Generally, I find with the first coats of epoxy, light sanding is important. If you sand too much, you run the risk of going through the fiberglass. If you do go through the glass, you're left with an unsightly blemish that kind of looks like rays. Unfortunatly, there is nothing to be done if you've sanded through the fiberglass. many times it's common that with mutiple coats of epoxy, the epoxy itself begins to take the shape of the weave. If you know you've done several coats, you can assume that it's built up enough and sand down to a smooth surface.

If you've sanded the whole boat and need to do more, I suggest throwing another skim coat of epoxy on there. There is no harm in doing so and it allows for more comfort when sanding down and less risk of getting to the fiberglass. If you're pretty sure you've damaged that spot and want a fix, consider doing some sort of decorative painting of sorts. Maybe a stripe or even a vinyl decal.

I'm not a pro at fiberglass and epoxy so I'm sure others will have more to say on the subject.

   also, I don't see any photos.

Wipe the area with a damp cloth. If the blemish goes away and doesn't come back as it dries out, it's just dust/dirt. If the blemish goes away and comes back as the area dries, you have almost but not quite sanded into the glass. A thin coat of epoxy will fix it.

If the blemish just gets wet and stays cleary visible (wet or dry), you've sanded into the glass and there's nothing that will fix it short of removing and replacing the glass. It's time to start thinking of artistic coverups or to declare it the deliberate flaw to show that there's no hubris involved in your build.

Good luck,

Laszlo

I cannot figure out how to attach a photo.  Can anyone help.  I cant cover the spot with paint it is a focal point with inlayed purpleheart,  maple, and the cedar

Back on the main page for the forum, there's a link to info that describes how to post pictures.