On a 2002 Jetta TDI, there is dirt collected at the bottom of the fender near the door hinge area. After removing the rotting fender, I find that there is some rust penetrating the structure below it. It looks like I could clean that up, and form a 3/16" patch and MIG it into place. Except at one point the structure appears sound.

Can anyone with body repair experience provide any guidance?

My thought is to clean out the rust, patch it, and then rust treat the inside of the structure.


under fender

  • Some good quality images of the area would go a long way here :o) May 3, 2017 at 0:45
  • I added a picture, which is pretty up close and personal. I'd love some commentary!
    – mongo
    May 22, 2017 at 1:29

1 Answer 1


This section appears to be pretty far gone from the picture. Take a body hammer or a thicker screw driver and tap/stab the metal to see where it is brittle. Your best bet is to strip the paint off to see how far the compromised area actually goes. From there you can cut out the metal, form a similar piece and weld it in.

  • That is what I am thinking of doing. It is bad or marginal, until about 4 inches from where the picture ends. Then it appears to be just fine. 18 ga sheet metal for forming?
    – mongo
    Jun 1, 2017 at 21:56
  • It appears bad. Most likely spread past the paint on the left. You won't know until you cut it out for sure. As for steel gauge, use what is similar. If you do not have a lot of experience welding, go for something a tad thicker just so you don't burn through. Jun 2, 2017 at 14:31

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