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Old Feb 10, 2002, 11:28 AM
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Shelf life of epoxy?


What is the shelf life of epoxy glue? I have some 30 minute epoxy thats about 10 years old.
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Old Feb 10, 2002, 11:42 AM
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It depends...
But usually I'd say 3-5 years. Test it before you use it on anything important. It will still work as an adhesive, but it probably woudn't be as strong and stiff as fresh epoxy. If it stays gummy, then you know it's time to toss it.
Last edited by davidfee; Feb 10, 2002 at 12:02 PM.
Old Feb 10, 2002, 11:59 AM
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I would pitch it if you notice any increased viscosity (other than temperature change) in the unmixed components . Every time I have used epoxy in this state it has been much more expensive and troublesome to remove the half-cured epoxy than just buying new epoxy in the first place.

Bob
Old Feb 10, 2002, 12:34 PM
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I've had it so long at times that one part(can't remember which) wuld turn hard and white in color. Just put it in heated water on the stove and it goes right back to original consistency and color, cures out just like before.
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Old Feb 10, 2002, 12:57 PM
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Quote:
Originally posted by J Morgan
I've had it so long at times that one part(can't remember which) wuld turn hard and white in color. Just put it in heated water...
Yes, some epoxy resins will crystallize if they get too cold for too long. Heating them will usually un-do this. A microwave or conventional oven is better than water, because the water can contaminate the epoxy.

The bigger problem with old epoxy is usually the hardener. Many hardeners degrade over time... either by absorbing water from the air, oxidizing or otherwise decomposing. Many times there will be a color change in the hardener (usually it gets darker). This is not easily un-done... so it's best to chuck the stuff in the bin.

Again, if it's important, just chuck the old epoxy and get some fresh. It's not really that expensive, compared to messing around with bad epoxy.
Old Feb 10, 2002, 01:33 PM
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I figured I should just throw it away, but it was a full container. It seemed like such a waste.
Old Feb 10, 2002, 04:31 PM
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I think that water contamination is the only problem. I have some that is over 15 years old and still performs the same. I have to re-melt the resin every few years in a microwave and this may help to drive off moisture. Not a food microwave, by the way.

1:1 hardener often has a shelf life of only 2 years. Gougeon says "shelf life of many years" for West Systems epoxy.

Rick.
Old Feb 10, 2002, 04:33 PM
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I tried mixing some up before I threw it away. It didn't set-up properly. It's still tacky.


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