West Systems hardener will turn redish brown when exposed to moisture.
As per their website:
"PROBLEM: Hardener has turned red after several years storage.
POSSIBLE CAUSES & SOLUTIONS:
Moisture in contact with hardener and metal container.
Red color is a normal condition. It will not affect epoxy handling or
cured strength. Avoid using for clear coating or exposed areas where
color is not desired."
Been there, got that.
Hardeners are normally amines that darken with oxidation. Sometimes it
only takes a few parts per million to do this. Everything should still
work fine. Best to keep ingredients cool, dry and out of sunlight. I
have epoxies and hardeners in basement cabinet that I think are still
good after over 30 years storage.
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