Solder

Solder, a fusible alloy used for joining metals. For some of these there are two classes of solders, called hard and soft. Under the head BRAZING the composition of hard solders for brass and copper is given. Common brass makes a solder for iron. 'Silver solders,' which melt at a lower temperature than ordinary hard solders, are used for brass, copper, and sometimes even for iron. One kind is composed of equal parts of silver and brass; another variety consists of these two metals and zinc in equal proportions. These solders are a little costly, but when they can be used they give much satisfaction. The solder used by silversmiths is usually made of two of silver and one of brass. Goldsmith's solder varies with the fineness of gold to be joined, the coarsest kind being formed of three of gold, two of silver, and nearly two of copper; but the proportion of gold is much higher for fine work. Soft solders for brass consist of two of tin and one of antimony, and of lead and tin in equal or nearly equal proportions. The latter is also used for lead, but plumbers use besides a mixture of one of tin to two of lead. For pewter a little bismuth is added to these two metals. A solder of two of tin and one of lead does for zinc. Suitable solders for the above metals can be purchased already prepared. The fluxes usually employed are borax or sal ammoniac for hard solders, and resin, muriatic acid, or Baker's mixture for soft solders.