Resin, Hardener Age

I’ve got a can of resin and tubes of hardener that are several years old. Should they be thrown out or are they OK to use? Which goes bad, or do both? The hardener tube is still sealed.

I've used older epoxy and polyester without problems. The hardener for epoxy may change color, but still works. I've also stored the chemicals in a boat over NY winters without losing effectiveness.

There was a thread about this a few years ago. As I recall, the info received from manufacturers, was that for all intents and purposes there is not a shelf life on resin and hardener, though the hardener might darken considerably.

I've used stuff that was at least 7 years old with no issue.

Alan

Before throwing it out.
Try a small amount, and see it hardens.
In my experience, old hardener and resin seem to kick over much faster, than new stuff.
I helped a friend glass a hull. He had West System epoxy. The old epoxy, kicked shortly after mixing. Luckily he had some newer stuff, that was just fine. I don't know how old the first batch was, but guessing 10 years.

Good luck.
I save old epoxy for small things, not glassing a hull.

Jim

Thanks Jim,
Seems like wise advice. Better to be safe, I reckon.

I also have some newer jar of clear gel coat sent to me by a manufacturer for a boat I traded away shortly after Canoecopia. If anyone needs it, let me know. No hardener, of course. Hate to see it go to waste. I guess it’s different than standard resin, which is what I need.

West system hardener does go bad eventually, or at least I had some that did. It was quite old, likely at least a dozen years at the time (could have been 15 or more?). I don't remember if it was the fast or slow. It was the last bit of a batch from a friend that he gave me. I tried it as a small patch on one boat. The hardener was very black and resin still looked fine. It took forever to set up and was still sort of soft months later. I didn't have much of it. I just pumped it all (the hardener, seemed to have some resin left over) into a metal can and let it sit. It did harden up, but took a while and was pretty ugly in color. I threw it away. This was probably ten years ago now (at least?).

Vinyl ester has a much shorter shelf life than polyester or epoxy.

I just yesterday mixed a 6 oz batch of 5 year old RAKA 127 resin and their 608 hardener.
Resin had some solids that precipitated out, I had warmed it and got everything back into solution.
Hardener was a medium amber color.
That batch was thickened with Cabosil, and by the time I finished mixing and applying it (wall repair, 38 ft RV) it was warming up in the tub.
I haven't yet checked it this morning, but I expect it kicked just fine...