Does polyester resin go "stale"?

[dward51]

I have a gallon of Evercoat marine grade polyester resin and their premium hardner I got at West Marine quite a few years back for a repair on a boat. I got rid of the boat before do the repairs, and ran across the resin in the basement the other day. It's never been opened, nor has the hardner and if I "slosh" it around, it sounds like I remember when it was new. Does this stuff have a shelf life or would it be good to use for any projects?

Don't have a project in mine yet, but if it might still be usable I'll hang on to it instead of sending it to the landfill.

[BASSCAT7]

Resin does have a shelf life but many variables will affect it, temp, sunlight, humidity, storage container. What has a shorter shelf life is the Catalyst, the MEKP.
Usually after a few years the resin will start to gel, then it is no good to use.

If it is unopened and stored in a cool ,dark place and sounds like it did when you purchased it, you probably could use it, but test a small batch first before use to see if it will catalyze correctly.

[dward51]

Ok, and I'll get a new tube of MEKP also. I figured the resin might still be good.