YK So you want to get techincal huh. There is no such thing as mig anymore at all smart ass. DO you know who you are talking to? Im a welder by trade with a college degree. MIG stands for metal inert gas. Gmaw usings 75-25 or c02 in most cases. Guess what c02 is not inert it reacts with the metal. FCAW is gasless and it can use gas too. Its called dualshielding. I have certs in gmaw, fcaw (dualshield) stick welding, submerged arc welding, in fracture critical welds for bridges. For flat, horizontal, vertical and overhead. The term mig welding is by ppl who dont have a clue about welding. Its used as a term for wire feed welding.