Soldering is the process in which two metals are joined together by means of a third metal or alloy having
a relatively low melting point. Soft soldering is characterized by the value of the melting point of the third
metal or alloy, which is below 450°C. The third metal or alloy used in the process is called solder.

In a soldering process, heat is applied to the parts to be joined, causing the solder to melt and be drawn
into the joint by capillary action and to bond to the materials to be joined by wetting action. After the metal
cools, the resulting joints are not as strong as the base metal, but have adequate strength, electrical
conductivity, and water-tightness for many uses. Soldering is an ancient technique that has been used
practically as long as humans have been making items out of metal.