Best varnish or polyurethane for patio benches and handrails (midwest)

I usually use marine polyurethane that they use on the wood in boats. I used it on a set of steps we replaced out our back door and two years later after two winters and four dogs going in and out the back door constantly it still looks brand new.

Epifanes varnish. Sand it so smooth it's like a babies butt. Tack cloth. 1st coat cut with 40% mineral spirits. Sand with 320 grit after it dries. Tack cloth. Next coat cut with 20% mineral spirits. Scuff with fine scuff pads. Tack cloth. Repeat. Then make one final coat. It self levels well and has a long open time. Sanding well before the first coat goes on then scuffing properly and cleaning the dust off between coats is the difference between a gorgeous, deep finish that will last for years and a bubbly, brush stroked and uneven mess.

I have a friend that swears by "Spar" varnish.. make for use on boats

marine grade finishes will hold up the best

Agreed on the use of a marine finish