mark poulson Posted June 17, 2019 Report Share Posted June 17, 2019 There have been a lot of threads about how long unmixed epoxy lasts, before "goes bad", and I think this may help answer that question. I just completed one have of a two part POP mold, and wanted to seal it with epoxy before I poured the second part. I had some Etex up on a shelf in my garage that was more than ten years old. It has been through temps from low 30's to 100's over the years. I haven't used it in at least five years, but I decided to see if it was still good. The catalyst was still liquid, but the resin had turned solid for the most part. There was still a bit of liquid resin left, so I drained it into a salsa cup, added the same volume of the catalyst, mixed it very thoroughly, and then added another 25% denatured alcohol to thin it. I brushed the mix onto the dried/cured POP mold half, wetting it completely, and left it to cure overnight. When I checked it this morning it had cured out hard, clear, and shiny, and I'm going to go down this afternoon and pour the second half ove the mold. I had to chuck the resin bottle, since all that was left was hardened resin, but it showed me that, as long as the resin is liquid, it is good to use, at least for sealing POP. Quote Link to comment Share on other sites More sharing options...
JimP Posted June 17, 2019 Report Share Posted June 17, 2019 Mark, Too bad you pitched the hardened portion, I have read about but never actually tried this. The hardened material in the bottle can be returned to liquid state just by warming the bottle in warm water. At that point it should be good to go for another extended time period. Has anyone done this? 1 Quote Link to comment Share on other sites More sharing options...
mark poulson Posted June 19, 2019 Author Report Share Posted June 19, 2019 On 6/17/2019 at 4:22 PM, JimP said: Mark, Too bad you pitched the hardened portion, I have read about but never actually tried this. The hardened material in the bottle can be returned to liquid state just by warming the bottle in warm water. At that point it should be good to go for another extended time period. Has anyone done this? Jim, After reading what you said, I fished the hardened resin bottle out of the recycling, which had been out in the 90 degree heat. Lo and behold, it was liquid again. Solar heating! So I now have half a bottle of E tex resin to go with the half bottle of catalyst that was still good. Thank you. Quote Link to comment Share on other sites More sharing options...
JimP Posted June 19, 2019 Report Share Posted June 19, 2019 Good deal! Thanks for the reply, now we all know that warming the ETex will return it to a usable form. 1 Quote Link to comment Share on other sites More sharing options...
dv616 Posted June 19, 2019 Report Share Posted June 19, 2019 Epoxy can crystalize and warming it does return it to usable condition. I find that with old rod building epoxies since the epoxies sit awhile between uses. 1 Quote Link to comment Share on other sites More sharing options...
SlowFISH Posted June 19, 2019 Report Share Posted June 19, 2019 I think the "expiration" on alot of these curable resins is based on tow factors - 1 - how well it performs - which I could see some drop off over time - but for many many many things isn't a big deal and the second - suppliers wanting to sell product. I needed to reinforce something and wanted to use fiberglass to back the repair... found two quarts of epoxy resin in my shed which had to be atleast 4-5 years old - if not more... last time I can remember making something with it I lived in another house which was 4 years ago!!! It worked just fine... granted I probably wouldn't have used it for a structural application where you could hurt someone - but for what I needed it worked fine.... J. 1 Quote Link to comment Share on other sites More sharing options...
