Originally Posted by jpbay
Marine plywood has no voids in the laminations,the glue is the same as any exterier plywood.So for a table top don't waste money on marine plywood,cover it with uathane spar varnish.
You're looking at a life span of 10-12 years for regular ply and probably 15-18 years for marine ply. In that time, the finish will be all beat up and the legs will probably be worn out.
Marine ply is better than exterior ply, but IMHO, not worth the extra money.
If you really want to spend $100 on a sheet of ply, at least get a sheet of that Skidguard-coated marine ply like NRS uses for their side boards and fishing platforms.
Originally Posted by salmonjammer
We use 1/2" MDO. It is a plywood that has a paper covering that is water resistant. It is used mostly for outdoor signs, where it has to stand up to the weather. We paint it well, and it has worked great. Much lighter than 3/4 also.
MDO is Medium-Density Overlay. It's got the same paper that MDF (Medium Density Fiberboard), but the paper is only....paper thin. Once you saturate it, it's about as waterproof as any regular exterior ply. It really takes a finish well. I bet your table tops are really nice and smooth!