patch panel/tech ideas and help

Gas, .025 wire, low setting (mine is hobart 220 v, 180. I set it on 1, and 25 wire speed). Search 69 charger rustbucket in b bodies, took some pics. Cut the replacement panel about 2" larger than original cut, screw it at the edges in several places. Use a die grinder to start the cut, about 1/2" from original cut, cutting both panels at the same time. Then, if you can get a variable speed jig/saber saw, use it. With a wide cutting blade; you want 1/8" gap. After cutting a foot, pull back the strip from the new panel, so you can tack/buttweld. Move all over the place, so you don't concentrate the heat.
Wet rag on the welds. I learned the hard way; used a 5/64" disc to cut. A weld, when it cools, contracts, pulling the sheetmetal. Not enough space, it pushes out. good space, it sucks inward. Bondo will fix that. The biggest hammer in the world will not fix pushing out, it will oilcan.
Then finish de-waxer and filler. Evercoat Rage, Evercoat Icing, 3M sandpaper on a 17" long airfile, then block, with long hand file.. Good. Seal behind the panel to keep moisture out.
Weld cutting flappers on grinder from Harbor Freight (no heat). $5. A auto darkening helmet from HF, $45. And after shooting primer on bud's car, we like Sherwin Williams primers. The icing sands easy, as does the primer/filler. Figure out the contours, put tape there, shoot upper, pull tape off, shoot lower.(that adjusts the lines). So much good info in here.
Ospho is your friend, $18 at Ace Hardware.