Differences of Metals Used in Solder

General Purpose

• Also called "half and half solder," plumber's solder is comprised of half lead and half tin. This solder is a general purpose solder and is the most commonly used variety of solder. It has good process characteristics --- strength, non-brittle --- making it suitable for most jobs and it is the best studied and understood solder available. Tin-antimony-lead solder has better mechanical properties than tin-lead as a general solder, but cannot be used with zinc.

High Temperature

• Several alloys are suited to soldering at high temperatures, but each has its distinctive characteristics. Cadmium-silver has good tensile strength but is a toxic solder. Lead-silver has good fatigue strength with low to medium flow properties. Tin-antimony is non-toxic, used in food production and has superior electrical conductivity. Tin-silver is expensive solder used in manufacturing medical and high precision instruments, also non-toxic.

Low Temperature

• Solders appropriate for use under low temperatures include bismuth and indium. They have more than low temperature application in common, but are still unique. Bismuth is a solder that deforms very easily and requires aggressive fluxes --- liquid cleansers that prevent oxidation --- for good bonding. Indium also deforms quickly but aggressive fluxes are not required.

Solders for Aluminum

• Solders appropriate specifically for the soldering of aluminum pieces include cadmium-zinc, tin-zinc and zinc-aluminum. Cadmium-zinc is a toxic solder alloy. Tin-zinc and zinc-aluminum are two alloys that are non-toxic and of equal characteristics when soldering aluminum metal pieces. A higher functioning solder among these three has not been established.