You can make it as involved and complex as you want, but I would just use a real good Exterior Polyurethane. I'd sand it down to open the grain a bit, then thin the first coat and put it on heavy and let it soak in for a while. Wipe off excess, and after it dries over night, paint it with poly a few times letting each coat dry for a day in between. It makes it dry better in the long run. I have done this to benches years ago, and they only get screwed up if I do something dumb, but normally they hold up well to use as a gun bench or work bench.

Last edited by reivertom; 02/25/20.