I went to a local Sherwin Williams automotive paint store and asked for a paint stripper that was safe for fiberglass. They sold me a gallon of very thick stripper that the Corvette painters use and guaranteed that it wouldn't hurt the fiberglass on my C-ARF MiG 15. Worked like a charm and took the paint right off. Smelly and messy, but sure did the job. Be sure and use heavy duty rubber gloves, and plenty of paper towels, 'cause the stuff is pretty caustic and will burn your hands. Apply the stripper, let it set until the paint bubbles, use a plastic scraper, and it comes right off. I also used a small brass brush to get into cracks and crevices. You might have to apply the stripper more than once if there is more than one layer of paint, or the paint is really thick. When you get the paint off, kill the stripper by washing the fiberglass surface with soapy water and paper towels. Let it dry, prime and repaint. Worked for me, and went a lot faster than I thought, but was really messy - sure beat sanding or trying to scrape it off. I covered my bench with lots of old newspapers, and got with it. I don't know if the stripper would work on an epoxy based primer or not - my MiG was primed with a standard solvent release primer and flat paint, so it worked really well.

Good luck.

Les