3m panel bond followed by spi epoxy..

[Hkshifty]

Hello everyone!
I recently did my first panel bond repair on a 98 vw cabrio I was prepping for paint. A couple weeks/ month after the car was finished my panel bond outline was shown in the final finish. You can vaguely feel the outline in the paint job. Pushing on the quarter panel isn’t giving on the repair. Any idea where I messed up and how can I fix this to never reappear again? I did allow proper wait times as this was not a rush job.
I did wet sand the perimeter lines and it seemed to go away. A few weeks later it did return. I used 3m panel bond, w&g 710, epoxy primer, filler, 2k primer, blocked before spraying my epoxy sealer,base, clear. Thank you in advance

 

[dhutton01]

Panel bond should never be on a visible surface. It will ghost if you can see it. The patch would have been better off butt welded and metal finished imho.

Don

 

[ksungela]

As Don said, the panel bond should never be painted over directly. This was recently discussed in another thread but long after you did your repair. Not sure how to easily fix it now.

 

[MP&C]

two layers (where the overlap occurs) is going to have a slower expansion rate when heating up (sunlight) and a slower contraction rate when cooling off in the evening than the single layer adjacent to the repair. This difference in expansion rates will cause a ghost line to show exactly where the repair occurred. As Don said, a butt welded seam that has been planished and dressed afterward will give better results.. Here's a flanged seam in a tailgate repair that was welded. Again, it shows a ghost line where the repair occurred. The attachment method doesn't really matter, the one layer next to two layers is the culprit.

 

[texasking]

Tried a similar repair a long time ago filling a tailgate handle hole. Looked terrible pretty quickly. MP&C (Robert) gives great advice and explanations. Unfortunately, the only way to repair it is to cut it out and butt weld it. Nothing else will work. Paint looks really nice, though