>>>> Will it hold up outdoors?
No, it contains no UV inhibitors. Sunlight will rapidly cause it to get cloudy and then lose adhesion. Minwax does market a product called Helmsman Spar Varnish that is touted as an exterior clear finish. However, it has not held up well in some tests that I am aware of.
As already suggested, a good marine grade non-poly spar varnish is your best choice. Go to a marine supply store and look for finishes from Interlux, Pettit and, best of all, Epifanes.
Last edited by HowardAcheson; 05-12-2012 at 02:55 PM.