I’ve built a few kayaks using epoxy so if I was doing it this is what I would do. Sand down the fuzzy fiberglass. If you have an orbital sander it makes the job easier. Then apply one coat of epoxy to hold the fibers in place and to keep from gaining too much weight. I like to use 635 Thin Epoxy Resin and you have a choice of different hardeners to make the epoxy set up fast or slow. This epoxy is watery thin so you won’t have too much build up and accumulate weight as much as a thicker epoxy. You can buy the 635 at
http://www.uscomposites.com/