I've been MIG welding quite a bit of sheet metal today. A couple of times I had to deal with some gaps and the metal was a bit thin for my welder's lowest heat setting.
Tired of blowing holes? Coat hanger to the rescue! Yep, a good use for those old wire coat hangers...
Kind of like gas welding with a torch... feeding the rod into the pool. You can feed the coat hanger into the area you are wire welding and fill the gaps. Get some filler in there and melt it into the sides... Works quite well.
Works good for small holes too... lay the wire across, melt off pieces as you need. Then melt it across and grind it off flush.
I'll start my progress thread soon too, but just thought I'd share a quick tip that came in handy today.