I have a piece of fiberglass that will need to be primed and painted soon. I’ve been told that the gel coat has to be removed first. Is that true? If so, what way do you suggest? There are certain areas that are so tight I could never sand by hand, grind, or do anything else to remove it. Blasting it might work after a while, but I don’t think I really want to put that kind of abuse on the part. It is fairly thin in some places, because is was made for racing aplications. Please, help!