Epoxy not curing

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beck3906

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I glued a number of items and the eproxy is not setting. Can hardener get old and not work? Tubes just slide out after 2 days.
Seems like there's only the resin on the tube. But I'm almost sure I used both psrts

Is there a way to dissolve the epoxy?

Thanks.
 
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Yes, the hardener in epoxy is what degrades and can go bad over time especially when exposed to air and humidity. Sometimes, but not always, more yellowing than normal is usually a sign of oxidation which can degrade its performance. The resin on the other hand does not degrade nearly as fast and can last years beyond the hardener.

As far as cleanup there are several solvents that are effective with epoxy resins. Wipe off as much as you can, then use acetone, MEK (methyl ethyl ketone, or methylene chloride (dichloromethane). Any of those should work. MEK is stronger (harsher?) and has a slower evaporation rate and a higher boiling point. Acetone is somewhat less toxic than MEK and is often considered a suitable replacement. Acetone also works on a wider range of materials.

Both however are pretty effective at dissolving many kinds of plastics so be careful when using them on and around plastic stuff.

Dave
 
I agree with what Dave wrote above! There is one other item that can clean epoxy resin - Xylene, but it only comes in gallon containers mostly.
 
I suggest you make up a batch on the side and see if it kicks off. Maybe you did not use both parts but that would be a way to find out. What epoxy are you using and how old do you think it is. I have had T88 at times that was 2 years old and still kicks off. yes the one part is a little more orange but it worked. It is the resin that gets old and hardens. Not the hardener. That is what I found.
 
After three days. Most of the items showed little sign of being cured. I had to slide the tubes out and clean everything so I can repaint blanks and epoxy the tubes in correctly. The acetone suggestion worked.
 
beck3906 said:
After three days. Most of the items showed little sign of being cured. I had to slide the tubes out and clean everything so I can repaint blanks and epoxy the tubes in correctly. The acetone suggestion worked.
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I'll throw my vote in for System2 T88. It is amazing epoxy. I have had my T88 resin crystalize, however putting the bottle (capped and sealed) in some hot water for a while will restore the resin to its viscous fluid state and its fine again. My T88 is a bit over half gone, I guess, and its a couple years old now I think, but it still works superbly well.

The other epoxy glue I use is JB Weld 5 minute. This stuff doesn't cure as hard as T88 (especially when T88 is cured at 150 degrees), and retains a little bit of flex. However, I don't think I have ever had any of it go bad, and I've used bottles several years old before. In fact, the bottles I have now (as of yet unopened) I think I bought over 2 years ago, but the hardener shows no signs of having yellowed or otherwise aged (these were kept in the dark and relative cool for their entire storage time.)
 
I used two part epoxy for coating threads on fishing rods. I always left the cup and stick out to check the cure. Usually less than 10-12 hours.
Definitely something was wrong if it didn't cure within three days.
 
I have been using Bob Smith Industries BSI Epoxy for at least 30 years and have never had it fail. I built RC planes with it and had no failures. I have used it when it was several years old and it was fine.
I have lived where humidity is generally low since 1980, so that may have something to do with it. High humidity might cause it to fail. And my garage stays between the low 50s and low 90s all year. Not sure if temperature causes issues with it.
And as others said above, I leave the leftovers on the mixing pad to make sure it sets.
Someone here mentioned in a post a long time ago that denatured alcohol (DNA) will remove epoxy until it sets. It might be a little less toxic than acetone and MEK. Can you even get MEK any more? Just googled it and it appears MEK is still out there.

Mike
 
Mike said:
I have been using Bob Smith Industries BSI Epoxy for at least 30 years and have never had it fail. I built RC planes with it and had no failures. I have used it when it was several years old and it was fine.
I have lived where humidity is generally low since 1980, so that may have something to do with it. High humidity might cause it to fail. And my garage stays between the low 50s and low 90s all year. Not sure if temperature causes issues with it.
And as others said above, I leave the leftovers on the mixing pad to make sure it sets.
Someone here mentioned in a post a long time ago that denatured alcohol (DNA) will remove epoxy until it sets. It might be a little less toxic than acetone and MEK. Can you even get MEK any more? Just googled it and it appears MEK is still out there.

Mike
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I have always been a bit afraid of MEK. I have long had issues with my eyes, and I tend to wipe them a lot. MEK is one of those compounds that can cause blindness if it gets in your eyes (which is insane, as there used to be MEK-based "medicines" for the eyes!!) If I lost all but one of my senses, I'd prefer to keep my sense of sight...so, yeah, MEK always scares me a bit. :P
 
Mike said:
I have been using Bob Smith Industries BSI Epoxy for at least 30 years and have never had it fail. I built RC planes with it and had no failures. I have used it when it was several years old and it was fine.
I have lived where humidity is generally low since 1980, so that may have something to do with it. High humidity might cause it to fail. And my garage stays between the low 50s and low 90s all year. Not sure if temperature causes issues with it.
And as others said above, I leave the leftovers on the mixing pad to make sure it sets.
Someone here mentioned in a post a long time ago that denatured alcohol (DNA) will remove epoxy until it sets. It might be a little less toxic than acetone and MEK. Can you even get MEK any more? Just googled it and it appears MEK is still out there.

Mike
Click to expand...
Pyridine, a primary additive in the denaturing of alcohol, is considered poisonous. MEK is also used as a denaturing agent. Inhalation of DNA vapors, and/or skin contact can be toxic according to reports from Marathon Petroleum Corporation and University of Maryland, respectively. Personally, non-permeable gloves and a respirator rated for organic vapors (NOT a dust filter mask) are worn whenever working with DNA.
 
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