Naw you can weld thin metal with arc. It is not easy. You have to use small diameter rods, low amps and know what you are doing. To high amps + thin metal = blow hole. I was a professional welder for years welding tig, mig and arc. Hands down I would use mig. Not saying you can't blow a hole with mig but if he was welding on my rig he would use mig.