epoxy stays sticky

Joey 23 years ago

The UHU plus 2 component epoxy normal 20 hrs 2x20ml, stays sticky. Cured at

25C for 48hrs+ equal amount of binder and hardner. It does become hard but the outside remains sticky. The manual and the packiging does not say a word about how long it will stay good. Does epoxy have a best used before date?

Regards, Joey.

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Mike Norton 23 years ago

As to epoxy softening if heated above its curing temperature - I've had it happen. I used to rewind slot car motors (before they got so high tech a hand winding could not compete). I used epoxy to hold the winding together. If you just ran the motor after the epoxy cured, the heat would soften it and the winding would come apart. However, curing at 220 degrees F (about

105 C) would make it soften, then harden into a rock. (This was 1967 or so.)

About 3 years ago, I glued a wing joint together with over-age epoxy. It didn't harden in a week. I put it up in the attic near the roof peak for a week in the middle of an Alabama summer. It was _hard_ after this treatment. When the airplane finally ran out of sky suddenly, I got to look at the joint in great detail. It was solid.

-- Mike Norton

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M-M 23 years ago

But if the smallest amount of part A somehow makes it into part B, all deals are off.

m-m

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