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Hand Forging by Thomas F. Googerty
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BRAZING 75
Brazing.—Two or more pieces of iron or steel may be fastened together by brazing them with spelter. Spelter is a mixture of about one part of copper and two parts of zinc. The more copper is added and the less zinc, the more heat is required to melt it, and the stronger the spelter will be.
Brass may be brazed by using spelter, but requires more care in heating. In this case the spelter should contain more zinc than is in the mixture of brass, so that when heated the spelter will flow before the brass is melted.
Copper may also be brazed with spelter. This metal is much easier to braze than brass, as it will stand a much higher heat before melting.
In brazing iron or steel, brass wire or sheet brass may be used if desired. The pieces to be brazed should be fitted to a reasonably close joint, and the joints or laps should be dressed with a file in order to have them clean and free from any foreign matter. The pieces must be fastened together so that they are firm while brazing. This may be done by riveting, or binding them with wire. When fastened they are placed in a clean fire—one with a well burned bed of coke. Fresh coal must not be placed on the fire while brazing. The pieces may be heated with a very little blast until a red heat is reached; then it is shut off. A flux, such as borax, is now placed on the joint,
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Hand Forging by Thomas F. Googerty