Ok thank you very much! I am kinda clueless on metal thickness, but whatever sheet metal is on old lawn tractors is, thats what its going to be used for. I would like to stay with either a lincoln or miller unit, as i have been told they are top of the line.Basicly I have 800 bucks to spend and really want to get the most bang for my buck, which seems to be the lincoln 140. Then again with the autoset, the miller sounds promising to. The diffrence in cost is about 120 bucks which i am willing to spend if that is the best route to go. Thanks again