Marine-tex or resin?

[Soundslikefun]

The amount of information here is overwhelming. I've replaced the wood in my transom. To get at the old wood I cut out the inside wall of fiberglass. Everything is now glued back together and I'm ready to fill in the gap created by cutting out this piece.

Should I fill the gap with marine-tex and then glass over the top, or just fill it with resin in the glassing process?

 

[ondarvr]

Re: Marine-tex or resin?

To fill it with Marine Tex will cost you a fortune, you can mix your own putty for far less money.

You didn't say what type of resin you're using, but there's many things you can use to thicken the resin to fill the gap.

 

[Soundslikefun]

Re: Marine-tex or resin?

To fill it with Marine Tex will cost you a fortune, you can mix your own putty for far less money.

You didn't say what type of resin you're using, but there's many things you can use to thicken the resin to fill the gap.

I have not picked out anything yet. All the reading I have done here has really done more to confuse me than help. There are so many options, and it's all foreign to me.

 

[jtexas]

Re: Marine-tex or resin?

How much thickness we talkin bout here? It might be you would want to lay up enough fiberglass layers to fill it.

I'm a big fan of marine-tex but ondarvr's right, it's prohibitively expensive to fill in big areas with.

Basically two types of resin -- epoxy and polyester. On your exterior hull only epoxy will do but it's very, very expensive. If it's an interior surface you might prefer to use poly resin. There are a number of materials available to make the resin into a putty for application into areas where the application of fiberclass cloth isn't practical. Resin without filler is brittle.

How bout some pics?

 

[seagull369]

Re: Marine-tex or resin?

jtexas, I'm curious as to what makes polyester ill-suited for exterior applications. I know you said interior use is ok, but would that include using it on a floor that would see a lot of continuous moisture? I know there's a discussion a few posts down about poly. vs. resin, but it didnt touch on that area. THanks.

 

[ondarvr]

Re: Marine-tex or resin?

I have the same question as you about it being ill-suited for exterior use seagull.

 

[oops!]

Re: Marine-tex or resin?

ok seagull.......search peanut butter.....thats your filler.......

polyester resin is fine for the inside or outside of your boat.....your boat is made of it.

the peanut butter can be pushed into the gaps with a putty knife.

there are many gaps that can be created by replacing a transom......can you post pics? that way we can be sure of what needs to be filled

cheers
oops

 

[Soundslikefun]

Re: Marine-tex or resin?

How much thickness we talkin bout here? It might be you would want to lay up enough fiberglass layers to fill it.

I'm a big fan of marine-tex but ondarvr's right, it's prohibitively expensive to fill in big areas with. How bout some pics?

It's simply a 1/4" wide by 1/4" deep gap around the cutout on the inside of the boat. It's about 14" tall and 45" long. I'll get on some pictures one of these days.

 

[BillP]

Re: Marine-tex or resin?

You can use anything to fill it. Plain polyester will need glass fibers for the filler or it will crack. Here's something to think about...the engine will be riding on the bolts to load the transom, not the top of the transom. That means the gap isn't going to be taking hp and doesn't need the strength to do it. The easiest filler may be 3M 5200. It will do it all with least hassle. The main thing here is to make it watertight.

bp

 

[Soundslikefun]

Re: Marine-tex or resin?

You can use anything to fill it. Plain polyester will need glass fibers for the filler or it will crack. Here's something to think about...the engine will be riding on the bolts to load the transom, not the top of the transom. That means the gap isn't going to be taking hp and doesn't need the strength to do it. The easiest filler may be 3M 5200. It will do it all with least hassle. The main thing here is to make it watertight.

bp

That sounds like a nice easy solution. I like it. My concern is that the wood in my transom does not attach in any way to the rest of the boat. It sits inside the two layers of glass, but there are no screws, etc. holding it to the boat. I'm thinking I should make the inside of the transom as strong as I can.

Am I wrong? Does only the outside matter? I like shortcuts if they don't affect the outcome!

 

[Soundslikefun]

Re: Marine-tex or resin?

I'm also wondering if I should go to a smaller outboard. My transom is 1 1/4" thick and I have a 75hp Evinrude. Seems like maybe all that weight may have contributed to the transom falling apart. Is that a typical sized transom?

 

[BillP]

Re: Marine-tex or resin?

I mis-read and was thinking you were only worrying about the top edge of the transom. Yes the new wood needs to be securely fastened to the transom for best strength. It's usually done by heavily glassing all around the edge where it contacts the hull. This gives a flange to take forward thrust. Screws can be added though the flanges to make sure the wood stays mechanically attached. I do screws and glass over them to make sure they stay sealed. It's overkill but gives me peace of mind.

bp

 

[Soundslikefun]

Re: Marine-tex or resin?

I mis-read and was thinking you were only worrying about the top edge of the transom. Yes the new wood needs to be securely fastened to the transom for best strength. It's usually done by heavily glassing all around the edge where it contacts the hull. This gives a flange to take forward thrust. Screws can be added though the flanges to make sure the wood stays mechanically attached. I do screws and glass over them to make sure they stay sealed. It's overkill but gives me peace of mind.

bp

When I cut out the inside of the transom I left about 5" on either end and the bottom, so the parts where it contacts the floor and either sidewall are still intact from the factory.