Epoxy question

[Tooeez]

I have some leftover West System epoxy that is about 4 years old. The hardner has turned a brown color, but when mixed it seems to cure OK. Does anyone know if this effects the strength of the epoxy?

[Stephan]

I believe it does not degrade. I have had some similarly old West System and though it mixed to a light amber color (I believe only the hardener was darkened) it worked.
I hate having to make the call to throw out some expensive materials for fear of spoiling the job.
Good luck-

[Marlin]

Too much of a risk for all the prep work u go thru to get to this point. I used some west product that had frozen over the winter, it's still not cured, the catalytic reaction of the hardener changed!

[Stephan]

I used some west product that had frozen over the winter, it's still not cured, the catalytic reaction of the hardener changed!

I believe I have had hardener and epoxy get below 10 deg. It got molasses thick but never a solid. Warmed back up to room temp it worked for me. Sorry you had that experience. Any other events that might have impacted it? I have had the plastic pumps that West sells fail and give me the wrong proportions.

Tooeez- After re-reading your question I realized I always end up with some extra epoxy after mixing a batch. I 'm in the habit of spreading some on some wax paper (poor man's release paper) and if in a disposable pot let it stand to see how it cures. I check those bits for confirmation that the cure kicked properly.

Best,
Stephan

[Tooeez]

Thanks for the input everybody. Stephan, I always leave a little to cure in the mixing cup just to be sure it sets. This brown mixture seems to cure OK, but I am going to be closing up a through hull and I am concerned if the strength is affected in any way. It would make for a bad day if the patch I make decides to let go someday . . . .