Pressure treated ply curing

[Ironside]

I was wondering if you have to season,dry ,cure pt plywood before epoxy sealant?<br />does pt ply not have allot of chemical moisture in it and will those chems affect bonding and penitration of epoxy?<br /><br />Thanks new on the scene and want to do it right the first time

 

[crab bait]

Re: Pressure treated ply curing

i sure wood/would.. some of that stuff is down rite wet..!!<br /><br />pt ply to epoxy is almost a waste.. imho..<br /><br />it checks/splits/cracks so much.. the epoxy coating would be breech big time.. that nasty crackin'-splittin'-shrinkin' stuff..

 

[Ironside]

Re: Pressure treated ply curing

should i skip the pressuretrested and just double up un epoxy<br />thinking 5\8 flooring

 

[crab bait]

Re: Pressure treated ply curing

well supposibly there's a GOOD grade of pt .. but find an afford it.. <br /><br />you gotta live in plywood capital central.!!<br /><br />good grade ABx doug fir.. <br /><br />that's about the best except marine .. an this stuff is a very close 2nd.. an far less cost..<br /><br />an this way you can do now an not have to wait an unknown time for dry-out..

 

[BillP]

Re: Pressure treated ply curing

A long,long time ago...20-40 yrs...the pt processes used petroleum and resins wouldn't stick to pt well. <br /><br />CCA is the common pt process now (for the last 20 yrs) and it holds resin same as non treated wood. The APA did tests to prove it. The boating industry has proven it with 10,000s of boats. Getting the wood dry is the only consideration about resin "sticking" with CCA pt. Wood grade is another topic and the problem to me with construction grade pt ply.<br /><br />About checking...exterior ply will check same as any ply if you only use polyester resin to seal it. Been there and done it. CCA treated ply just sealed with epoxy resin will not check...been there and done that too. My oldest epoxy (no glass)over pt ply is approx 4 yrs old and still looks perfect. I think the epoxy glues the fibers together and the poly doesn't...just my opinion.<br /><br />Oh and I air dried my pt ply a minimum of 3 mos before use.

 

[cc lancer]

Re: Pressure treated ply curing

G4P:<br />Read this info concerning treated virsus plain plywood.<br />To me its more of a preference by the builder.<br />-------------------------------------------------<br /> http://www.glen-l.com/wood-plywood/fiberglass-plywood.html <br /><br />--------------------------------------------------<br /><br />One important comment was this:<br />The effect of the 90% relative humidity led to some failures at the plywood/fiberglass interface indicating poor bond. This occurred for some untreated and treated plywood types.

 

[Ironside]

Re: Pressure treated ply curing

Thank fellas the info on this fourm is impressive. thanks for the link to , its allways good to weed out some of the bigger mistakes in a job before you start because i'm sure I will make some all my own to relate when my resotation is complete thanks again

 

[steelespike]

Re: Pressure treated ply curing

I did a transom circa 1982.Bare PT ply.no paint or sealer. Boat spent April to December every year to 2002 in the water in the north east, winters outside.Little or no care.Still no problems.<br /> I do believe the PT formula has been changed recently You may want to research compatibility<br />with aluminum.

 

[Winger Ed.]

Re: Pressure treated ply curing

compatibility with aluminum. [/QB]

Oh yes. All the bare wood I've ever seen that had been up against bare aluminum,, it's tried to eat holes in the Al.<br /><br />If the Al. is primed, painted, whatever to make it waterproof where the woods touches it; the Alum. will be fine.

 

[BillP]

Re: Pressure treated ply curing

Here's the APA link... http://www.apawood.org/ <br /><br />I read somewhere the CCA process is being dropped for another but CCA pt wood is still on the shelves here in Florida.

 

[Ironside]

Re: Pressure treated ply curing

Aluminum is no problem the boat is fiberglass. Thanks for the link on plywood CC there seems to be allot of discrepince in wood. But at least there is also allot of info to make an informed choice. on to phase 2 the floor is out now iI have to determine if the foam needs to go or not but that is a whole new delema again thanks for the heads up

 

[cc lancer]

Re: Pressure treated ply curing

G4P:<br />Let me give another little tip to determine if your foam is shot.<br />Get a piece of 1/2" pipe, on your grinder sharpen the end,just turn it around and around till it is sharp.<br />Then shove it down to the bottom and get a core sample of the foam.<br />Cut it into sections, and lay on folds of paper towel. Then crush the foam and you can tell instantly if there is water saturation in the foam.<br />I bought a boat 2 weeks ago that, the dealer said the floor is rotten the foam is soaked, and the stringers are rotten.<br />I drilled core samples of the stringers, they are dry, core samples of the foam in 5 places its dry. I have to replace 1/2 the floor and the boat is ready to sell.<br />The floor is rotten in the one area where water run into the boat for at least 2 years through a missing vent. Due to freeze and thaw the floor went bad in one area.<br />Floors go bad from owners not covering the boat when not in use.

 

[Ironside]

Re: Pressure treated ply curing

thanks again CC I will do that this weekend .If the foam is good what can i fill the holes with, i dont realy want to special order foam from the states for such a little job

 

[cc lancer]

Re: Pressure treated ply curing

Get 2 tubes of GE silicon from Wal Mart and pump them full.<br />I like the GE better than 3-M 4200, plus I don't have to pay shipping.