TIG stands for "Tungsten Inert Gas"- - - - -it just heats the metal with an arc from a tungsten electrode with an inert gas shield to prevent oxidation. Fill rod is added from a separate source like with oxyacetylene welding. MIG- - - -"Metal Inert Gas"- - - -wire is fed through the stinger and deposits itself automatically. TIG is cleaner and more controllable than MIG because the puddle can be manipulated without adding a constant flow of filler. Both systems have their purpose, as well as heavy duty high amperage work on thick metal with a conventional stick welder.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!