The lower part of the doors is a typical rust point on all cars. My Land Cruiser 40 is not different. Luckily you can get replacement parts as the profiles are difficult to produce your self. The skins come in pairs, one inner and one outer. I got mine from CoolCruisers and is over all very satisfied with the fit. The metal was same gauge as original.
Doors can be difficult to weld as it is a large flat sheet of metal that easily can be stretched and warped. Follow rules as outlined in this post Welding sheet metal and weld it slowly.
When starting try to remove as little as possible of the original material. Try to cut as close as possible to profiles that stiffens the door. That means, you cut away what you don’t need on your expensive new parts. I started with the outer skin first, but kept as much as possible of the inner to correctly position the new outer. Then I cut the new outer skin as it in this case is easier to mark the door than the skin.
Then by placing the skin on the door and clamping it down I marked where to cut the door. After that I stitch welded the outer skin in place. Now I could cut the inner part of the door without loosing orientation of the parts. It is important to do this before starting full welding of the outer skin, as this gives you room to hammer out the weld, and then be less prone to stretching.
After welding outer skin all the way both skins was painted with epoxy on the inside leaving blank spots where the spot welds would come. Holes for the spots was drilled in the inner panel. The inner panel did not fit exactly with the original profile in the corners and was a bit wide. See photo. So I cut out one of the corners and hammered the profile on both sides to get a smooth join. The corner was then welded in in the end.
The left door came out perfectly, the right ended up with the dreaded oil can effect. This is when the sheet loses stretch so you can pop the metal in and out with your fingers. The deflection was about 3 mm. But no crises, as this can be fixed by crimping the metal. See Welding sheet metal.
After welding and crimping I painted it as good as possible on the inside using a long brush and plenty of epoxy.
Door steel parts purchased here: https://www.coolcruisers.com/
