RE: West Systems epoxy
If you are going to perform structural layups, then use epoxy laminating resin to get the job done. Sounds like in this case you are only preparing the surface for painting, so why not just use Minwax single component urethane over 1/2 or 3/4 oz. cloth, it is lighter, easier to work with, more cost effective, and will render as good a surface for painting as any two component finishing resin. Just saying...
Bob