I have to side with tumbleweed35 I have tried all kinds of stuff even tried making some combinations of stuff. Varnish looks like the best to me it requires several coats but if done right its hard to beat it. A good spar varnish is hard as nails and will hold up ok but nothing stands the Florida sun for to long. The solar index in Florida and the Carib is about 97 so figure it out you can make a copper box like a bread box copper is close to the color of teak and you can cook your lunch in it. We had one some of us guys pop rivited togather and heated stuff like a microwave. The teak is cooking like that all day every day.