Body help/advice needed

my 2 cents here: pretty hard to learn to weld on: butt welds. rusty metal, thin sheet metal.. like he said, the mig likes CLEAN metal, no rust or oils.... the usual problem that lap welds will maybe eventually create is where the lapped metal is TOO wide, causing rust to form between the 2 panels. a weldable spray primer here helps. look at maybe Eastwood to see what i'm eferring to. the fit for the butt weld is obvious critical. you might try lap welds, with the lapped material 1/2 in wide. on this thin old metal, I can't see using anything but .023.

experiment with heat and wire speed to get the weld you want. nothin wrong with just short spot welds if you doing it right. then come back and fill in. it all takes practice and FEEL. you will also learn to hear the right sound when getting a good weld.

like he said, you can worp a panel real quick grinding welds down smooth!! be careful on those long outside panels. I like a "flap disc" , remember hit the clean metal with anything les than 80 grit and you will leave sand scratches that will come back to bit ya in the butt. I use 40 grit to smotth off welds, and no coarser than 80 grit cleaning up surface rust on panels, and then smotth it off even more before any primers.

trying to fab your patches for the outer wheel house with compound curves is not easy! you are doing fine IMHO. clean those welds best you can, spray it with a rust cleaning metal product or acid prod, prime it good, paint there, and a good undercoating or even product like Body Schult primer, and it will be great! keep up the good work!!