Quote Originally Posted by GT6Steve View Post
Excelllent idea and so obvious. I've got one on the stand ten feet away.

I am clamping it to the steel benchtop and the normalizng took some of the curve out. The cracks look just the same after stop drilling. If I weld one side they merely migrate to the other side.
It may well be time to cut it out and patch it....
Since this is a sheet metal pan, it could be from one of two common structural alloys that are crack sensitive when welded autogenously (i.e., without adding filler metal) . . . AA6061 or AA5052. You must dilute the puddle with the correct filler . . . for AA5052, use 5356, and for AA6061 you can use 4043 or 5356. Even then, if you leave a crater at the end of a bead it may crack. Try a larger stop drill . . . 3/16 . . . which will require you to add extra filler at the end of the bead. Also, drilling a little beyond the visible end of the crack may help as the full extent of the crack may not be visible to the naked eye.