Jim,
I'll try my best to explain how and what I did
First I took Roberts advise and ground the edges off the skin. Next I started cutting the inside to get to good metal, being careful to cut inside where I think I want my line to be. I found pretty bad surface rust a little higher inside than I thought but it was a little bit less than the repair panel
Once I had the door cut back to good metal I trimmed the repair panel to fit and I did use butt joints. While the door bottom was off I thought this a good time to coat the inside of the door with POR 15. I also removed the EDP from inside the patch panel and coated it with direct to metal epoxy primer. Note: the panel did require some reforming on the edges.
Fitted the panel with clamps and used some used some pieces of sheet metal fastened with sheet metal screws to keep proper alignment until I can get the panel tacked in. I use a little Miller MIG with solid wire and gas to carefully tack the panel in. Once it was tacked really well I removed the straps and clamps. Then I just kept working the tacks until it was completely welded making sure I didn't overheat and warp.
I ground off the weld on the outside and then cleaned and coated the inside with epoxy primer.
I had to cut higher on the skin than I originally thought. When I got the inside cut out, I could see where the lower skin had been bondoed during a repaint to hide rust but it was still a little smaller than the repair panel. I used the same procedure to prepare, clamp and weld I used on the inside
I bought the panels from Classis Parts of America and they were about like all of them I've used, they require a little work to make them fit. I've come to expect that now
One other thing, I took a lot of measurements to try and make sure I repaired the door to the correct dimensions and curvature.
