Soldering Electrical Joints

Abstract

AN article in the Electrical Review of August 28 describes the technique and selection of suitable materials. The process of soldering may be defined as the uniting of metals by means of an alloy melting at a lower temperature than their fusing points, as distinct from welding in a state of fusion. The solder alloys with the surface layers of the parts to be joined and the process is not simply one of adhesion. There are two broad classes of soldering, namely, soft soldering in which tin-lead alloys are mainly used and hard soldering in which alloys of copper-zinc (brazing) or of silver-copper-zinc (silver soldering) are employed. Soft soldering is used very extensively in electrical work and silver soldering to some considerable extent; brazing is rarely used. The electrical conductivity of soft and hard solders is considerably less than that of copper, varying with composition between approximately 9 percent and 13 percent for soft solders and 20 percent and 40 percent for silver solders.