I have wondered about using polyester gloss resin over epoxy as well. I have build a number of sailboards and the polyester gloss resin makes for a great finish. (I have finished the gloss similar to varnish... wet sand with finishing paper, then polish with automotive buffing compound.)

But I checked and the gloss resin I have used for sailboards does not have UV protection. The polyester laminating resin has UV inhibitors added, but not the gloss.

Sailboard builders typically paint over expoy resin layups and leave poly resin clear.

I've also been told that it doesn't bond all that well, although system-3 says it's OK.

Anyway you might want to check on the UV.

: Hi Fellows;

: I wondered about the waiting time while the epoxy cured as well. There are no
: solvents in the epoxies we work with, so there is no outgassing
: whatsoever. The epoxy just continues to get harder by the day, for several
: weeks.

: I am going with polyester resin instead of varnish for the finish, an idea I
: got from the local surfboard factory. I asked how long they wait before
: starting the finish coats, and they said, "Wait?" They sand and
: go. Since both polyester resin and varnish will bond mechanically to the
: epoxy, I suspect varnish might sucessfully be applied quickly as well.
: I've seen this topic discussed often on this forum, but I've never heard a
: poster report that they had a problem from not waiting long enough.
: Anyone?

: Best Regards, Spidey