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Epoxy still tacky after 4 days

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Forum topic by Robert212 posted 12-28-2015 01:17 AM 672 views 0 times favorited 12 replies Add to Favorites Watch
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Robert212

2 posts in 349 days


12-28-2015 01:17 AM

Does anybody know a fix for epoxy that has not fully cured? It is just slightly tacky. Thanks for you input.


12 replies so far

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MrUnix

4224 posts in 1662 days


#1 posted 12-28-2015 02:11 AM

Does anybody know a fix for epoxy that has not fully cured?

Epoxy has a temperature range for curing depending on the epoxy/hardener used. If you try to use it outside that range, it won’t cure properly or very, very slowly. Give it some heat. Epoxy is exothermic, and heat will speed up the process.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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newwoodbutcher

552 posts in 2313 days


#2 posted 12-28-2015 02:18 AM

What he said.

-- Ken

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Mark Shymanski

5314 posts in 3176 days


#3 posted 12-28-2015 02:19 AM

Did you mix the epoxy as designed? Sometimes more hardener is added in the hope of speeding up the curing rate. All this really does us waste hardener and perhaps leave unconsumed hardener possibly affecting the cure.

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

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Robert212

2 posts in 349 days


#4 posted 12-28-2015 02:52 AM

I did mix equal parts of epoxy resin and hardener. The temperature was approx. 60 deg. F during curing. I will heat the piece and hope for the best. Thanks for your suggestions.

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conifur

955 posts in 615 days


#5 posted 12-28-2015 03:17 AM

Wifes hair drier!!!!

-- Knowledge and experience equals Wisdom, Michael Frankowski

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clin

513 posts in 459 days


#6 posted 12-28-2015 07:23 AM



I did mix equal parts of epoxy resin and hardener. The temperature was approx. 60 deg. F during curing. I will heat the piece and hope for the best. Thanks for your suggestions.

- Robert212

Not all epoxy is mixed 1:1.

60 F is pretty cool.

-- Clin

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Tennessee

2410 posts in 1978 days


#7 posted 12-28-2015 01:12 PM

How old was the epoxy. Most people don’t realize it has a shelf life. And the obvious question, how long did you mix it?

If after four days it is not cured, heat may help, but my guess is you are scraping it off and starting over.

-- Paul, Tennessee, http://www.tsunamiguitars.com

View Fred Hargis's profile

Fred Hargis

3938 posts in 1957 days


#8 posted 12-28-2015 01:14 PM

While it coud be any of the reaons mentioned, I think the best approach may be to wait several days…and adding the heat wouldn’t hurt. I’ve used a brooder lamp hanging over it in the past with good results.

-- Our village hasn't lost it's idiot, he was elected to congress.

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distrbd

2227 posts in 1910 days


#9 posted 12-28-2015 02:44 PM

I have not done this myself but I have read that if your ratio is not correct (which makes your mixture not cure properly),you could pour a new layer of properly mixed epoxy over the old/tacky one and that is supposed to take care of the problem.
I always empty the two potions into a third container and mix the heck out of it until I start getting tiny bubbles floating in the air ,then pour it on the surface, use a heatgun to get rid of the bubbles.so far have not had any surprises.

-- Ken from Ontario, Canada

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Harry

71 posts in 643 days


#10 posted 12-28-2015 02:52 PM

I highly doubt this helps but years ago, I used a 3 part epoxy and forgot to add the 3rd (small tube, catalyst). What a serious mess!

-- Harry - Professional amateur

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MrUnix

4224 posts in 1662 days


#11 posted 12-28-2015 04:02 PM

How old was the epoxy. Most people don t realize it has a shelf life. And the obvious question, how long did you mix it?
- Tennessee

That’s the first time I’ve heard of two part epoxy having a shelf life unless improperly stored! System Three says ”All solvent-free epoxies have essentially unlimited shelf lives so long as they are stored in sealed containers.” (Ref: System Three FAQ) I have some West System epoxy that I bought maybe 10 years ago and it is still perfectly usable, although the hardener has turned a bit amber.

Proper mixing and cure temperature is important though.. and 60F is on the low side of what is acceptable unless using a hardener specific for lower temperature. Again, the System Three FAQ says:

My epoxy resin is taking too long to cure. How can I speed it up?

The only way to speed the cure of our epoxy resin products, once they’ve been applied, is to heat the room or the area that your project is in. Every 18°F increase in temperature cuts the time it takes for the resin to cure in half.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Tennessee

2410 posts in 1978 days


#12 posted 12-28-2015 05:51 PM

I agree it is a heck of a long shelf life as long as it is in sealed containers. I’ve heard stories of people having it last well over a decade. I think on one forum I saw where a representative of an epoxy company said they had tests going out 28 years and it still worked. Totally sealed containers, of course, and no crystallization of the resin. That can be reversed by heating, though.

But the hardener is what goes when it goes. Turns amber, then when bad turns a reddish amber. At that point, it loses the ability to cure. Not sure on the chemistry – something called a diamine.

-- Paul, Tennessee, http://www.tsunamiguitars.com

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