Re: Spar Varnish....
Steve Schoene
>Pine wheels for ground contact are going to be a challenge. Forget a clear finish--none, not even the best marine spar varnish at $30 a quart is likely to save them. (They don't sell this varnish at many paint stores and at no "big box" stores.) I would use a weather protective wood such as white oak heart wood, teak, walnut heartwood, ipe.
If I had to use the pine, I would use a gloss exterior oil based enamel, the best I could find, perhaps even a marine grade paint. If I didn't want to redo it every couple of years, I would first use several coats of a low viscosity epoxy, such as from Smith & Co., and then coat with the enamel according to the epoxy instructions. The epoxy slows water vapor transfer, and the pigment in the paint protects the wood from UV. You then need to sand and recoat the paint whenever it starts to get dull.