17' Aluminum Boat Transom Repair.

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
thazard@hotmail.com
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17' Aluminum Boat Transom Repair.

Post by thazard@hotmail.com »

I currently have a 17' 6" Sea Nymph Aluminum Boat, powered with a 90HP outboard motor. The wood in the transom is soft, and needs to be replaced. the transom is roughly 25" x 68" and 2" thick. I believe that the correct way to replace this is with multiple layers of marine grade plywood, bonded together with marine epoxy. Then bedded in place with more Epoxy. I have several hurdles, and my location is one. There are no boat repair facilities that I can find within a reasonable distance that has any experience with this repair. Also, there is no local source for marine grade plywood.
I have run across a source of marine Epoxy that I can secure for $20 a gallon. Would it be feasible to just clean out the deteriorated wood from the transom and pour it full of Marine Epoxy. Possibly with some fibrous materials added? My concerns are weight and rigidity.
Anyone care to weigh in on this? Thank you.

Fuzz
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Re: 17' Aluminum Boat Transom Repair.

Post by Fuzz »

First thing is I have never heard of an epoxy for boat use costing only $20. I would not take a chance with shady epoxy, order a gallon or maybe a three gallon kit from here. They can send it USPS and the shipping cost will not be bad. Have them stick a bag of wood flour in with it and get 10 yards of 12oz biax also. If you absolutely can not get marine plywood I would use ACX. It will not be as good but you should still get 20 plus years out of it as long as it is well sealed.

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Re: 17' Aluminum Boat Transom Repair.

Post by OneWayTraffic »

Depending on the amount of epoxy, if you just pour it in, you will get exotherm and all sorts of issues. If you want to fix it right, fix it right. Since your boat is Aluminium you could get an engineering company to weld in a Aluminium plate to support. Nearly all NZ Al boats are built without wood.

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Re: 17' Aluminum Boat Transom Repair.

Post by pee wee »

I'd consider using pressure treated plywood and gorilla glue!
Hank

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Re: 17' Aluminum Boat Transom Repair.

Post by piperdown »

It's not the top of the line marine grade plywood but you can special order it from Menards. I know there's a Menards in Topeka.

Takes a couple of weeks to arrive after ordering.

https://www.menards.com/main/building-m ... 001&ipos=1
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Re: 17' Aluminum Boat Transom Repair.

Post by fallguy1000 »

Epoxy that thick n deep will catch fire and melt the transom, so don't do it. Even more so in an attached garage.

Best way is to derivet the top, removed the rotten wood. If so, remove the inside aluminum.

Insert a couple pieces of Roseburg marine lumber from Menards bonded to the needed thickness and sealed with epoxy on all surfaces.

Put back together.

May require welding the inside ally skin before you slide the ply in the hole if you had to cut.

But you ought not need to cut. Make a funky vac hose thing and some long chisels and you ought to get the rotten bits out.
My boat build is here -------->

viewtopic.php?f=12&t=62495

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Re: 17' Aluminum Boat Transom Repair.

Post by cracked_ribs »

pee wee wrote: Wed Jul 21, 2021 8:08 am I'd consider using pressure treated plywood and gorilla glue!
There could be types of pressure treated plywood that are different, but generally speaking... DO NOT put pressure treated plywood against aluminum.

The treatment usually has some kind of copper sulfate, I think it is. The boat gets wet - electrolytic corrosion. Happens pretty quick.
I designed my own boat. This is the build thread:

viewtopic.php?f=12&t=65349

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Re: 17' Aluminum Boat Transom Repair.

Post by cape man »

My $0.02...

Check with any local cabinet shops, and see if they have any marine ply or can get it with their next order. I got the BS1088 Okume for my first boat through a friend that owned a cabinet shop. Saved a few dollars over getting it here, which actually cost me over time (he assumed that because he helped me get the wood I would drop everything and take him fishing for the rest of his life!).

You might also consider making your own "plywood" out of some decent 1/4" or 1/2" boards, sealed in epoxy and laminated together with epoxy to achieve the 2" thickness you need, staggering the joints or better yet alternating the horizontal/vertical direction so you get the strength you'll need for that 90. Cover both faces with 12 ounce cloth and you should be good. Is the 90 clamped or bolted? If bolted, you can also run another clamping board all the way across to provide even better stiffness and strength.

Besides the issue with aluminum and galvanization, PT lumber will not hold epoxy well, especially if it is new.
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thazard@hotmail.com
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Re: 17' Aluminum Boat Transom Repair.

Post by thazard@hotmail.com »

My source of Epoxy was a local Market Place add. It ended up being PPG Epoxy coating, not resin. And thank you for the input on thermal issues, that eliminates that Idea. Looks like I'm back to looking for a source of Marine grade Plywood. I believe that i will be making a trip to Western Michigan later this summer. Any leads on a Marine Plywood Supplier between Kansas City and Western Michigan would be appreciated. Thanks for the input.

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Re: 17' Aluminum Boat Transom Repair.

Post by piperdown »

thazard@hotmail.com wrote: Wed Jul 21, 2021 2:07 pm My source of Epoxy was a local Market Place add. It ended up being PPG Epoxy coating, not resin. And thank you for the input on thermal issues, that eliminates that Idea. Looks like I'm back to looking for a source of Marine grade Plywood. I believe that i will be making a trip to Western Michigan later this summer. Any leads on a Marine Plywood Supplier between Kansas City and Western Michigan would be appreciated. Thanks for the input.
This place usually has it in stock. Just call and ask what is available.

http://schuttelumber.com/products/plywoods/
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