Solder and Soldering Iron

Brazing and welding have sometimes been described as specialized forms of soldering. These two techniques also involve the joining of two metals with each other, but each differs from soldering in some important ways. Probably the single most important difference is the temperature range at which each takes place. While most forms of soldering occur at temperatures in the range from 356°F (180°C) to 590°F (310°C), brazing usually takes place in the range from 1,022°F (550°C) to 2,012°F (1,100°C), and welding in the range from 1,832°F (1,000°C) to 6,332°F (3,500°C).

The first step in both brazing and welding is to clean the two surfaces to be joined. In brazing, a filler is then inserted into the gap between the two surfaces and heat is added, either at the same time or immediately after the filler has been put into place. The filler then fuses to form a strong bond between each of the two surfaces. The filler used in brazing is similar to solder and performs the same function, but it melts at a higher temperature than does solder.

During the welding process, a thin stick of filler is added to the gap between the two surfaces to be joined the same time, a hot flame is applied to the gap. The filler melts, as do the surfaces of both metals being joined to each other. In this case, the two metal surfaces are actually joined together and not just to the filler itself, as is the case with soldering and brazing.

Most alloys used for brazing contain copper and zinc, often with one or more other metals. The term brazing itself, in fact, derives from the fact that copper and zinc are also the major components of the alloy known as brass.