Welding guns are used in MIG welding (welding which uses Metal Inert Gas) with MIG welding wire which is typically fed through the hand held welding gun to form an arc with the welding piece. As an electrode, the MIG wire melts to a molten state and is deposited into the weld joint where it cools to form the bond, or weld. MIG welding is also referred to as Gas Metal Arc Welding (GMAW).