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  1. #1
    Seaman
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    Default How do I thin epoxy resin for plywood coating?

    I have read that you may thin resin with acetone at a percentage to saturate plywood before you actually apply fabric, so that it penetrates deeper and then you use resin at full strength epoxy resin on top when you apply fabric? Would 10% be good and is that by volume before adding epoxy hardener or after adding the hardener. I will let these cure for a couple of days before I apply fabric. Any help is appreciated.

  2. #2
    Seaman
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    Default Re: How do I thin epoxy resin for plywood coating?

    bzajdek,

    Yes you can thin epoxy with acetone and you would add it after you have thoroughly mixed the hardener. I did the same thing using acetone and I believe it evaporates too quickly to allow the thinned resin to really penetrate. I have heard that you can also use xylene,toluolene (sp?), mek or denatured alcohol. I have never tried any of these. You can also use CPES but it is very expensive. That is what I have used to really penetrate the wood. Do a search on here and you should find somemore info. If not I'm sure a few guys in the know will chime in that have had experience thinning resin.

    Mike
    '73 slickcraft ss 235

    '92 starcraft 170 dc walleye

  3. #3
    Admiral
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    Default Re: How do I thin epoxy resin for plywood coating?

    You're better off not thinning it, adding solvent will lower the viscosity, but it also degrades the resin, physical properties drop when you add anything not in the original formula. Is also does little to help penetration, so you don't really gain much for the downside of weakening the resin. Some people claim adding as much as 50% of some type of solvent works great, but if you’ve ever seen what it does to resin you’d think differently. This applies to both epoxy and polyester. Many of the penetrating epoxies on the market are just normal epoxies with a great deal of low cost solvent added, then they jack up the price.

  4. #4
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    Default Re: How do I thin epoxy resin for plywood coating?

    ondarvr,

    I have heard that also. (from someone who sells thinned epoxy, but there solvents don't ) When you say it degrades the resin. What properties are sacrificed. Strength, Waterproofing, adhesion, etc ? The reason I ask is the only place I would like to use thinned resin is to saturate my plywood before glassing to penetrate the porousity of the wood, hoping to delay the eventual decay, which I wouldn't think would suffer from a loss of strength. The strength will be achieved when its glassed. (im talking stringers, bulkheads, sole etc. Not necessarily the transom, although I would like to saturate all cutouts and drilled holes in the transom as well. I think this is what bzajdek is after also.

    Thanks, Mike
    '73 slickcraft ss 235

    '92 starcraft 170 dc walleye

  5. #5
    Admiral
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    Default Re: How do I thin epoxy resin for plywood coating?

    Every property you mentioned is reduced by adding solvents and there is little difference in penetration, plus if the wood gets wet it will rot with either product.

    Thinned epoxy is less water resistant and will absorb water faster than unthinned resin.

    Apply a coat of epoxy and let it soak in, repeat this until it won't suck any more up and then glass it.

  6. #6
    Moderator Bondo's Avatar
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    Default Re: How do I thin epoxy resin for plywood coating?

    Ayuh,...

    The whole Penetration thing is alittle overboard,.... Really...

    If you take a piece of epoxied plywood,+ Bust it...
    There's Wood stuck on the inside of the epoxy,.. It's Stuck,... How deep do you need,..??
    As for the Rot factor,...
    Wood usually rots because of untreated Screw Holes....
    The wood Rots from the holes in the center Out....

    For stringers, bulkheads, etc,...
    You can either build so the strength of the wood itself is utilized, as a lighter lay-up,...
    Or,..
    You can use the wood to support the lay-up til it sets,+ the lay-up will be All the structure needed to keep your barge afloat...

    Personally,....
    Draining Water away from whatever composition you dream up is the #1 thought going into Any lay-up for a hull...
    Boats, Will take on water,.. somehow, some way,...
    As long as drainage allows for drying,... Everything else will just fall into place....
    Any Grease is Better,..... Than No Grease at All.......

  7. #7
    Seaman Davinciman's Avatar
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    Default Re: How do I thin epoxy resin for plywood coating?

    Quote Originally Posted by ondarvr View Post
    You're better off not thinning it, adding solvent will lower the viscosity, but it also degrades the resin, physical properties drop when you add anything not in the original formula. Is also does little to help penetration, so you don't really gain much for the downside of weakening the resin. Some people claim adding as much as 50% of some type of solvent works great, but if you’ve ever seen what it does to resin you’d think differently. This applies to both epoxy and polyester. Many of the penetrating epoxies on the market are just normal epoxies with a great deal of low cost solvent added, then they jack up the price.
    I agree with what Ondarvr said.

