differnce in plywood

[Blue_Heron]

Originally Posted by 77SceptreOB

How is Polyester resin any more or less pourous than Epoxy resin? Neither is "pourous" as I see it. These SeaCrafts are built primarily out of Polyester resins and are Very water tight. Please explain. Comments?

In a word, osmosis. Polyester resin layups will absorb water. Vinylester is better, epoxy is best. They rate in the same order on secondary bond.

Jim, if I was going to redo a transom, I would probably go with a Coosa core and vinylester or epoxy, probably epoxy because I can get it at a good price, and I'm familiar with its working characteristics. I think of it this way; if I used plywood and polyester, I'd be too old to fix it when it goes bad. If I use Coosa and epoxy, I'll be dead before it goes bad.

Dave