Soldering, Brazing, and Welding #221326

Apart from the use of rivets, screws, etc., metal is commonly joined by soldering, brazing, or welding, three groups of processes that have one thing in com mon — the use of heat to fuse either the metals them selves or an alloy which is interposed to consolidate the joint. The word solder is derived through the French from a Latin word meaning solid. Soldering may be soft or hard. Soft-solder ing uses lead-tin alloys which are easily melted in a bunsen gas flame or with a hot iron or bit; while hard soldering employs a silver-copper alloy, to melt which a mouth blowpipe at least is necessary. Brazing is hard-soldering with spelter (brass), and a forge or a heavy blowlamp or a powerful blowpipe must be employed to provide the heat.