PT Wood on Aluminum

[stalker14]

Re: PT Wood on Aluminum

I apologize I just jumped in here without much info for you to go on. Here are some pictures of what I have. The transom will not be just glued in it will be set in place in a track and bolted as well, there is a skin that will cover over the wood and a cap too. Here are some pics?

Corrosion I first noticed?

Cap removed?

What transom looks like inside?

Another shot of corrosion?

Wood looks bad but is okay just has Al corrosion on it?

 

[jasoutside]

Re: PT Wood on Aluminum

it will be set in place in a track and bolted as well, there is a skin that will cover over the wood and a cap too.

Ah, that makes sense.

Bah, that corrosion doesn't look all that bad. I think you could clean it up some, etch, prime, paint, install new transom, game on.

That transom does kinda look like PT to me, course, I sometimes confuse my ear and elbow though.

I can't help but wonder if your transom has been replaced before (not original)? Reason I ask is all your bolts/nuts are rusted there. Steel maybe? Stainless coated in 3M 5200 would be a great replacement for those.

 

[stalker14]

Re: PT Wood on Aluminum

No it is original, I got the boat from the original owner which was my FIL. He doesn't fix anything. The transome was bolted, rivited, and welded together for crying out load. I was amazed at the fact that they used SS bolts with plated steel nuts. What a joke. It is amazing they are not in worse condition. And yes it is not that bad, definitly fixable and I caught it in plenty of time.

 

[ezmobee]

Re: PT Wood on Aluminum

Tracker?

 

[stalker14]

Re: PT Wood on Aluminum

No it is a Sylvan.

 

[lckstckn2smknbrls]

Re: PT Wood on Aluminum

Being an older boat could mean the wood you have is the older type of treated wood.

 

[ondarvr]

Re: PT Wood on Aluminum

It doesn't look at all like treated wood, just plain old Marine type plywood, the corrosion is just from salt water being trapped in there.

The wood looks OK in the pic, I'd just re-use it.

 

[stalker14]

Re: PT Wood on Aluminum

Yea if it is treated it is the older type. What I have decided to do after all the reading I have done on the net, is to just reuse the wood I have. I am going to seal the wood with epoxy and then embed the wood in thickened epoxy to the transom. I am going to use the West System Gflex epoxy for that. This will help to prevent water from getting trapped between he wood and the aluminum, isolate the wood from the aluminum and seal the holes too.

 

[fishrdan]

Re: PT Wood on Aluminum

I am going to seal the wood with epoxy and then embed the wood in thickened epoxy to the transom.

Hmmm, that sounds like you're putting a transom in a glass boat. I wouldn't do that to an aluminum boat as you (or the next owner), will never be able to get it apart again, it will all be glued together. Also, that might not stop all corrosion as trapped water will corrode the aluminum,,, "crevice corrosion".

A couple posters suggested sealing up the aluminum to prevent further corrosion and I agree with that. Apply metal prep to etch the aluminum and convert to the corrosion, thin coat of ZC primer, then paint it. I had slight corrosion under the transom plywood on my tracker (2 years old.....) an I did this to stop further corrosion. I pulled the transom plywood off a year later and everything was fine, no corrosion, just painted aluminum.

 

[jigngrub]

Re: PT Wood on Aluminum

Your transom is CCA (chromated copper arsenate) pressure treated plywood, it is used in boat building and that's the only application it is made for nowadays. The deck and transom of my aluminum Tracker are made out of CCA. CCA is the old pressure treating formula, ASQ is the new formula and the one that is corrsive to aluminum.

Just sand (wear a dust mask) your transom wood a little and apply 3 or 4 coats of epoxy to it, then paint your aluminum with the self etching primer made for painting aluminum. Put everything back together and you're good to go. No need to glue the wood to the aluminum.

Make sure your transom wood is completely dry before applying the epoxy to ensure complete penetration and bonding.

 

[Woodonglass]

Re: PT Wood on Aluminum

You might want to investigate Por-15 for aluminum.


http://www.por15.com/

 

[stalker14]

Re: PT Wood on Aluminum

The reason I am going to glue the wood into place it two fold. One is to help isolate the wood from the aluminum. Two is to prevent water from getting between the wood and the aluminum and actually there is a third reason, the transom is full of holes where it has corroded through form before. The transom will become one solid block.

No, I will not be able to replace it in the future but, what I am hoping is that won’t be necessary. I am hoping that this will be the last time this will need to be done. Wishful thinking I know but I think it will pan out. I know if I use untreated wood I need to allow for this to be done but I am hoping (and praying) that this will never need to be done again. To my knowledge this has not been done before or if it has no one has spoken up yet so it remains to be seen.

The gflex epoxy is supposed to be flexible and should be able to withstand the torque and vibration from the motor. Again, we will see, you never know till you try.

 

[jasoutside]

Re: PT Wood on Aluminum

I think you are going to spend some major cheddar on Gflex going this route ^^^^.

 

[ondarvr]

Re: PT Wood on Aluminum

This is from the Sylvan website.

"Xl plywood floors with a lifetime warranty, you can count on the specially treated floor to hold its strength and never warp or rot"

Not knowing the year of your boat, or if they use this wood in the transom also (I assume they would), it may possibly be PT, the older it is the less likely though.

 

[stalker14]

Re: PT Wood on Aluminum

It is a ’94 Sylvan, the Gflex is $60 for the 32oz package, that is more than enough for what I need.

 

[stalker14]

Re: PT Wood on Aluminum

This is from the Sylvan website.

"Xl plywood floors with a lifetime warranty, you can count on the specially treated floor to hold its strength and never warp or rot"

Yea that is nice, what I have found is most these boats are made up north and Florida is a whole 'nother animal, even the coastal areas of the NW and NE don't suffer the kind of problems we get in the sub-tropical regions regarding rot and corrosion. Fungus is our state flower.

 

[stalker14]

Re: PT Wood on Aluminum

Okay here is a picture of the original wood transom. It is in fine condition even though it is around 18 years old. I am getting ready to start sealing it with a thinned epoxy so that it will soak into the wood the maximum amount.

Here is a picture after several coats of epoxy to seal up the wood. I am getting ready to final sand the epoxy for installation back into the boat.

Here is a picture of the inboard skin that was covering the wood transom after I have wire wheeled the crust off of it. Getting ready to clean it with detergent and then phosphoric acid cleaner/etcher.

Here is a shot of the transom after cleaning, and etching. Getting ready to epoxy in the wood.

 

[stalker14]

Re: PT Wood on Aluminum

Here is a shot of the outside, you can see the light shining through the bolt holes and unfortunately the corrosion holes as well. I will be gluing in the wood using West Systems G-flex thickened epoxy. This will seal the entire thing up and also prevent water from getting between the wood and the metal.

All glued up.

Started removing some of the decking I put in a couple years ago and the copper/aluminum corrosion is obvious here to. I believe this wood is the ACQ treated plywood as opposed to the CCA treated plywood used in the transom. It has a much higher copper content and is really not friendly to aluminum at all.

I think I am just going to go with marine ply for the deck since I don’t have a local source for the CCA marine plywood. I don’t want to spend the $$$ for shipping ply wood. I will just seal it with epoxy. It will last a long time.

 

[stalker14]

Re: PT Wood on Aluminum

Okay a little more progress. I installed the inboard transom skin back into the boat this past week end.
G-flex epoxy 50-50 getting ready to mix it up.

Skin all glued up. Wow, is this thing solid, not flimsy like it used to be, can’t wait to get the top cap reinstalled, maybe next week.