Do epoxy resins/hardeners have a shelf life? Confused, help!

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#1

ello,

I have tried overlaying some interior parts from a car. I have 2 yards of CF and already had to remove the cloth from the part because it appears that the epoxy hasn’t fully dried. So i waste that cf portion and re-cut another pc. to try again. I am using some US composites thin 3:1 epoxy, with pumps. So i pump 3 parts epoxy to 1 part hardener. I timed how long i mixed for, which was about 5 minutes straight to ensure that it was mixed thoroughly. I work with fiberglass almost every day working on cars, but am new to this CF thing. Well it’s been about 40 hrs and is still somewhat tacky, but not to the point where it’s dripping or anything. Should it be completely hard by now or does epoxy take forever to dry? I’ve been trying to maintain about 80 degrees in my basement. Should i go with west systems epoxy? I’ve had this resin/hardener for about 1 yr. Anyways any feedback would be appreciated. Thanks

C

#2

In my class, we don’t get to use Epoxy much…but last year I did buy 5 gallons of Hawaiian for VIP, but we never got around to using it.

This winter I had to use a little for something and it was like Karo sryup!

Well, this week I was working (on my Spring break no less…) an over sized PUR foam sheeting, knock down oven for TP strech / gravity blow molding or larger scale Pre-preg than our little classroom oven can do…:rolleyes:

I use some at 7ish, cooler and I took off to make a couple of deliveries thinking since it was 15 minute pot life…got back after maybe 2 hours and it was still liquid! Bummed…got to go home…

But the next day it was fully cured. I then mixed up another batch (same %'s of 2 to 1) but it was warmer in the day…and after 3x of the 4x items I was using it to glue together, it got smoking!

Go figure…

Try a warmer and dryer location?

Test on small test pieces first???

#3

Thanks for responding,

I actually mixed up some epoxy and let it sit thinking it was gonna cure. Well it gel’d up but never got completely hard. I then took it out to the deck where the sun was hitting down on it, a good 88 degrees. It became VERY soft, and expanded and got syrup-like. Is this normal? Now that i think of it… i had the resin jug laying sideways in a box with the pump still on. Could there be a possibility that there is buildup inside the pump, clogging up the passageway so the resin mixture wasn’t proper?

What is the best/most inexpensive EPOXY you would recommend because i’m ready to buy more ASAP. This part would have came out awesome with the weave being very uniform and hugging the curves very tightly. I see myself getting addicted to this. I’m currently using the U.S. composites and i don’t think i wanna mess with it again if i’ve had to redo 2 parts. Thanks

C

#4

The pump could have a restriction in it…maybe try a couple of measuring type cups for your 3 to 1 % and see what happens?

We get some great cups Made by Solo cups in Chicago) from Delvies in Salt Lake, Utah that have all sorts of measurements on them (800) 533-5843.

On Epoxy, I would suggest something close to you to save you shipping costs…