So is it silly to use marine varnish? It sounds like a good exterior
varnish from the hardware store would do just as well and half the
price.

I've used the super durable, very fast drying, polyurethane varnish
left over from re-doing our hardwood floors for a number of non-boat
projects. It's great. I put six coats on a mahogany base for a model
in one day and it looks like I spend weeks on it. The marine varnish
I've been using takes 24 hours before I can sand it easily and put
another coat on and doesn't look any better.

If I was sure about the UV aspect, I'd use that floor varnish on my
(already varnished) exterior teak. It sure would be nice to have it
dry in an hour and be working on another coat instead of worrying
about whether the guy next to me was going to be sanding his white
paint.

Just how important is the UV, Interior/Exterior business anyway? The
marine varnish I put on some of my exterior trim pretty much
disappeared over the season anyway.

--

Roger Long