    Thinning the resin reduce the amount of "solids" in the product. The more solids; the stronger and more durable the product is.

    I have used Hi-Solids epoxies which have zero solvents in them which makes them low VOC (volatile organic compounds)compliant.A good thing if you live
    in states strict on those compounds...ie California.

    These are durable as hell and self leveling to boot. I have never thought about using them in a marine application until now.

    I have, however, used moisture cured urethane on a previous "patch" job on
    a deck that showed ZEROsigns of failure in more than 2 years. This maybe what i am going to use on my proper fix, currently underway, as it showed such promise. (see photo).

    These products are considerably cheaper than resin.

    I will keep you all informed.

    Hope that offers a little bit of clarity, while not being too long winded.

    Cheers Guys
    Attached Images Attached Images
    Last edited by Davinciman; March 8th, 2009 at 08:43 PM. Reason: punc

  8. #8
    Petty Officer 2nd Class
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    Default Re: How do I thin epoxy resin for plywood coating?

    Before thinning epoxy read this article.

    http://www.seqair.com/skunkworks/Glu.../Thinning.html

  9. #9
    Moderator Bob_VT's Avatar
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    Default Re: How do I thin epoxy resin for plywood coating?

    You have replied to a thread that is 9 months old.......
    This is a great link to boat specifications http://boatspecs.iboats.com/
    Please, shop iboats first!!


  10. #10
    Moderator Bondo's Avatar
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    Default Re: How do I thin epoxy resin for plywood coating?

    Quote Originally Posted by Bob_VT View Post
    You have replied to a thread that is 9 months old.......
    Ayuh,.... But it's a Good 1 though,....
    Any Grease is Better,..... Than No Grease at All.......

  11. #11
    Petty Officer 2nd Class
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    Default Re: How do I thin epoxy resin for plywood coating?

    Yeah, but it was the second result I saw when researching the topic. I thought I might save sombody some headaches and maybe their life by referrring them to the article I found as the 1st search result.

  12. #12
    Moderator Bob_VT's Avatar
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    Default Re: How do I thin epoxy resin for plywood coating?

    Do me a favor ...... re-post the exact information in a new thread and title it "Before thinning epoxy read this" and re-post the link.

    It is a good article and it would make a better impact that way.



    Then I will close this older thread.
    This is a great link to boat specifications http://boatspecs.iboats.com/
    Please, shop iboats first!!


  13. #13
    Captain friscoboater's Avatar
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    Default Re: How do I thin epoxy resin for plywood coating?

    I did not thin at all. It really did a nice job.

  14. #14
    Lieutenant Commander
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    Default Re: How do I thin epoxy resin for plywood coating?

    I let the plywood warm up in the sun to let the pores open up so to speak.

    It seems to have made a difference as I used more epoxy versus the other wood work done on a colder day. The stuff done on a colder day seemed to me at least as to not show as much grain after my first pass.

  15. #15
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    Default Re: How do I thin epoxy resin for plywood coating?

    Quote Originally Posted by Bond-o View Post
    Ayuh,.... But it's a Good 1 though,....
    Bond-o

    What's with the "Ayuh" at the start of every one of your posts?

    In my experience that's a Maine thing, and you're a long way from there on Lake Ontario on the western edge of upstate NY...

    Inquiring minds want to know................

  16. #16
    Petty Officer 2nd Class
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    Default Re: How do I thin epoxy resin for plywood coating?

    Quote Originally Posted by Bob_VT View Post
    Do me a favor ...... re-post the exact information in a new thread and title it "Before thinning epoxy read this" and re-post the link.

    It is a good article and it would make a better impact that way.



    Then I will close this older thread.
    Will do.

  17. #17
    Moderator Bob_VT's Avatar
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    Default Re: How do I thin epoxy resin for plywood coating?

    Guys this post is closed however, in reference to thinning epoxy....... read this http://forums.iboats.com/boat-restoration-building-hull-repair/before-thinning-epoxy-read-365255.html

    Thanks Bob
    This is a great link to boat specifications http://boatspecs.iboats.com/
    Please, shop iboats first!!


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