Epoxy Questions/Testing

I have done two tests of the epoxy butt joints, both times being very careful to mix in the proper proportions,etc. In both instances, I was able to peel the fiberglass tape off the two pieces being joined with a very moderate amount of effort.

Chuck L. and Gary on dwforum both think that the epoxy hasn’t fully cured yet, likely due to our low temperatures. I guess I am being too impatient although I have left them for 19 -20 hours before pulling everything apart. Gary pointed out that it can look cured but not be fully cured. He said that if the tape is at all flexible when it comes off the epoxy wasn’t cured.

I’ll do another test this weekend. We are expecting higher temperatures so hopefully that will make a difference…that and me exhibiting more patience before testing the adhesion of the tape to the epoxy.

Tearaway of tape

Two fingers to lift the tape

3/34

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1 Comment

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One response to “Epoxy Questions/Testing

  1. khanlee

    For the epoxy it’s important to mix it well in the right proportions. After that, applying a layer to the wood, then laying down the material (glas, dacron, etc) then applying more epoxy is s.op. Finally, you need time and temperature. Most epoxy comes w/ information on cure time. Note that some epoxies pretty much will simply not “kick”– that is, begin the chemical reaction– below a certain temperature.
    One thing you can do to make sure your epoxy is well mixed in the proper ratios is to leave a small amount, say 1/8th inch, in the bottom of a waxy plastic container (think cottage cheese, yoghurt etc) in your kitchen. At household temperatures, pretty much any expocy (save maybe tropical resin) should kick and harden within a matter of a few hours. If it’s still soft the next day, then something is wrong.
    It might also help if you were to hit your wood with sandpaper, maybe 150 grit or so, to provide more surface area for the epoxy to bite.

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