You can get repair lower outer skins for the 4-door.
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These have a swage rolled into them. Cut the lower skin off the door so it fits into the swage, then punch holes in the door skin lower edge and plug weld into the swage of the repair section. The rest of the door structure behind the lower skin is flat sheet, so cut 1.2mm sections to replace any other rotten bits
I've done a few doors now, Its also a good idea to hold the repair piece tight to the remaining door skin with small self tapping screws to ensure the old and repair skin are flush during plug welding and regularly re-fit the door to the gap, with sill finisher in place to ensure it still shuts OK.
I was talking to a bodyman at a well known establishment on here and he was saying sometimes he has to reshape the line between the wing flare and the main part of door. Wish I could do pictures with arrows on.
He also tack welds small plates in 2-3 places between outer and inner skin, before he cuts bottom of off the door. Stops anything moving.
Its harder to get good 2nd hand doors nowadays and they dont allways fit as well as the original. Thats why its worth repairing your own doors. I also believe its a good idea to preserve as much of your car as you can during a restoration- repair rather than replace.
I think i will be able to repair 2 out of the 4 doors, 2 are beyond repair at the bottoms though, the rust has eaten into the internal structure,
Ill get some pics up at some point.
YG
Ultimate rust cure for your moggy....paint it brown, at least that way you dont notice the rust as much!!