We all know the problem causing the paint bubbles is the glue leaching through the roof panel. We know repainting doesn't work and I believe some have tried paint on sealers with no success. Others have even had the bubbles come back years after replacing the entire panels with new glue.

However, what about building a new barrier for the glue, a stronger barrier that perhaps the glue will not react with or permeate through. The idea of a thin layer of fiberglass cloth with epoxy resin, like they use on boats, came to mind. The stuff is much more expensive than regular fiberglass resin, but might do the trick and would certainly be a lot cheaper and easier than replacing the roof panel.

Sand, epoxy, sand, paint.

What do you guys think, could this work?

 

Well it certainly "could" work! The problem is, I think, you don't really know the chemistry of the glue solvents and how they are reacting with the SMC(the top). Therefore anything you do would just be an experiment. If it's going to bubble eventually anyway there's on reason not to try.
I have wondered if another type of glue would be better. And why hasn't GM changed the glue?
Also the door panels are glued to the inner shell and they don't have a bubble problem. What glue are they using on the doors, and why wouldn't it work on the top.
You could also consider a mechanical attachment and eliminate the glue altogether.

 

Thought I would bring this one back up to see if anyone in the marine or body repair industry would have some recommendations on what epoxy resin to try?

As for the comments above about a different glue or mechanical attachment, the goal.is to fix.this without removing the panel as that is very costly and parts are hard to find.

I welcome any experiences from those who may have tried something similar