Damn, I thought that was one of my tricks for thin metal---- building a "bridge" around the area to weld up.
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The very little paint that may be on the inside edge is not going to effect the weld when you are just filling a hole.
i used a piece of copper pipe i flattened it and then set it from the backside and filled in the holes.the welds won't stick to the copper the bigger holes i took a big magnet you can buy them from harbor freight and cut the metal the same size and tack weld then run a bead around it.i am a newb and this worked great for me .snippers work real good cutting the metal to size.
i would do it for $15 an hr