Solder is used to join electrically conducting parts. The parts are first mechanically secured and then quickly heated with a soldering iron. The solder is applied to the heated mating surfaces and is allowed to melt and whet the surfaces. The soldering iron is then removed from the joint. The finished solder joint metallurgically bonds the parts and forms highly conducting electrical connection and a strong mechanical joint between the metal parts. Examples of metal parts that require soldering are transistor/IC leads and PCB track, wire and connector, or resistor/capacitor and tag board.