replacing curved transom

Ezrider_92356

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how to you get the plywood to make the curved shape of an curved transom i dont see being able to get 2 inches of glued together plywood to bend like that. would you have to use more layers of thinner plywood and glue them together in place? or what are some other methods?
 

JB

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45,907
Re: replacing curved transom

Laminating 8 layers of 1/4" marine plywood to an exact shape sounds like a BIG job, but that is what I would do.

I just don't trust Seacast. No reason, I just don't trust it.
 

wire2

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Re: replacing curved transom

....

I just don't trust Seacast. No reason, I just don't trust it.
I spread a leftover bit of it on a flat surface 3/16" thick, I couldn't break it after it cured. It is super strong and rigid.

The multilayers of 1/4 ply will do it too, but a lot of work and it's still wood.
 

Frank Acampora

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Re: replacing curved transom

You make up a jig, steam the plywood, then after gluing both sides of all pieces of wood, clamp in the jig unit glue cures. Use a completely waterproof glue like a 2 part resorcinol/formaldehyde glue. It's a lot of work.
 

Ezrider_92356

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Re: replacing curved transom

i wonder what the cost compassions of an 8 layer transom of 1/4 inch ply verse sea cast, i assume it would be close to 2ce the cost of an standard transom replacement for a curved? due to the extra sheets of plywood and resin or glue i can take some measurements of my transom in the morning if someone could help me build a material list/aprox cost for each option.
 

Ezrider_92356

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Re: replacing curved transom

also if i were to make a plywood transom what would be the best way to make a templet to cut the new transom wood i have seen post where peopleused the old transom wood as a templet but i dont see how you could remove the wood in one solid piece, if someone could enlighten me it would be apreicated. i have seen examples of people using resin mixed with like sawdust type product to make the glue it seems like insted if you used fiberglass matte and resin it would make for an almost indestructable transom. however i immagin it would greatly increase cost. keeping cost low is important on this project. the more the cost the longer it will take to compleet. sorry if im rambling i have done alot of reading on this subject on this fourm but still have meany questions
 

MikDee

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Re: replacing curved transom

I'm just guessing here, but it's just a thought,,, Maybe you could use 2 pieces of 1/4" plywood, bend it to shape then fasten them together somehow, bolts, or chock spacers, (with a 1 1/2" space between them, & pour seacast, or fiberglass with a wood (chip or sawdust) mix in between, like a sandwich? maybe you could even frame the edges with pieces of 1 1/2" wood of some type that later on you could screw the sides, & bottom into. Anyway, good luck Mike
 

Hoss

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Re: replacing curved transom

i trust seacast it has never let me down.:)
 

reelfishin

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Re: replacing curved transom

I did one on a smaller boat a while back, I used 1/4" plywood. Since the old wood came out in pieces, I took a tracing of the transom from the outside on a large piece of cardboard. I then trimmed and trial fit it into place until it fit tight. I then used that to cut my plywood. I use a liberal amount of resin and attached the first piece and let it set up, I ran that one with the grain vertical, it allowed me to get the curve without distorting the outer hull at all, I clamped it tightly into place with pipe clamps and several boards. I then laminated each piece into place until all eight were in place. It came out solid as a rock and the fact that they were all epoxied together made it much stronger than the loose stack of 3/8" ply that came out. I am sure it will outlive me. I have another one to do soon, I'm just waiting for room in the garage to get to it.
 

Ezrider_92356

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Re: replacing curved transom

did you run the wood grain the same direction on all the layers or did you alternate?
 

reelfishin

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Re: replacing curved transom

I alternated the grain, that was the reason I let the first outer layer set up, once it was bonded to and well reinforced by the resin, the outer hull and that one panel was enough to allow me to bend and resin in the other sheets that had the grain running sideways.

As strong as it turned out, I probably could have gotten away with doing them all with the grain running vertical. The original ply was done that way as well. That boat only got a 40 hp motor, and even the original wood would have held but the outer wing areas were soft from water running down the gunwales and soaking the top outer corners.

I also used epoxy, with a 24 hour cure, so it took longer than using poly resin, but the bond is so much stronger.
 

fixb52s

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Re: replacing curved transom

I think Seacast is a great product. Too bad you have to take a second mortgage out to pay for it though.

If they brought the cost down, they would not be able to keep up with the orders.​
 

External Combustion

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Re: replacing curved transom

The quarters on my fantail launch is fabricated with 1/4 inch ply laminated to 2" thick and 1 1/2" thick planking placed vertically on the ply. The planking was merely for asthetics. I have had no problems.

Resorcinal glue is the only true waterproof glue and it is a pain to obtain here in the US. Epoxy will give very good service and I think you will not notice the difference.

I made up a form out of scrap wood. Used pallets is a good source. I then nailed the first layer of plywood at the edges to the form. Then slathering on the glue and placing the next layer of wood on and clamping heavily I built up the curve one layer at a time. When the last layer was "dry" I cut the final demensions of the transom peices out with a hand circular saw and left the remainder nailed to the form. By doing it that way I was assured that each layer had glue all the way to the edges and I did not have to worry about damage as I took it off of the form.

When I turned the transom pieces curve down on the ground it supported my little 260 pound friend jumping up and down on them with no permanent distortion.

With 8 layers you will not have to worry about alternating the main direction of the 1/4" ply. Fabrication will be easy and somewhat tedious.

Good luck
 

seven up

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Re: replacing curved transom

how to you get the plywood to make the curved shape of an curved transom i dont see being able to get 2 inches of glued together plywood to bend like that. would you have to use more layers of thinner plywood and glue them together in place? or what are some other methods?


You can check out the bendable plywood at http://www.aircraftspruce.com

This bendable plywood may fit your application. It can also be used to set up a mold for the shape you need and then tossed. From reading on their website I get the impression that strength is compromised due to the bending properties. With that in mind, if true, epoxy and cloth between the layers would be my only choice if this bendable plywood were to stay in your transom as a core.

If you give them a call they might be able to give more details on the strength of the bendable stuff.

It's another option.


Enjoy
 

oops!

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Oct 18, 2007
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Re: replacing curved transom

ya know ez.....i been thunkin on this one since your first post....

this may be a way stupid ider...so some one jump me if im out to lunch...

i layed a hardwood floor using thin strips of white oak 3/8 th's i think....they bent over a gradual radius very easy...tounge and groove...unfinished....

if a feller used that material...glued and glassed every layer...and did it in alternating layers it would only take about three hours and be solid as a rock.
and curved perfectly. 5 layers and glass would get you out to 2 ins in a jiffy.

the glass would be your glue and the thin layers would stick to it and hold the curve when laying.

there is the dumb ider of the day... but it would work.

cheers
oops
 
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