This is a subsidiary work in large building plants. It consists of making tanks, casings, large copper pipes, fenders, wheel guards, smoke and other conduits, and receptacles for oils and other materials. The heavier sheet-metal work is done in the boiler shop, where it is shaped by the equipment of that shop. The lighter sheet-metal work is shaped by hand appliances in the copper shop or sometimes in a separate sheet-metal shop.

Sheet metals are fastened together by riveting, soldering, or brazing. Seams in wrought iron or mild steel sheet work of moderate thickness may be readily and effectively welded by the oxy-acetylene blowpipe. Wiping a joint in plumbing work and sweat-ing-on are forms of soldering.

By far the greater part of sheet-metal work is done in re-manufacturing processes such as were described in Chapter V (Mechanical Treatment Of Metals. Heat Treatment Of Metals. 142. Forms Of Newly Produced Metals). In plants which do this kind of work, large quantities of a particular article are made at minimum expense, and only special articles of certain shapes needed in small quantities are shaped by the expensive manual operations of the sheet-metal shop in a general building plant.