A soldering gun is a tool used for soldering projects. A soldering gun is source of heat which is a main requirement for melting solder during soldering operation. It has a pistol shape with trigger style switch. This trigger must be depressed to begin the heating of soldering gun. Soldering guns come in a variety of sizes.
Carl E. Weller invented soldering gun in 1941. Soldering irons of the time needed long worm up time. Too much time was wasted waiting for soldering iron to heat up. The reason the soldering iron took so long to heat up was that the wires in a soldering iron needed to heat up first, before the heat could even reach the tip of the iron. Carl Weller wanted to design tool which requires short worm up time and the result of that design was a soldering gun.
A soldering gun consists of a transformer which converts 110 AC to a lower voltage. A secondary of transformer has only one turn. This way the secondary of transformer produces very low voltage (below 1V) and several hundred amperes of current. That voltage is routed through the copper soldering tip, which is heated by the high current flowing through it.
Soldering gun and soldering iron perform the same function however there are many differences between these two soldering tools. A soldering iron uses fine windings of resistance wire to generate heat while soldering gun uses transformer with a single-turn secondary element.
Recently, soldering irons have improved worm up time and matched the soldering guns in terms of how fast they heat up. However, soldering guns won’t be replaced any time soon because of the fact that they can be quickly and easily turned on and off.