Here is the new outer patch welded in place. I had to form the body lines, the drop crease, by hand. This will get filler to finish it off.
Above is the other lower corner of the same door. Same process: make a template, cut out the rust, POR-15 the inside, form a new patch, weld it in. And it looks like this. This was a little hiccup. I had the 2 lower corner patches in place, so I rehung the door on the car to check the fit. Unfortunately, despite my template, the edge near the door wasnt right, it was too long. I marked it with a marker to show how much had to be trimmed. Off comes the door again, and I trimmed the door and remade the edge. This is why we trial fit things, if I had found this out later, it would have been even worse to fix. Above is one inside lower corner after patching. I even put strips of metal along the edges to replicate the folded over part of the outer door skin. Looks factory.
After filler and sanding. You can see the "folded edges" I made.
Same area after grinding. I have the 'folded edges' tacked in. Still have to seam weld the edge and finish grind it.
After filler and sanding. Came out perfect! If there is a downside to this work, it is that under normal circumstances, no one will ever see it. It is on the bottom inside of the doors after all. And if they do see it, it will be so well done that they will not suspect that it was repaired. It should look like factory issue.
I dont mind if nobody ever knows it, I will know it, and thats enough.