I just wanted to tell everyone about my experiences with the long-term storage of polyester and polyurethane resins.

I bought a gallon of polyester resin in Sept 2000 and now it is semi-polymerized gunk which won't catalyze at all. I talked to a chemist about it and it seems that it polymerizes slowly just sitting in it's tin container. The lesson I learned? Don't buy a lot of resin if you aren't going to use it all. In fact I should have made a ton of parts from what I had when the resin was still relatively fresh.

Now the polyurethane resin is actually starting to crystalize, but it will still basically do it's thing. I bought it a few months ago, and I think I'm getting close to the point where it will stop working. I doubt very much if it will work after a year.

Don't buy more of this stuff than you need, you can always buy more resin later. I thought the polyester resin would last a long time, but after a year and a half it's molasses.