metalman;11507 said:I was told by a poly resin manufacturer to keep tubes of MEKP hardener stored away from light to keep it from going bad. This was after I had a problem with resin not hardening.
I don't know the science behind their recomendation but it is easy to put the tubes of MEKP in a box in a cabinet out of any light for storage.
It is unfortunate that you discover the problems only after applied to the work .
YES and YES, ALSO, if the package is a plastic container I would date it and never use one over a year old.