jpony645

Is it better/easier to butt or lap weld them? Should I use a flanging tool and drill some holes in the lap when lap welding? Do I flange the quarter or the patch? What size wire should I use for gas MIG welding?

Any other advice/tips you guys can offer?

BLAKE

It's easier to lap weld than it is to butt weld, but the butt weld is better (more seamless). I believe you would flange the patch if you are lap welding.

We'll have to wait for someone better aquainted with welding than I am to answer the other questions.

Mberglo

I lap welded my quarter patches, and butt welded my front fender patch. By far, the butt weld looks nicer when you're done, but the lap weld is easier.

To lap weld, you'd flange the top part. That way the inner fender has the overlapping metal on top and won't catch water. The outside of quarterpanel will be covered in filler, primer and paint, and won't be exposed. The inner seam will get seam sealer.

After flanging the quarter, I fitted the patch, clamped it in place and tackwelded it in. I hopped around with spotwelds until the seam was almost solid weld. You have to do this so you don't overheat and warp the surrounding metal. Once it's welded in place, grind down the welds if need be, and fill with a metal-based filler, not Bondo. Bondo will absorb moisture and crack over time. It's okay to use Bondo after you've sealed the area with Metal2Metal or All-Metal.