I have a body work job on my car's roof panel on the 4 edges. I'll probably have to cut a square piece of it including a piece of a previous terrible job that I paid for, then weld a patch to replace it. The position of the repair seems to make a butt weld easier than a lap weld, but I have one problem. The position of the patch is on the joining of 3 panels: The roof panel, the column panel and I believe a panel that goes through the top of the windshield, where it's glued at.

Besides being careful trying not to cut through the panels below the repair, is it a problem that I just weld the beam with the new patch laying on top of the other parts? I imagine there are big chances the weld beam might catch on the underlying part and I'm not completely sure that's just the way it's done or if in those situations or if I'm expected to remove the whole panel, do the fix and then do the spot welds to fix the roof back in place.

Removing the whole roof panel is likely far beyond my skillset, I'm already venturing myself if I'm doing this repair which is not the easiest considering the position. I'm just weighting the pros and cons of trying it myself or paying another expensive fix on a cheap old car. Below is a picture of one of those roof edge fixes, the one that apparently is the worst. I realize I might have to shape the patch to follow the roof molding depending on how bad this rust is under the cracking paint, which will make it even harder.


  • 2
    If that's just paint coming off, you just need to clean around it to see if there's any real issues. What I'm seeing here doesn't look like you're going to need any metal patches (as long as that's paint I see which has metal underneath of it). Aug 28, 2021 at 0:04
  • @Pᴀᴜʟsᴛᴇʀ2 The paint came off because of rust developing underneath it, there is similar cracking on the other edges of the roof (the person who did those repairs didn't treat the sheet before making the patch, so it's rusting on the inside too). Hopefully, if the rust is thin and I can access all the places where it's developing to sand it down, I might get away without needing to weld, but before I remove the windshield to sand it down and find out I want to be prepared for the worst haha
    – IanC
    Aug 28, 2021 at 0:14
  • 2
    If there's no holes, there's no need for a patch. But you do need to arrest the rust. Aug 28, 2021 at 0:24
  • @Pᴀᴜʟsᴛᴇʀ2 True, problem is in some of those edges I can already notice some rust on the underside of those patches (I removed the inside plastic covers to see them). I can hardly access those for sanding and they look a bit worse than superficial rust :/
    – IanC
    Aug 28, 2021 at 11:40
  • 1
    The bare area looks like failure of a fiberglas ( or similar ) repair. Unless that is a valuable collector car , slap more fiberglas on it and paint. I used to do this when rust was more common ; after the second repair it is probably time to junk it . That was the usual end for my cars in the 60's and 70's. Aug 28, 2021 at 17:03


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