Boat Transom....Treated Wood?

[johnston]

Need some advice guys. I am giving our 45 year old aluminum pond boat a makeover. About
all there is left to do is to put in a new transom but here's my question...

Have been told by people who should know that both marine plywood and treated lumber
are not suitable anymore because of new methods used in their processing. Was told
they would "eat up" the aluminum. Ok, I have a couple of 30 year old treated 2 x 12 's
that I once used as loading ramps for a garden tractor. Right now a friend is planing
one of them to size and I intend to use it but....Ya'll think it will be ok?

[PEARL DRUMS]

I would use the new wood Lane. I cant see it rotting out the aluminum anytime soon. I re-did a few transoms in the last 10 years and they look fine yet. Dont forget to tighten the bolts back down after a few months. The wood will dry/shrink a bit and loosen up the bolts.

[lostarrow]

I'm guessing the concern would come from Cuprous Oxide (Green stuff they used to use for Pressure treating ) and Aluminum in contact with each other. The copper and aluminum react when in contact and corrode the aluminum. (That's the big fear with Aluminum house wiring )If you were concerned ,you could isolate the two.I'm not sure how your transom attaches but  you will likely want it waterproof ,No? If the two aren't in direct contact ,it shouldn't be a problem. Not sure why marine ply would be suspect. If it's a smaller transom, you could always go with something like White Oak. It would  last as long or longer than the spruce pressure treated.I've found old barrel staves sticking out of the ground from 50+ years ago still in quite good condition where they weren't touching dirt. Most of the protection in treated wood is on the outside So if you plane it off you are left with little more than spruce or pine and a pile of toxic shavings. I believe marine ply is just a higher grade veneer (no voids) with a more waterproof glue.It's usually mahogany of some sort. I don't think it's treated with anything more than the usual antifungal and insecticide that nearly everything from commercial mills receives. You will also want to make sure your fasteners are compatable with the materials involved.

[johnston]

Thanks guys, I am a little out of my element here. Appreciate the input.

[DGF]

If you're still concerned (although I wouldn't be) you could coat the wood with an epoxy so seal out moisture while also providing a protective barrier between the aluminum and trace copper content found in the treated wood. I'd think the marine grade would be treated differently just for that reason.

-Dan

[seabass]

i used treated on my transom with no problem.my boat was painted first though.

[sleek]

Wipe all oils off the wood first, do one layer of glass on the wood against the side where it contacts the aluminum. After it has flashed, then attach it. Check the list for galvanic metals, to make sure your fasteners are galvanically  compatible. You dont want different metal corrosion. That being said, I doubt marine grade ply would cause you any problems. Be sure to use a rubber washer on your through hull fasteners to prevent future rot. Also, a neat trick, anti freeze soaked into questionable wood will stop rot. It kills all organisms.