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  1. #1
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    Default Mountain ash repelling epoxy.

    I am preparing some mountain ash (Tassie oak or whatever) touse as gunwale and chine rub strips on a boat I am building. I have applied the first of two coats of epoxyand have a problem in that the timber appears to be repelling the epoxy. Looksas if the timber is oily or coated inwax. The timber is new and sanded before the epoxy was applied. It almost looksto me as if the timber is exuding oil.

    Have attached acouple of photos. The timber will be painted not clear finished.
    Anybody out therecome across this problem?
    Attached Images Attached Images
    Just Do It !

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  3. #2
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    Default

    It looks like surface tension is pulling the resin away from some areas but that the low areas are still wetted.

    I often get something similar, even on second coats. Have used it on "Tassie oak" and not noticed any difference.

    Could it be temperature related? It's more likely to stay as a thin even layer when warmer.
    Cheers, Bob the labrat

    Measure once and.... the phone rings!

  4. #3
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    Thanks for your thoughts. I can see what you mean by surface tension and agree with that point but what would cause surface tension n just one type of imber. Ecalyptus oils coming out of the t imber? It is the only timber I have trouble when coating. I use Bote Cote epoxies always well mixed - I'm baffled.
    I will justsd it back and give it a second coat.
    Just Do It !

  5. #4
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    Default

    Have you tried cleaning the timber with acetone prior to use?

    It just may be enough to wipe any oils away allowing the epoxy to grip. Just a thought.

  6. #5
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    I don't normally clean timbers with acetone unless thgere is contamination evident. If I have to remove bar code stickers(Grrrr) I always clean the adhesive residue off with acetone.
    Thanks or the response.
    Just Do It !

  7. #6
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    Does the same problem occur on the back side of the timber, if not it could be that the problem side had wax or oil applied prior to dressing. What about trying some test pieces using Bote-Cote thinned with 10% acetone and another with TPRDA if not already used.
    The 2nd photo shows numerous small air bubbles under magnification, did you warm timber prior to epoxy to draw in rather than warming timber after application which tends to expel air causing bubbles.
    Just some thoughts from my experience. Good luck

  8. #7
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    Default

    Bote Cote warn us off the white abrasive papers. Any chance these were used? I also heard of pollen causing a similar problem at a particular time of year.

  9. #8
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    I have 4 lengths of 42 x19 Mt. Ash that I am coating. In some cases the problem occurs on both sides on other pieces only on one side.
    I have had the same problen with the same timber in varying degrees on other parts of the boat.
    There was definitely no contamination evident before it was coated, it all looked very good.
    Thanks for your interest.
    Just Do It !

  10. #9
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    I steer well clear of "Non clogging" abrasive papers because of the alleged waxy substance they use as the anti-clog medium. I have read the Bote Cote manual numerous times and noted the warning re. same.
    Thanks for the post.
    Just Do It !

  11. #10
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    Default

    Quote Originally Posted by Patonga View Post
    I have 4 lengths of 42 x19 Mt. Ash that I am coating. In some cases the problem occurs on both sides on other pieces only on one side.
    I have had the same problen with the same timber in varying degrees on other parts of the boat.
    There was definitely no contamination evident before it was coated, it all looked very good.
    Mountain Ash is typically supplied quarter sawn. Is the problem evident on the face grain side or the quarter sawn face?
    regards from Canada

    ian

  12. #11
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    Ian,
    . You've got me there. Just did a bit of research on the web. I know what 1/4 sawn and plain or flat sawn are. Not sure what you mean by "face grain or qtr. sawn face"
    Alan.
    Just Do It !

  13. #12
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    if you look at a stick of quarter sawn timber, one face will be orientated towards the centre of the tree and and the opposite face orientated towards the bark side of the tree.
    The other two faces will be cut in a way that the growth rings go from side to side of the stick.

    What I'm asking is the problem with the epoxy associated with the face that is cut across the growth rings, or the face that has the growth rings on end?
    regards from Canada

    ian

  14. #13
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    Quote Originally Posted by ian View Post
    if you look at a stick of quarter sawn timber, one face will be orientated towards the centre of the tree and and the opposite face orientated towards the bark side of the tree.
    The other two faces will be cut in a way that the growth rings go from side to side of the stick.

    What I'm asking is the problem with the epoxy associated with the face that is cut across the growth rings, or the face that has the growth rings on end?
    The problem is mainly on the face that is cut across the growth rings. I can see the annual rings on both ends of the timber and the same thing has happened on the ends but it is of little consequence as they are very small areas and easy to remedy.
    Alan.
    Just Do It !

  15. #14
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    Default

    Quote Originally Posted by Patonga View Post
    The problem is mainly on the face that is cut across the growth rings. I can see the annual rings on both ends of the timber and the same thing has happened on the ends but it is of little consequence as they are very small areas and easy to remedy.
    Alan.
    I'm wondering if the problem is associated with something "contamination" in the pores of the timber.
    your photo appears to be a piece of plantation grown wood -- perhaps earlier success has been with old growth timber?
    regards from Canada

    ian

  16. #15
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    Just a thought. Are you sure it's repelling both epoxy coats?

    It crossed my mind that you could have developed Amine Blush on the surface of the first coat which will repel the second coat. If this is the case you need to remove the amine blush completely before applying subsequent coats. I used to have this problem badly when using West System epoxy, so I switched to using BoteCote epoxy and had no further trouble. BoteCote does not produce amine blush.. It's great stuff..

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