So this is a bit of a strange one only because I never thought about it until now.
Unlike super glue, which I refrigerate and replace every year with a new bottle regardless, definite shelf life to super glues. Definitely a point where it no longer has its adhesive qualities.
But Testors red tubes for me goes in the same category as like Vallejo paints, Contrast paints, Foundry paints, etc. They all seem to last "indefinitely" as long as they are closed between use and have a good seal.
I've kept my Testors in a zip loc bag that's sealed. I've got three tubes that are from the 2018-2020 time period, the oldest 2018 tube still works fine, none of them ever went hard or separated.
So my question is, if Testors is still in usable consistency, it doesn't seem to "expire"? I mean, it doesn't stop "working" perse. It's either good or it hardens and becomes unusable. It's never appeared to be normal and suddenly wouldn't bind two plastic parts is what I mean.
I suppose if it's left out and not put in zip locs it would harden faster.
Not that it's expensive to buy! But I kind of just kept using the same tubes and they are still going strong.
shows how to build a structure from common materials.