Transom resin soaking ??

[lvl]

Hey guys I have a few questions about soaking my plywood with poly resin before laminating them together.

I have read online that the propper mix of resin to hardener is 1 oz of hardener to 1 gal of resin.

Should I use less hardener to give the resin a longer time to soak in the plywood? If yes what would be the min hardener to resin ratio?

I also heard somebody say they mixed in acetone to the resin for a quicker absorbtion. This doesnt sound very bright to me don't know why but it just doesn't sound right.

Any thoughts or suggestions would be greatly appreciated.

 

[Woodonglass]

Re: Transom resin soaking ??

Most of the guys here on iBoats do not believe that thinning your resin to "Soak" into your plywood is a good practice. It usually weakens the strength of the product. It is probably to your advantage to follow EXACTLY the manufacturers precise measuremnet guidlines for mixing the product.

But it's your project, so you ARE free to do as you wish.

I'm just sayin...

 

[rockyrude]

Re: Transom resin soaking ??

It isn't necessary to seal each piece before laminating, just glue the pieces together and seal the whole assembly. If you look at oop's resto thread you can find out how to extend the "kick" time.

 

[lvl]

Re: Transom resin soaking ??

I am using polyester resin so i should just glue the 2 pieces together with construction adhesive? I will need chopstrand mat to resin it to the outside skin correct?

 

[Bifflefan]

Re: Transom resin soaking ??

I am using polyester resin so i should just glue the 2 pieces together with construction adhesive? I will need chopstrand mat to resin it to the outside skin correct?

No on the construction adhesive, yes on the matt.
Just mix the resin to the manufactures specs and glue the wood with it. It will cure fine.

Wait a minute, what are we working on here?
If you can drop the hole thing in, in one piece then just resin it together and let it set up. then do the outside with resin and drop it in.
If you need to piece it together to get it in (like I did) then resin each piece and put them in as you doing it. I used screws to hold the wood together while setting and then added the matt and resin after.
I have a fiberglass I/O.
Here is my rebuild.
Give it a look. it works great.

 

[jonesg]

Re: Transom resin soaking ??

Hey guys I have a few questions about soaking my plywood with poly resin before laminating them together.

I have read online that the propper mix of resin to hardener is 1 oz of hardener to 1 gal of resin.

Should I use less hardener to give the resin a longer time to soak in the plywood? If yes what would be the min hardener to resin ratio?

I also heard somebody say they mixed in acetone to the resin for a quicker absorbtion. This doesnt sound very bright to me don't know why but it just doesn't sound right.

Any thoughts or suggestions would be greatly appreciated.

Depends what you're trying to accomplish if you thin the resin with acetone, for waterproofing it makes sense because the acetone is an ionic bridge which will carry the resin INTO the wood. The deeper it penetrates the better. I would just pay attention to the edges where moisture will tend to wick up like a sponge.

Its not necessary for construction.

You can reduce catalyst and should do according to mfger directions for different ambient conditions, the resin I buy comes with a graph allowing for different percentages but you have to stay within the envelope for sure.

Many have used the PL adhesive to laminate transom wood and they recommend it highly, I would have gone for resin and mat.

 

[ondarvr]

Re: Transom resin soaking ??

Adding something to thin the resin sounds like a good idea at first, lower viscosity, deeper penetration, what could be wrong with that. The problem is solvents of any type reduce the water resistance and other physical properties of the resin, so while you may gain a very slight amount of penetration (and it is slight) you end up messing with the chemistry of the resin. There should be a sticky at the top of the form page with information about thinning epoxy and what it does to the physical properties even at low percentages, it does the same thing to polyester.

The two sheets of plywood can be glued together or glassed together, its up to you. If you use polyester a layer of mat needs to be used between the sheets to help with the bond.

 

[lvl]

Re: Transom resin soaking ??

OK here's the thing with the mfg instructions. There is none. I got this resin from my uncle who knows a guy that works at a fiberglass manufacturing plant. They make boats and other fiberglass parts. I got a black 5 gallon unmarked bucket of resin and a little clear plastic bottle of hardner (also unmarked). I know kind of shady but I am on a budget and it only cost me $50 and i have faith in my uncle.

With that being said the only thing I have to go on is what I read on the net. Everything I find says 1 oz. of hardner to 1 gal of resin. I think I will stick with that ratio.

Thanks for the advise guys I think I will go with the glue the two pieces of plywood together with a layer of csm and resin. Then put it in as one big thick piece of sealed wood with another layer of csm and resin between the new wood and outter skin.

Now how the hell to clamp it is the next problem.

 

[ondarvr]

Re: Transom resin soaking ??

1 oz per gallon is at the very bottom end of what you can add, so don't go any lower.

 

[lvl]

Re: Transom resin soaking ??

OK got a question on what weight CSM to order. I am going to order some 1708 for the side of thr transom that will be facing the inside of the boat. I noticed that it uses 3/4 oz csm. I am wondering is that to thin to use alone for like a layer between the peices of plywood I will laminate the plywood?

I will also need some CSM for other patchs around the boat like the keel area. Should I just order 1 1/2 oz CSM or do I realy need to order both for the diffrent applications?

I also could just be totaly over thinking this whole thing.:redface:

Thanks for all the help

 

[Mark42]

Re: Transom resin soaking ??

I am using polyester resin so i should just glue the 2 pieces together with construction adhesive? I will need chopstrand mat to resin it to the outside skin correct?

The best product for gluing wood is a waterproof carpenters wood glue. Remember, poly resin is NOT an adhesive, and compared to adhesives, its bond is weak. Plus, wood glue is cheaper than resin and glass, and a heck of a lot less mess.

You may also note that boat manufacturers generally do not laminate up the transom ply with glass and resin, they just glue it with a waterproof glue.

I was using construction adhesive for a while on various wood projects, such as laminating up floor joists. I have since switched back to waterproof wood glue. The problem with construction adhesive is it does not spread well, it skins over in a few moments, and that can seriously impact its bond. So its back to wood glue. Wood glue never failed me.

Besides, what do you think is holding all those layers of wood in the plywood together? It is not poly resin!

This stuff, or Gorilla glue (polyurethane base glue) works well. Either will get the job done.

 

[jspano]

Re: Transom resin soaking ??

Now how the hell to clamp it is the next problem.

my transom, i cut 2 pcs out of top grade 3/4 inch exterior ply, resined them up with cloth and laid them on top of each other. i had some 2x4 that i used to clamp them with. i also used some non rusting deck screws that i sunk into the pcs, that i left in and resined them over when i did the outsides.
you could see the resin ooze out

 

[bigredinohio]

Re: Transom resin soaking ??

For the money, PL Premo is the way to go for laminating. I also believe in not thinning the resin.