I had a Miller tig unit and sold it cuz it was just too damn difficult.(I wanted to put my car together not learn another vocation) I went back to my mig unit with .030 wire and used stargon gas with it and it worked great. Those copper backer bars help but can be a pain to get a good contact with the panels.Also like someone earlier said get a 220v unit if possible if not get the highest amp 110v unit