Using Treated Plywood In Aluminum Boat

[bomboMt.]

I have some left over 3/4 treated plywood and was wondering if I coat it with varnish both sides or even paint it, what do you think it will be ok?
Ill be using it for flooring on my 12 ft Alum V-bottom.

thanks

 

[GA_Boater]

Welcome aboard.

In short - No. Treated wood has chemicals/metal compounds that eat aluminum.

Get a sheet of exterior grade plywood. I'm not sure of the correct grade to use, but many here do and hope they reply.

I made a slight change to your thread title.

 

[bomboMt.]

thanks for your reply. I'm making sure you also mean not even if coated with a paint or something else?

 

[jbcurt00]

Correct, dont use PT....

 

[bomboMt.]

thanks

 

[Ned L]

Also, 3/4” is twice what you need for any 12 ft boat. (3/4 would be ok for a 40 ft boat)

3/8 ACX or BCX should work just fine.

 

[b.gagnon]

You can't use the Home Depot stuff... But you can use PT as long as it is CCA (Chromated arsenicals)... I believe it is still sold for commercial use. I think it was banned for residential use in the early 2000's. You may have to get it from a lumber yard.
Why not just buy some PVC board? It's not the strongest but it will get the job done!

 

[DouglasW]

CCA has copper and will corrode most metals, including aluminum, in damp locations according to this source:
https://www.google.com/url?sa=t&rct...endation.pdf&usg=AOvVaw2xUiHENQ6yoKWjLupux-Br

 

[fishrdan]

AQC treated (green stuff) is to be avoided at all costs as it will eat your aluminum boat. Aluminum boat manufacturers use CCA treated plywood, but it's hard to find, EPA ban...

A homebrew borate wood treatement can be made from borax, roach powder and antifreeze (google it), boil it up to dissolve the minerals, soak the wood, wash off the excess and allow to dry thoroughly. I used this on my 18' boat's marine plywood, no rot, but I'm in the desert...

I used 3/8" decks on my 14' jon boat, they are more then sufficient. I sealed the decks in thinned polyurethane, then a couple coats of polyurethane (or was it spar varnish?...) they have held up great for 10 years. 3/8 ply has few layers, so the thinned poly (spar?) soaked into all the layers. It's not like 1/2 or 3/4 that will have issues getting the center layers penetrated.

 

[DouglasW]

A lot of misinformation here. The EPA has not banned CCA treated wood.

• In December 2003, chromated arsenicals manufacturers voluntarily discontinued manufacturing chromated arsenicals-treated wood products for homeowner uses.
• However, EPA has not banned chromated arsenicals and does not require the removal of existing structures made with wood treated with chromated arsenicals or the surrounding soil.

https://www.epa.gov/ingredients-used-pesticide-products/chromated-arsenicals-cca

 

[GA_Boater]

Banned or not - Treated wood should not be used in aluminum boats because it is not compatible.

 

[fishrdan]

A lot of misinformation here. The EPA has not banned CCA treated wood.

The EPA forced plywood manufacturers to "voluntarily" stop making CCA plywood available for non-commercial use, thus the reason we refer to it as the EPA ban. Sure the public can still buy it, but it is difficult to get. Shipping plywood isn't cheap...

CCA has copper and will corrode most metals, including aluminum, in damp locations according to this source:

So why do aluminum boat manufacturers use CCA plywood? Surely it can't be good for their boats.

 

[GA_Boater]

So why do aluminum boat manufacturers use CCA plywood? Surely it can't be good for their boats.

They try to isolate the wood from touching the aluminum. I say try because if the wood gets wet, the Chromated Copper Arsenate leeches out of the wood. The copper part is what eats the aluminum.

As long as it lasts until the day after the warranty expires, they are happy.

 

[jbcurt00]

Its also because its KD CCA ply, kiln dried, which most lumber yard PTs are not.....

 

[bomboMt.]

Thanks for the replies and happy to get the forum input. I just got the 3/4 ply next step is to measure my floor area and re-measure.
thanks to all