Piston soldering

In piston soldering, an electric heating element in the metal shaft of the soldering iron generates the required heat. The shaft is a heat accumulator and conducts the heat to the soldering tip, which heats the solder joint.
Because of its high heat capacity, copper is the most commonly used base material for the shaft and soldering tip. To prevent scaling, the soldering tip is coated with a nickel or iron layer. An extension of the soldering iron are specially shaped heating plungers, which are adapted with their contour for the soldering point.