Marine plywood

[fordtruckin]

In the next year or so I would like to replace the plywood seat tops on my Lund tinner. There are plenty of threads on replacing boat floors but not many on the seat tops. Would a higher quality regular plywood that's sealed with spar urethane be sufficient? This boat doesn't get left out in the rain or take on a lot of water, so the seat tops won't be exposed or submerged in water.

[schleprock]

While I don't know the answer to your question, I do know that which ever you choose, do not coat the entire seats with a urethane coating because any moisture that is trapped in the wood will cause your wood to rot. Leave the bottom side unfinished or paint it with a passive primer and not a two part one that will not let the moisture out.

[EZM]

Originally Posted by fordtruckin

In the next year or so I would like to replace the plywood seat tops on my Lund tinner. There are plenty of threads on replacing boat floors but not many on the seat tops. Would a higher quality regular plywood that's sealed with spar urethane be sufficient? This boat doesn't get left out in the rain or take on a lot of water, so the seat tops won't be exposed or submerged in water.

That would last you years and years at a fraction of the cost - I've done the same thing many times.

[fordtruckin]

Originally Posted by EZM

That would last you years and years at a fraction of the cost - I've done the same thing many times.

Definitely seems your a one stop shop for all things marine related! How did you seal your plywood? My plan was to take the old seats off for template, then route the edges before sanding and painting with urethane.

[Hunter Trav]

I've had great luck just using regular plywood and Thompson's water sealer in my boat. Take old seats off to use as templates, cut and router new ones and then do multiple coats of the water sealer over a few days, usually close to 24hrs between coats. This is in a 16' Lund aluminum. Hope that helps.

[Tungsten,]

I ve made seat bases that slip over the benches with cheap ply and left over paint.Lasted years.

[Rdamours]

Depends on how crazy you want to go. I rebuilt my seats with marine plywood and coated in two part epoxy before they went to upholstery. I rebuilt an old aluminum a while back.

https://forums.iboats.com/threads/77...313303/page-12

[fordtruckin]

Originally Posted by Rdamours

Depends on how crazy you want to go. I rebuilt my seats with marine plywood and coated in two part epoxy before they went to upholstery. I rebuilt an old aluminum a while back.

https://forums.iboats.com/threads/77...313303/page-12

No upholstery which is nice! I like the idea of making it nice and smooth with epoxy!

[ghfalls]

Marine plywood is very expensive. For seats, I’d just sand smooth with 80 grit and brush on a coat or two of epoxy glue then paint or upholster, over top of regular exterior grade plywood.

[EZM]

Originally Posted by fordtruckin

Definitely seems your a one stop shop for all things marine related! How did you seal your plywood? My plan was to take the old seats off for template, then route the edges before sanding and painting with urethane.

Yes, lol - I've done enough things "wrong" to have learned a thing or two over the years of owning boats .... so I can only give you my opinion with the best intentions.

I basically cut and fit the sheet, primed and sealed the top bottom and the sides - really soaking and working it into the wood on the edges. I stood the plywood on edge and did a couple "soak in" coats into the side grain again as I had more primer left over.

Similar to you, My boat was also stored mostly out of the rain, but I ran that little tinner (16' Lund SV) for over a decade and it held up just fine. I don't even think the plywood was even beginning to delaminate or peel off at the edges when I sold it over 10 years later. It was in great condition and held up great.

Can't remember the exact primer I bought, but basically went to the paint store and told the guy what I was doing (and told him I had exterior plywood) and he sold me a can of paint/primer and off I went.

As a matter of fact - I did both the top of the seats, but also built a floor front to back.

Obviously, over a longer period of time, and in more severe conditions, the marine ply would last longer, but to be honest, it's wasn't worth the difference in price to me at the time (and probably didn't have the cash to buy it either as a young guy)

[fordtruckin]

Originally Posted by EZM

Yes, lol - I've done enough things "wrong" to have learned a thing or two over the years of owning boats .... so I can only give you my opinion with the best intentions.

I basically cut and fit the sheet, primed and sealed the top bottom and the sides - really soaking and working it into the wood on the edges. I stood the plywood on edge and did a couple "soak in" coats into the side grain again as I had more primer left over.

Similar to you, My boat was also stored mostly out of the rain, but I ran that little tinner (16' Lund SV) for over a decade and it held up just fine. I don't even think the plywood was even beginning to delaminate or peel off at the edges when I sold it over 10 years later. It was in great condition and held up great.

Can't remember the exact primer I bought, but basically went to the paint store and told the guy what I was doing (and told him I had exterior plywood) and he sold me a can of paint/primer and off I went.

As a matter of fact - I did both the top of the seats, but also built a floor front to back.

Obviously, over a longer period of time, and in more severe conditions, the marine ply would last longer, but to be honest, it's wasn't worth the difference in price to me at the time (and probably didn't have the cash to buy it either as a young guy)

Sounds fairly similar to my boat a WS-16.

[Mayhem]

I used the same vinyl decking I covered the floors with. There was nothing wrong with my original seat tops but I liked the look, textured (less slippery) surface and easy clean up of the vinyl. Bought a sheet of 5/8 G1S plywood and used the old ones as templates. Didn't treat either side of the plywood with anything, just glued down to the smooth side and wrapped the vinyl around and under enough to sandwich it between the gussets and mounting surfaces. This was over 10 years ago and it has still held up.

Reminds me, still have the Lund Perma-Ply tops kicking around, need to advertise and get rid of those one of these days...