Like no parent has a favorite child, no welder will tell you MIG welding is better than TIG—or vice versa. Both processes are similar. They both use an electric arc that heats metal to form the weld. They can both join a wide variety of metals. And they both use a shielding gas to protect the weld from atmospheric impurities. But each performs certain things better than the other.
Tungsten Inert Gas (TIG) welding utilizes a non-consumable electrode to deliver an electrical current to the welding arc. The resulting heat melts the metal being welded into a puddle. The tungsten electrode and puddle receive protection from weld-ruining atmospheric menaces via an inert gas, typically argon. In most cases, a hand-held filler rod strengthens and reinforces the weld. However, some thinner materials don’t require a filler metal and may be fused.
Metal Inert Gas (MIG) welding utilizes a spooled wire electrode to feed electricity into the work and melt the base metal. The MIG electrode also acts as a filler metal, strengthening the weld. The electrode feeds out of the welding machine at a rate predetermined by the operator. The wire feed speed and voltage are adjustable to obtain the desired weld. They are customized according to different materials and thicknesses.