My 1981 Westsail 43 has well-made fiberglass fuel tanks, but one has a small
leak which amounts to perhaps one gallon per month.

Several inches down from the top, I can see and feel glass fibers in one small
area, and I believe that the fuel has, over time, dissolved the epoxy. I
assume that in that area it was just too thin when applied. The builder says he
used "hot-pop" epoxy, but can't tell me what it was or suggest a repair.

Since removing the tank involves removing the sole and part of the galley, I
instead plan to clean the area (I have some special cleaner I got from a
company that specializes in tank-cleaning) and apply some new epoxy.

What type of epoxy to use?

Any thoughts appreciated.

Good sailing,

John