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which resin for plywood ?

Posted: Fri Jun 10, 2016 3:23 am
by zensuni
Hi, I'd like to apply resin on my plywood paipo, to protect it a little bit more. Do I have to use epoxy resin, or is polyester resin (cheaper) ok ?
Also, is there an advantage to apply clothe with the resin ? Does it affect the board buoyancy ?

Re: which resin for plywood ?

Posted: Fri Jun 10, 2016 8:05 am
by soulglider
Screen shot 2016-06-10 at 5.04.22 AM.png
Screen shot 2016-06-10 at 5.04.22 AM.png (6.54 KiB) Viewed 3042 times
highly underused element on this site.

Re: which resin for plywood ?

Posted: Fri Jun 10, 2016 8:44 am
by zensuni
soulglider wrote:
Screen shot 2016-06-10 at 5.04.22 AM.png
highly underused element on this site.
I don't like the search feature, I like to browse the old posts randomly (which I did plenty of times), a forum is alive, it is not a library.... Having said that, I respect the decision of the majority, if I get no replies or only replies like yours then I'll delete the post.

Re: which resin for plywood ?

Posted: Fri Jun 10, 2016 10:16 am
by GeoffreyLevens
We do have various degrees of snark here. I think it's a legit question and yes, poly will work just fine. Just in case, depending on oil content of wood, might want to apply a very thin "cheater coat" of resin first to semi-seal it, then after that is fully set, do whatever is next.

Glass will add weight so less float, but also quite a bit of strength though w/ plywood, there may already be enough strength depending on number of layers/thickness/quality.

Re: which resin for plywood ?

Posted: Fri Jun 10, 2016 10:23 am
by mrmike
none. will make the board heavy and less buoyance just use good varnish like minwax poly. I have boards that are over 5 year old still are water tight. just sand it down a little ever 2 or 3 years and reapply some more varnish. cheep and easy. but if you still want to use resin use good epoxy it will last forever. I have made some wood kayaks and used west epoxy.

Re: which resin for plywood ?

Posted: Fri Jun 10, 2016 5:40 pm
by Poobah
I agree with Mike, but it's probably worth mentioning that he was talking about polyurethane when he abbreviated it as poly. He's talking about an oil based varnish that is very clear and dries quickly. If you change the shape of your board, or make a repair, then matching the finish is easy. It's a little more of a problem if you use an amber colored boat varnish. The curing time is also slower on the amber varnishes.

Some people put epoxy resin on the end grain of the plywood, and then finish the entire board with varnish or paint.

Do you know what kind of plywood you have?

Re: which resin for plywood ?

Posted: Mon Jun 20, 2016 9:59 am
by belly rider
In my opinion one of the best products in the world for wood is the WEST system- Wood Epoxy Saturation System
It does exactly what its initials state-- it saturates and SEALS totally wood fibers with EPOXY resin
This system was originally invented in the mid 80's and applied for the construction of Multihulls and Single Hull
racing high performance sailboats

Its was proven that building with wood strips saturated and glued with the WEST Epoxy system resulted in a much stronger
hull then fiberglass and in some cases even stronger then fiberglass mixed with carbon fibre

I still have the companies book that teaches you techniques on building things by building layers of THIN wooden flexible strips
The company is out of the "right" coast (East Coast) :lol: :lol: :lol: :lol:
Kicks aRs :mrgreen: :mrgreen: :mrgreen: :mrgreen:
dave

Re: which resin for plywood ?

Posted: Tue Jun 21, 2016 12:15 am
by jbw4600
I would agree with using epoxy and then varnishing or polyurethaning over the epoxy. West System has to be varnished or it will degraded from UV light exposure. I have used this method on a paulowinia wood board with good success. Entropy resin makes an epoxy for more coating purposes than laminating. It might not degrade from UV. But I don't know. Or you could just paint the thing.

Re: which resin for plywood ?

Posted: Tue Jun 21, 2016 10:27 am
by mrmike
you mean wood strip like this

Re: which resin for plywood ?

Posted: Tue Jun 28, 2016 2:34 pm
by belly rider
WEST system was developed originally for wood strips that Ideally are much thinner then that-- your picture
Actually imagine very thin layers that make up flexible plywood -- each impregnated with WEST Epoxy and layered on top of each other making the desired thickness
I guess you could also soak thicker layers like the ones used for assembling the board in your picture
WEST is actually saturating and sealing each wood fiber from external elements -- water and air
I would agree that after the application you might want to varnish it for gloss/looks

Imagine now if you were to take thin 1to 2 mm wooden strips and overlap them at a 25to 30 degree angle gluing them with the same WEST resin
the outcome would be an increadibly strong board and the flexibility you can "adjust" by choosing how many layers you wanna overlap


Dave :P :P :P