Epoxy chemistry

I’ve got this old epoxy on the shelf with tons of white crystals at the bottom of the can. There are big chunks of it, but it does not seem to affect the epoxy much. If I mix up a small batch of it(crystal chunks and all) it seems to go off as normal. Anyone had something like that happen or know what’s going on(Greg?)?

Just for the record, I don’t plan to use the resin for any lamination. Just curious.

regards,

Håvard

Hello Haavard, I am not an expert but I notice that our epoxy catalyst turns into white crystals also. I think that this means it has oxidised and so it probably won’t be quite as effective as a catalyst but if it works there shouldn’t be a problem. Roy

Haavard,

I seem to remember coming across something about this in the archives, or possibly one of the epoxy suppliers’ info packets, (maybe west systems “epoxy book”) and I think the jist was that gentle heat would enable the crystals to dissolve again, much like a jar of honey. If I remember correctly, it’s not any kind of chemical change or degradation, just crystallization of the epoxy. Better wait for more definitive word than mine however…The impression I got was that epoxy has a pretty long shelf life…

wells

Hi Roy,

I guess I could me a little more clear, it’s not the hardener that has crystals in it but the base. The hardener turns awfully yellow if it’s in contact with air, but no crystals. And it still works too…

regards,

Håvard