Argon welding is a popular name among people for welding technology, in which welding is performed in a shielding gas environment, most often argon. The gas prevents the metal under welding from coming into contact with the oxygen in the air, preventing oxidation. Inert argon is well suited for this purpose as it is non-toxic and relatively inexpensive. The equipment for argon welding comes in two types, TIG and MIG. In both cases, the machines are equipped with a non-consumable tungsten electrode. The difference is that TIG uses separate hard facing rods, but in MIG, the wire is fed automatically from the spool, for which people often call this method semi-automatic.