Hey repair guys.... does methyl ethyl ketone peroxide (polyester resin hardner) go bad? Shelf life? I have a bottle of it that's at least 3 years old. Used some the other day and it took the batch of resin forever to cure. Temps and ratio's and all else were okay.
Depends...sunlight is a sure killer (but most of the stuff you/we buy in a ding repair kit usually is usually in an opaque container). I have stuff that was a year+ not go bad...never had it much longer than that...here is some food for thought...http://www.fiberglassforums.com/misc-fabrication/6942-mekp-hardener-shelf-life.html.
MEKP does have a "shelf life." But as it's already been said, proper storage will extend that life considerably. Sunlight will basically kill the stuff. But tightly sealed in a plastic container, and stored in a cool dark place, will let the stuff last for years. I've used cat that's 5 years old and it worked fine... but I pay attention to how it's stored. It's kinda late now, but you should do a test batch if you're not sure. Keep in mind also that different resins require different amounts of catalyst. There are differences between brands, and between types of resin... namely, gloss resin takes longer to kick than lam resin, and pigmented or tinted resin takes longer than clear.
