The sides of this small RV are flat glass panels. The vinyl was defective and cracked bad.

Almost done removing glue (using Goof-Off solvent to get it off). The Gel-coat? surface has micro cracks from Sun exposure. Penny is for size comparison.



Did a small light sand w/240 wet and it looks like the cracks and dirt in the cracks will come off.

need a bit more sanding to remove 100% of cracking..

I don't want to grind the dirt into the remaining gel-coat so am washing with Dawn detergent after using the solvent on the glue. Am planning on DA the entire side then Epoxy primer and 2k single stage paint.

What grit should I use on the DA?
Is dry sand OK or do I need to do wet before Epoxy?

Other advice appreciated. This is my 1st big paint job. The good things are, its not a show car. It will be white (code 50U Olympic White)

Well, with RVs I don't know that much however most of the kit cars I have built in the past have subbed out their fiberglass work to RV and boat builders so the general principles about gel coat remain. I have developed a series of filters that I can lay over pic.s. I use them in analyzing damage of wood, metal, and fiberglass surfaces so I can give e-quotes in our business. In your "sanded" pic. I still see a lot of sun damage extending wayyyy... down into that gel coat. If I was working on this surface I would have to consider shooting a poly primer (Slick Sand, G-2, Featherfill, etc.) to help fill in the rest of that micro-cracking before sealing off with epoxy. I'd do something like 180 dry DA, Slick Sand, powdered guide coat (that would tell you if you are "up" past the damage), 180 the Slick Sand dry, then move on to an epoxy.
I mean, you could get away with the hope that the epoxy fills-in and the printing doesn't come through but you could waste a lot of expensive epoxy finding out that it doesn't.

Thanks for suggestion Darrel.
I will 180 DA a section and inspect with magnification.
Not opposed to shooting a poly primer, just wasn't sure what was needed as this is first time doing sun damaged glass.

Really too bad the mfg of the panel (GE/PPG ?)didn't advise the RV mfg that the material wasn't supposed to be exposed to long term Sunlight.

Actually, yours isn't that bad compared to some of the old kit cars that are knocking around. Some of those are so bad the gel coat must be completely removed. Once that's done the surfaces are so chewed that its' a nightmare to go back and establish the "surface."