The driver's door that came with the bus appeared to be from the wrong year of manufacture that can determine by the door handle type. I still have not quite figured out whether I'm supposed to be lucky that I found this red front door, since it is much more rotten than the one that came with the bus.
It was even worse when it returned from sandblasting: there were holes everywhere! I did not have much choice though, so better make best of it.
After a lot of measuring and marking, I decided that the time had come to involve the grinder. Unfortunately this front door was to heavily rusted and there were lots of pieces that just were not available in body repair panels. I ended up peening my own pieces of sheet metal to fill up the gaps.
As soon as you have managed to refit the inner bottom of the front door (basically the framework) you can start fitting the outer door skin. Take your time and use clamps to fix the metal to the frame, so it stays in place when you are welding. Start with some spot welds spread from the left to the right. Carefully cool the metal with air and weld in intervals from one side to the other. This will prevent the thin sheet metal from deforming.
Now that you have fixed the bottom skin to the door frame, you can bend the edges around the frame. Use a hammer and a small anvil to hammer the edges of the door skin around the frame. Support the places where you hammer, with a small anvil to prevent the metal from damaging. You will have make some cuts in door skin at the corners; this will make it go around the corner much smoother.
Grind away the excessive welds using a multi layer disk and complete the process with filler and a good primer.
I actually hoped that this would be it, but sandblasting exposed another potential rust threat: the mounting location of the window frame was also heavily corroded. Although it did not look so bad from the outside, I still decided to grind it away and have a look inside. My suspicion was right; rust trying to work it's way out.
More welding challenges: how on earth do you recreate the tapered screw holes? I ended up cutting the old tapered screw holes out of the rusted piece of metal and welding it back onto the new bit. I used a lot of spot welds to fill up the missing bits and pieces, but got there eventually.
