Hi Bill,

Yes... I see your point. If the skin is painted, I'd agree that no UV should get to the frame, other than around the exposed cockpit area. I wonder though how much, if any, UV gets through say a clear PU coating then through the skin. I know the PU is UV-resistant but does it entirely stop UV transmission ?

All things being equal, I would still use an exterior-grade finish over an interior-grade one as it is bound to be tougher against the environment.

Regards,

Phil.

: Actually coating the frame, other than the tiny little bit that shows at the
: cockpit, is an interior job. Difference between interior and exterior
: finishes is the resistance to UV, under the cover there is no UV getting
: to the wood.

: Btw, conventional varnishes (non-poly) are quite flexible and very resistant
: to cracking as long as they are protected from UV, see above.

: Bill H.