Thread: Mountain ash repelling epoxy.
16th Oct 2018, 11:34 AM #1
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?Just Do It !
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16th Oct 2018, 09:30 PM #2
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!
17th Oct 2018, 08:14 AM #3
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 !
17th Oct 2018, 09:11 AM #4GOLD MEMBER
- Join Date
- Dec 2010
- Mornington Peninsula
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.
17th Oct 2018, 01:03 PM #5
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 !
18th Oct 2018, 08:18 PM #6Novice
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- Jan 2009
- Elanora, Qld
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
19th Oct 2018, 07:12 AM #7
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.
19th Oct 2018, 07:36 AM #8
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 !
19th Oct 2018, 07:40 AM #9
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 !
19th Oct 2018, 04:17 PM #10
19th Oct 2018, 06:39 PM #11
. 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 !
20th Oct 2018, 02:52 PM #12
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
21st Oct 2018, 01:27 PM #13
21st Oct 2018, 02:08 PM #14
22nd Jul 2019, 01:32 AM #15Senior Member
- Join Date
- Oct 2010
- Victoria, Australia
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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