plywood seatframe sealer options

So I've finally decided to go all in and re-do my upholstery. There's quite a bit of ripped seams, and rotted wood frames. I've got a 1993 ski-ray and the interior is all original.

My biggest question pertains to sealing the plywood I'll be using for the frames. I'm assuming that the original seat frames were never treated, so to last 17 years is pretty good. I've thought about wrapping the new frames in fiberglass, but I'm not sure it's really worth the effort. So I'd like to hear some pro's/con's about the following options. Now remember that these seats will completely cover the wood, so I'm not worried about UV protection, just waterproofing/resisting as much as possible so that I can get another 20 years out of the interior.

1. Just simply use an oil based primer/paint combo.

2. Use spar urethane (helsman).

3. Epoxy sealer? Now does this imply using fiberglass matting?

4. Any other paint on sealer options I'm forgetting?


-John

Re: plywood seatframe sealer options

Of those options, I'd go with two coats of a low-viscosity epoxy resin (no glass or mat, just resin). That's what I did with the plywood backing my bolsters/cushions and such. (P.S., thicken up some epoxy resin with Cab-o-Sil or such and it makes a good filler for voids in plywood edges). I'd expect 10+ years from that, especially if you provide some drainage holes for the cushion foam. Staples will create an entry point for water, though, so you'll never be able to fully seal the wood from moisture.

If you are willing to spend a bit more to ensure 20+ yrs of service, you could go with King Starboard. Harder to staple into than wood, though.