As we explained in the previous section, the solder added into the bonding process can be made from a wide-range of different metal alloys. The metal alloy must be relatively soft to make it easy to melt, and also have enough fluidity to be evenly distributed throughout the joint area to create a solid bonding base. The joint must be able to resist corrosion, according to the conditions in which it will be exposed.
The type of metal alloy to be used for soldering, will depend on the working temperature, and the types of metal it is bonding together. The interaction between the solder and the materials must not result in the strength of the joint being diminished. Theses days solder can be bought in the form of bars, pastes or spools of wire.
In the following table, we present the most common types of metal solder alloys and their uses: