Well, I bought some 0.023 wire and it does help a little. Maybe 10% less power. I think the bottom line is butt joints on sheet metal are just plain tough to do well. Especially with a home welding machine. I fixed some rust pits in the inner to outer cowl panel on my truck and just used a shaped copper backing plate (made from pipe) and fiberglass in between to fill any gaps. It worked ok. That and the heat sink should give me a pretty good system.
If a pro is welding on anything thinner than about 22 ga., I'll bet he's using a backing plate and maybe a heat dam.
Thanks gents
