Due to the high heat conductivity of aluminum alloy, the heat generated from the electric current and contact resistance dissipates quickly. This makes spot welding unsuitable for repair of aluminum panels. To spot-weld aluminum alloy, an extremely strong current of well over ten thousand amperes is required. For that reason, ‘‘MIG welding” must be used to weld an aluminum alloy automobile body.

MIG welding is a gas metal arc welding (GMAW) method where an electric arc forms between the consumable welding wire and the work piece, which heats and melts the wire and work piece, welding them together. During welding, inert argon shielding gas is supplied from a gas cylinder protect the welding area from atmospheric gases such as nitrogen and oxygen. The welding wire is automatically fed at a constant sped, based on the welder settings.