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General control line discussion => Open Forum => Topic started by: Fred Quedenfeld jr on November 15, 2019, 10:29:51 AM
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which epoxy gives the best shelf life
I got 4 year old T-88 from system 3 hard
I got 2 year old unopened from cj composite hard
I got 20 year old epon 815 w teta hardner but it only hardens with heat
Does West systems last 5 or more years???
Fred Q
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I've had System 3 epoxy that I had for what seemed like forever that still cured without problem. But like they say about the stock market, past experience is not necessarily indicative of future performance.
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I have found that epoxy resins crystallize and harden with age but can easily be re-liquified by setting the container in boiling water.
The hardening agent can be another story. They generally seem to have a more finite shelf life but I do have some hardeners that are several years old that still work.
Some people have used a microwave to heat the resin but I have always been leery of overheating using that method.
In summary you have nothing to lose by trying this.
Good luck.
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My work shop is heated only when I'm working there. The Bob Smith epoxy is pretty cold all winter. 10 seconds in the microwave gets it warmed up just enough for easy pour and mix. The nuking process doesn't harm the cure.
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I have used west systems epoxy that was more than 5 years old, kept in an attached but not climate controlled garage. The hardener turned red orange and the base crystalized, but putting the cans (both) into hot water for a time made it useable. Hot tap water, well over an hour. It seemed to cure properly, but the color was off.
https://www.westsystem.com/instruction-2/
Phil
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I used 5+ yr leftover T88 structural epoxy (1:1) that worked fine on small projects. I'm sure it lost some strength but otherwise I couldn't tell the difference from new. I did a comparison with the old T88 and new WEST G4 by pouring solid ice cube size samples. After a couple days I smashed them with a hammer to see what would happen...the G4 easily broke to pieces and I had to beat the hexx out the T88 to break it. I also had 10+ yr old Reichhold 5:1 epoxy that hardened like new in some test samples but I never used it on anything because it was so old. If you pay attention to the mfgs they say a couple yrs is the shelf life.
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I moved to Williamsburg, VA in 2009. At that time I had epoxy resins and hardeners which had been with me in my shop in PA for perhaps 20 years! I am still using all of what's left with absolutely no malfunctions! I do tend to use the obvious younger ones in more "important" applications but nothing has left me down as yet!
Phil Spillman
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There are so many different flavors of epoxy that you can't generalize much. But generally, if the two components will melt when heated in hot water(if they have thickened or gotten hard) they will work.
If you can't get it thin enough to mix uniformly before it starts to cure(5min, 30 min, 1hr, etc.) throw it out.