Sealing Plywood; poly resin, polyurethane, oil based paint?

fishrdan

Admiral
Joined
Jan 25, 2008
Messages
6,989
I've been working on the interior of my 18' Crestliner for a few weeks, finally have all the plywood deck panels fitted and doghouse/casting deck/rear seats built. I was going to leave the wood raw (so it can breathe) and then cover with vinyl, but I'm having second thoughts.

Everything is built out of fir marine plywood so checking is going to happen sooner or later, does it really matter what I use to seal the plywood with? I know glassing the plywood would prevent checking, but I'm not going to glass the plywood. Each finished panel will have 10-20 screws and a jillion staples going into it, so water will eventually get in, even if it's glassed.

Sooo, does it really matter what I use to seal the panels with; poly resin, polyurethane, oil based paint?

I have a few partial gallons of Rustoleum in the garage,,, go for it :rolleyes:
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Sealing Plywood; poly resin, polyurethane, oil based paint?

i have used both rustoleum, and acrylic with good results.
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: Sealing Plywood; poly resin, polyurethane, oil based paint?

It's expensive, but if you seal it with a product called CPES (clear penetrating epoxy sealer) from rot doctor, it will have the best possible life.

hope it helps
John
 

ED21

Master Chief Petty Officer
Joined
Aug 26, 2003
Messages
828
Re: Sealing Plywood; poly resin, polyurethane, oil based paint?

I've used West and Systems 3 epoxy to seal plywood before painting or varnishing with good results. The epoxy needs protection from uv light. The only thing you need to do is sand lightly & clean the epoxy before painting or the paint may not stick or alligator. It's not that expensive and it really protects the wood.
 

BillP

Captain
Joined
Aug 10, 2002
Messages
3,290
Re: Sealing Plywood; poly resin, polyurethane, oil based paint?

I think you are on the path of doing a lot of work and having it rot quickly...in Florida exposure, sitting outside, 3 yrs and it will be very waterlogged and serious rot starting. Plywood doesn't need to breath like lumber so leaving raw will only make it rot faster. Punching a bunch of staples in it will speed up the process. What are the staples for...carpet? If so, seal the ply with epoxy and glue down the carpet. That will make the job last 10x as long as what you are describing. The only plywood that endures outside exposure without being sealed is pt ply.

bp
 

fishrdan

Admiral
Joined
Jan 25, 2008
Messages
6,989
Re: Sealing Plywood; poly resin, polyurethane, oil based paint?

Thanks for the replies.

The staples are for tacking down the edges of marine vinyl flooring, I read it needed to be stapled so the edges don't pull free, true or not? If it does not need to be stapled then I'll just glue it down.

I'm a bit concerned about keeping all the deck panels completely sealed though. Each panel is attached to the aluminum stringers with 8-15 screws, there are also 4 seat bases that are screwed to the deck. What is the best way to make sure all of the screw holes are completely sealed?

I was thinking of taping the bottom of each hole and flooding the hole to seal the grain. During installation I'll apply 5200 (or 4200) to each screw and hole to seal them up. Does this sound sufficient?

With epoxy, do I need to glass the panels also, or just hit it with a few coats of epoxy?
 
Top