welding sheet metal.

Usually, if you get it too hot, the issue will be the sheet shrinking when it cools, and 'sucking in' an area (waves). I managed to suck in a whole vertical strip up and down a panel the first time I tried; I made the mistake of chasing the shrinkage with the oxy welder....doh! If you have a small spot or 2 like this, with some skill in picking where to stretch the metal, you can use a hammer and dollie to beat out the metal and 'restrech' small areas.