soldering

[SOLDER, ข.] The proce of uniting two pieces of the same or of different metals by the interposition of a metal or alloy, which, by fusion, combines with each. In autogenous soldering, the two pieces are directly united by the partial fusion of their contiguous surfaces. In the ordinary proce of soldering small articles, the workman places the two metallic surfaces together, and then, with his soldering iron, which has been previously heated in a furnace, melts off sufficient solder from the stick or cake, allowing it to flow on and between the parts to be joined; the hot iron is then applied to the joint, so as to cause the solder to become uniformly fluid, equalize its distribution, and smooth its exposed surface. The surfaces to be joined must be perfectly cleaned by filing or scraping, and the flow of the melted solder is also a isted by the employment of certain substances as either deoxidizers or fluxes; among these, resin, sal-ammoniac, or muriatic acid are chiefly used. Instead of a soldering-iron, some form of blow-pipe is often employed to heat the solder. Another method sometimes employed to solder small bra articles is to face and clean the two surfaces, rub them with sal-ammoniac or dilute acid, and then squeeze them into contact with a piece of tinfoil between them. When the whole is heated, the two are soldered together by the melted tinfoil.