding oxy-acetylene in many manufacturing operations.