Hi Marty;

Epoxy is not all that hard - It remains tough and leathery compared to other finishes. it will not accept the level of polish you can obtain with varnish, or the glassing standby, polyester resin. So in addition to UV protection, you're building a layer that can be buffed to quite a polish.

I use an epoxy product called "Ding-All," and it is loaded with UV protection. On cheaper surf boards, the local mfr has begun skipping any other finish over the epoxy. It survives the intense Florida sun quite nicely. So with the right product, you can skip the varnish step altogether, albeit at the loss of high gloss.

I am wrestling with what to do for the final finish on my yak, and am leaning toward a polyester resin product that is also heavily UV protected. It is as clear as Ding-All epoxy, and the finishes I've seen obtained are truly startling - None of the amber color gotten with spar varnish. Sorta like gel coat but clear . . . ;-)

BTW, varnish has a fairly low solids content, so it can't weight very much at all. The vast majority of the weight is in the volatiles - I would doubt a gallon contained more than 3 pounds of solids, or 12oz/quart - That would place it in the realm of commercial shellac solids density, which seems about right.

Best Regards, Spidey