I'm just learning how to weld in little patches in hidden places but just tried patching a little 1" square in the middle of the door. Well, I welded the whole thing in and by the time I finished it shrunk in and created an indentation. I thought I was going slow and cool enough but I guess not. I didn't realize just how bad it was until my father in law came by and showed me how to check the dips and valleys with a ruler. I put a ruler on and it wouldve have taken 3/8" of filler to level it. So I guess by using that ruler trick I'm going to hammer out the dent to get as close as possible.