Did manufacturers use treated plywood 25 years ago?

[car5car]

If you cover treated plywood with resin will it last forever?
It seems to me resin should prevent water from getting in.

 

[iwombat]

Re: Did manufacturers use treated plywood 25 years ago?

If you could perfectly cover the plywood I would think that would be true. However, there's always some spot - be it someplace on the side, through a void, a drilled hole, or whatever that will allow the water in.

 

[tashasdaddy]

Re: Did manufacturers use treated plywood 25 years ago?

if you could perfectly seal any wood it would last forever. treated is to prevent wood destorying organisms, termite, fungus, not water rot. thats why the say mound dirt around your fence post so the water will run off, not puddle. where does a treated fence post rot. at the surface, not in the ground or in the air. water will destroy any wood, even marine ply, it just takes longer. i say use good exterior solid core plywood, seal it the best you can, and go on with your like. 40 years in the home construction and remodel industry.

 

[sbklf]

Re: Did manufacturers use treated plywood 25 years ago?

I disagree, some treated wood is rated for direct contact with the ground. Sink two 2X4's in the ground one treated and one not and see which one rots first. I contemplated doing what you are talkikng about but always had the question if the coating would bond to the treated wood so I went with composites. Go to http://www.glen-l.com/wood-plywood/boatbuilding-plywood.html They say it will bond.

 

[klos]

Re: Did manufacturers use treated plywood 25 years ago?

There has been a lot of discussion and some heated arguments about this topic on other sites. The question is weather you can get a good bond with treated ply.
The problem is almost always with the fiberglass or lack of. So if installed correctly I see no reason to use T/P

I have had great results with marine ply, douglass fir exterior ply, and now composites.

If I were you and worried about rot I would definitly look into composite core material. Coosa, Nida-core, Airtex, etc.

 

[Zetman]

Re: Did manufacturers use treated plywood 25 years ago?

Can't you just ues a good quality plywood from the local lumber yard Home Depo sells a 5 ply 1/2 sheet for under $20..then seal it with a good primer or epoxy resin?

 

[Yacht Dr.]

Re: Did manufacturers use treated plywood 25 years ago?

zetman, absolutly.

car5car, no..simply coating with resin will not make a lifetime peace of ply. though,properly treated, it will make it repel water alot better.

PS. In what application are you asking about ? deck or bulkhead,stringers or... ?

 

[Boomyal]

Re: Did manufacturers use treated plywood 25 years ago?

If I could have found someone who stocked this locally, I'da used it. They sell a lot of this ply to various manufactures for use in their projects. I couldn't find any retail outlets for it. I got samples of it of it because the Company is local but they do not sell it here. The stuff is priced right, resistant to rot, properly dried and will not reject resin treatment.

http://www.greenwoodproducts.com/xlpanels.htm

 

[car5car]

Re: Did manufacturers use treated plywood 25 years ago?

zetman, absolutly.


In what application are you asking about ? deck or bulkhead,stringers or... ?

I found rotten transom mostly around different holes. When I deside to fix it maybe I will find something else.

 

[Zetman]

Re: Did manufacturers use treated plywood 25 years ago?

zetman, absolutly.

P.S. In what application are you asking about ? deck or bulkhead,stringers or... ?

I was thinking of a boat floor

 

[Nova II 260]

Re: Did manufacturers use treated plywood 25 years ago?

The argument remains the same. treated or non-treated? The real question is, how long is a long time? Organic material is just that organic. Nothing will last forever. Why would you want your boat to last forever? Never trading up or down?
The boat you have was structurally sound at one time. It lasted a long time. Build it back the same, save yoursef a few bucks. It's a used water toy, not a Dusenburg.

 

[steelespike]

Re: Did manufacturers use treated plywood 25 years ago?

.40 PT will last a lifetime. As I have said many times the transom on my Crestliner is about 25 years old unsealed and un painted in the water April to Dec.in the north east,stored outside for 20 of those years.Factory transom lasted barely 5 years.Still going strong.In my opinion anything will bond to PT but it must be well dried before painting or sealing.
My docks, total length about 100 ft X 8 ft is about 24 years old un painted or stained for the first 21 years absolutely no rot but for part of one 18 inch board that I'm sure had the rot when it was treated. Sure the dock got gray and dryed out and a little scraggly but no rot.
You need to be sure the treatment is ok with aluminum.
and in my opinion only reason to seal PT is to minimumize contact if it is indicated.

 

[Robj]

Re: Did manufacturers use treated plywood 25 years ago?

Hello there,

I am in the process of replacing stringers in my boat. Have them all built and ready to put in. I used two pieces of 5/8 fir ply, pressure treated with CCA, lamintated together with poly resin and matt. Fir is the best and strongest. The polyester resin bonds great to it, I had to remove part of a lamination and it came out in pieces. It did take about a month to dry out, it had a moisture content of about 7%, which is very dry. The only problem is that it is not marine grade, there are knots and some voids. Just means I will use a little more cloth. My feeling is, I do not know how long I will keep it, but it may be for a while so why not use pt? I saved some $$ by using polyester which I feel will work just fine.

 

[Coors]

Re: Did manufacturers use treated plywood 25 years ago?

From experience, if you use p/t, lay it flat and weigh it down inside for a month while it continues to dry. That stuff will warp like a pretzel until it is dry.

 

[Robj]

Re: Did manufacturers use treated plywood 25 years ago?

Yes Coors is right. I cut my p/t to the desired lengths and then put blocks inbetween and lots of weight on top. It was very wet when I started. The weight prevented it from warping and it was straight when dry.