all of this plywood sealing info is killing me

[swade]

Hi i'm just redoing your standard deck boat seat cushion upolstry (so visual or uv protection not important) Not really thinking, the ply i picked up was cdx from home depot,etc.

Just from reading please confirm if i'm right or wrong on choices to seal, I'm not reupholstering right now, but likely will in a few years so it doesn't have to be forever type quality.

epoxy penetrating resin

Epoxy thinned with acetone

I guess poly resin is out of the question? can i just thin it with acetone and brush it on?

Do i need to glass it?

On the low end I guess spar varnish, or exterior paint?

The penetrating resin seems the most costly but are staples going to negate it's purpose? Just wondering which option I should choose, it's all confusing.

[swade]

actually let me clarify, the ply i bought and cut was pt cdx, so i guess this is pressure treated sheathing. But my understanding is I'll still need to seal it. Would simply painting it buy 5 -7 years or should i just spring for the extra bucks and get the epoxy penetrant? from the look of the old stuff most of the rot starts anyways around staple holes which seem unavoidable, or on flat areas between drainage holes, outside of some composite that seems unavoidable too.

[PAR]

The plywood you have will be stamped with what it is usually. CDX is literally the worst quality plywood available. You can use it, but it warps, twists, distorts, rots and generally is fairly weak. If the plywood is pressure treated it will be green colored and probably very wet to the touch when you purchased it. If the wood is normal colored, then it's not pressure treated. PT is going to last a little longer in your application then regular untreated CDX.

You don't need penetrating epoxy. It's nearly worthless in your application anyway. If you only want 5-7 years of service, use monel or stainless staples and good paint and forget about all the fancy stuff.

[swade]

Hi par, yes it's pressure treated, 5-7 sounds ok for this application, it's florida hot and humid but the boat stays covered, i'm reusing the existing upholstery as it's ok...in a year or three if I still have it i'd redo it. Yes I have stainless staples I'm going to use.

Just curious though what the better way to do this would be though in the future? better wood and penetrating? Is that really going to help much considering it'll have staples, I'd expect water penetration regardless., seems something composite would be better.

[PAR]

Again penetrating epoxy is useless in your application. In fact most novices shouldn't bother with this product as it's a waste of money.

You could use inert materials for the cushion bases, but your cost would go way up. I'd use regular encapsulated epoxy plywood, but a good grade of plywood, then I'd go back and seal the fabric and staples to the plywood with a coat of more epoxy. In the end if they see much use and standing water is permitted to soak the cushions and live on the surface of the plywood, you're just going to have issues. You know as well as anyone that it's care, not materials that really do things in. You could make the cushion bases out of you aunt Millie's week old mashed potatoes, if you took good care of them (dry, ventilated and covered). Okay, maybe not her mashed potatoes, but her green bean casserole for sure.

[gonzo]

Let the plywood dry and put on some exterior latex paint on. Epoxy is probably a waste of money.

[Submarine Tom]

There you have it: good advice AND humour.

What more could you ask for.

-Tom

[swade]

Hi guys, thanks for the opinions and info, I'm going to go this route....for what I'm doing i think it makes the most sense.