Refurb, and not using Marine Plywood?

So I just got my first boat. It's older, and runs, but needs some fixing up so I'm starting with the interior. I'm re making the seats using the old ones as templets but I'm not using Marine grade plywood because I'm on a tight budget. I've researched that this is OK to do, but I need to either use Epoxy, Polyester Resin, or vinyl ester Resin on the Plywood. My question is use it where? Cover the whole piece of plywood? Or just the edges? If anyone has redone their seats using regular plywood, I would love some info on what you did, and how it turned out!

 

Drummer,

The advantage of marine ply is that the glue is always waterproof, and their are no voids in the layers. This makes the sheet waterproof, and much stronger than a standard sheet of ply. In your application I don't think strength is much of a concern, so as long as it is exterior grade (read waterproof glue) I think you are find.

I would recommend epoxy as opposed to other options since it is easier and more forgiving to work with than the alternatives. That being the case, mix a bit of epoxy per the manufacturers directions, then roll on three coats over the entire piece, top, bottom, sides, ends ect... This will create a virtually waterproof barrier. Be careful about staples or screws into your encapsulated board however, since any hole can act as a wick to suck water into the wood.

 

For something like the seats exterior grade is probably OK. Fir things like the hull and bilges, marine plywood and epoxy are better choices.

 

Thanks a lot guys. This boat newbie appreciates the quick and detailed responses!

 

If you seal cheap plywood with epoxy it will be more expensive and of lesser quality. Use exterior ply with exterior latex paint and it will last a few years.