Stuggi i love your idea very creative simple cheap and it will work just as good i am going to try your idea and instead of a slide hammer as i dont own one use a rivet gun to gently pull the nail up thought you would just need a block of wood with hole drilled in it should do the job if it...
There is another option that hasnt been mentioned you can try your welder at the lowest setting and pack some copper sheet behind the area you are welding this will take the heat away in the old days they used dampened asbestos as another option i have welded up really thin metal that kept...