My 58 Apache project truck had a sunroof installed, a 15X30 hole was left after removing it. I am tacking in a patch from a donor truck. I cut the patch to fit the hole leaving a small gap that is getting filled with tack welds. Have tacks about 1/2" apart all round. My problem is the patch (or the gap) is shrinking some, now the nice domed top is a bit convex. I was hoping that hammering the welds after its completely welded would stretch enough to pop the top back into shape. Any thoughts would be appreciated. Anybody have a repair do this? Thanks...
Go very slowly.If you are doing this with a mig, make your indevidual tacks on opposite sides and alternate back and forth with plenty of cooling time between. When you get your first set of tacks around, cut the build of weld bead off with slitting disc, clean up the inside of the the weld, and hammer on dolly all the way around to stretch the weld back out. Repeat the process until you are completely finished.
cooling the tacks with compressed air helps, i blow air on them until i can rest my hand on the weld to weld the next tack, which is about 8" apart.
Hey, @ this point, I'd probably cut loose all of your tacks at all but 12, 3, 6 & 9 o'clock and try to restore the normal contour of the crown of the panel. You may have to raise up the center of the panel with a porta-power or friction jack to recrown your patch I always like to tack & hammerweld in small section so I always have control over the shape of the panel. That's not possible if you weld out the panel first, then ''hope'' you can put the correct shape back into the panel. If you're using a squirtgun welder on this I'd drop down to a .023 wire as it takes less amps to melt and thus less distortion. " Meahwhyle, back aboard The Tainted Pork "
It's too late now that you have cut the roof up. But for those who need to do a similar job it is much better to "cap" the roof by cutting the new panel just slightly smaller than the old roof so there is 2 or 3 inches between the cap and the rain gutters. It is much easier to weld the new roof on without distortion. Even better is to take the whole roof and weld the posts.
Each weld wants to shrink. And when they do, they pull some of the crown out of the panel. You'll need a bunch of hammer and dolly work to stretch it back. Concentrate on the welds and the heat affected zone. Do it now, and again after every few welds. The longer you wait, the tougher it gets.
I did the same thing on a Buick Moon roof.Sucks learning the hard way. Looked perfect with just a few tacks. when I tried to weld it with more tacks way too fast and no dolly work It went bloop and sucked in BAD!!!!! I hope I don't ever fuck up like that again
The Jalopy Journal
