posted 04-21-2004 12:25 PM ET (US)
Bill,I would consider using epoxy resin with a fairing additive instead of what I am assuming you mean 3M 5200 . 3M 5200 is not an epoxy, but a polyurethane adhesive for mounting, sealing deck joints and bonding.
If the boat has bottom paint, repaint you do not need to gel coat however you may consider adding a barrier coat to the epoxy mix.
Check out the West System web site or better yet buy the West System technical book for $ 2.99 WESYS#002-550. It has some great info on boat repair projects. Also look at page 452 of the 2004 West Marine Catalog for more options.