since you are an instructor, I have a question. I happen to already have a Carbon Dioxide tank with the regulator, left over from a Pizza Shop and soda pop use. How compatible is CO2 for use with welding and is it a good substitute for Argon. I would like a Mig for occasional use on auto body panels and a Tig would be nice too, but awful expensive for just making small parts like mufflers. I am thinking now only about a Mig system and have looked at the Harbor Freight systema also. (Is Chicago Electric their house brand?) This is more that one question now, maybe we can bring this thread to life again. We have a Harbor Freight in our area now and I am wondering who is buying their welding machines? I don't know anyone that has one to give an opinion, does anyone know someone with one? The people at Harbor Freight only know about selling and that is why I didn't jump at their prices which look pretty good at first glance, but what about service as brought up previously in the thread.