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Oct 21, 2017, 11:18 AM
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Discussion

Epoxy


Recently had issue with epoxy not curing. Any suggestions? Been building for 50+ years so not looking for answers such as not mixed properly Thanks in advance.
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Oct 21, 2017, 01:04 PM
Dinosaur
Twodor's Avatar
Quote:
Originally Posted by GSAV8R
Recently had issue with epoxy not curing. Any suggestions? Been building for 50+ years so not looking for answers such as not mixed properly Thanks in advance.

Too cold in your shop or...maybe you did what I'll admit to doing a couple of times over the years. Mix your epoxy using part 'A' twice?

Tom
Oct 21, 2017, 02:06 PM
Registered User
Maybe it was too coll. Thanks!





Quote:
Originally Posted by Twodor
Too cold in your shop or...maybe you did what I'll admit to doing a couple of times over the years. Mix your epoxy using part 'A' twice?

Tom
Oct 21, 2017, 02:59 PM
AMA 46133
Quote:
Originally Posted by GSAV8R
Recently had issue with epoxy not curing. Any suggestions? Been building for 50+ years so not looking for answers such as not mixed properly Thanks in advance.
I also think it is too cold in your workshop. I think if you are anywhere below 60F it may not cure, at least for a long time. How old is the epoxy? Never mind, I actually have over 30 year old epoxy that cured fine. Still using them.
Oct 22, 2017, 08:43 AM
ARFs Are Me
TomCrump's Avatar
When I worked in an auto plant, we had a saying about questionable parts. "When in doubt, toss it out" I think that it applies to your situation.
Oct 23, 2017, 04:38 PM
Registered User
There are only 3 reasons why epoxy may not fully cure.

1. Improper ratios
2. Not mixed well enough
3. Too cold.

If the initial cure was done in too cold of an environment, it will eventually set up. A heat gun a few times a day will greatly speed that up. If with the application of heat over a couple days does not make a difference then as much as you don't want to hear it, it has been mixed in the wrong ratio or not mixed well enough.
Oct 23, 2017, 05:11 PM
San Antonio TX.
sensei's Avatar
Quote:
Originally Posted by EXF3BMAN
There are only 3 reasons why epoxy may not fully cure.

1. Improper ratios
2. Not mixed well enough
3. Too cold.

If the initial cure was done in too cold of an environment, it will eventually set up. A heat gun a few times a day will greatly speed that up. If with the application of heat over a couple days does not make a difference then as much as you don't want to hear it, it has been mixed in the wrong ratio or not mixed well enough.
Who likes epoxy anyway.

Bob
Oct 23, 2017, 07:50 PM
Registered User
LOL Bob, in the last 7 days I have been part of a process that has dispensed over 200 gallons of mixed epoxy resin. I should hate working with the stuff but just ordered enough to glass this fuselage and produce a set of molds from it.
Oct 23, 2017, 10:14 PM
San Antonio TX.
sensei's Avatar
That thing looks awesome buddy.

Bob
Oct 23, 2017, 10:25 PM
Registered User
tailskid2's Avatar
Try putting the part(s) in your car and with the windows up, let it sit in the sunshine for a day or two. Had to do that a couple of times when I lived in Fort Wayne, Indiana.
Oct 23, 2017, 10:37 PM
Registered User
Quote:
Originally Posted by sensei
That thing looks awesome buddy.

Bob
Thanks Bob, it's something I have been designing in my head for a while and finally decided to make it a reality.
Oct 23, 2017, 10:37 PM
Registered User
Quote:
Originally Posted by tailskid2
Try putting the part(s) in your car and with the windows up, let it sit in the sunshine for a day or two. Had to do that a couple of times when I lived in Fort Wayne, Indiana.

A great way to expose epoxy to an elevated temp.
Oct 31, 2017, 02:06 PM
Registered User
What sort of epoxy resin was it (brand and version)? Laminating or adhesive? Ive had trouble with some resins where i needed to stir up the resin because it was old and started to separate before mixing in the hardner. I also use heating blankets to control the cure rate more easily. Ive also had trouble when Ive mixed small batches but that's been more the case with tooling resin.
Oct 31, 2017, 08:51 PM
Registered User
Any chance the epoxy is great planes brand? I had the same issue about a year-ish ago and learned a bad batch got out. I tossed it and switched to Devcon and no problems since.
Nov 01, 2017, 03:35 AM
Registered User
I buy in larger quanties and have no problem as long as you weigh it, i use a 5 to 1 mix, so 20 gram, epoxy 4 gram hardener etc. and keep it warm when you are using it.


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