Finish for outside mahogany?

[Norris Randall]

Greetings,
I plan to rework an old "outside" bench (cast iron ends) with mahogany strips.
Years ago an old friend (retired from S/W) said there was something better or just as good as poly for this. I don't remember.
What are some of the suggestions you have for this project?
I want to have it finished by June 23 (anniversary married my high school sweetheart in 1954)

I have some 5/4 that I feel is thicker than needed so I may attempt to re-saw or just plane down to ????.
Plan is to make the bench 4 to 5 feet long and it will have individual strips approx 2 to 2.5 wide attached with SS bolts / nuts.l

I'll appreciate all and any suggestions/comments.
Let'er rip. (or crosscut)

[Howard Acheson]

Poly is a very poor choice if the item will reside outdoors for long periods of time. Poly is attacked by the UV in sunlight and quickly fogs, turns yellow and cracks and flakes. This is true of the so called "spar poly" sold at the big box stores. There is no way to put in enough UV inhibitor to truly protect the finish. And, UV inhibitor is eroded as it absorbs the UV and loses effectiveness pretty quickly.

Non-poly marine varnishes are your best choice. Go to a real marine supplied store and look for brands like Pettit, Interlux, Wolsey and, best of all, Epifanes. They are not cheap but they will last the longest. Follow the directions carefully for best results. Even so, they will fog in a year or two and need to be scuff sanded and a new coat applied.

Finally, the only good way to maintain a clear finish on outdoor items is to either keep them under cover when not in use or to have some covers made from UV proteced cloth.