Originally Posted by Hydro Junkie (Post 12291729)

That may be true for many epoxies, but not all. This is from the West Systems C&P above:
207 Special Clear Hardener was especially developed for use with West System 105 resin in coating applications where an exceptionally clear moisture-resistant natural wood finish is desired.Improved formula chemistry allows for true clear cure with same UV stability without amber tint. An ultraviolet inhibiting additive improves the resistance of a West System 105/207 mixture to sunlight but the cured epoxy surface will still require the additional protection of a quality UV-filtering varnish.

I know, the last line says to use a a UV filtering varnish for better protection but, in the 30+ years I've been involved with racing scale hydroplanes, I've never heard anyone say they had issues with West Systems epoxy. In fact, the only one I can say I've had issues with was Z-Poxy. I found it to be very brittle when used to coat a boat hull as opposed to WS. I also found WS to be easy to sand with an electric DA as well as sanding bars