What's the shelf life, and is my older/unopened product still usable?

Shelf life is on the product's TDS and varies by chemistry, many systems are rated roughly 6–12 months from opening, and longer if the container is still factory-sealed. Aerosol releases and epoxies have their own ratings.

• Unopened product stored cool, dry, and sealed often performs past its nominal date, but it's not guaranteed, the date is a quality assurance window, not a hard expiry.
• The real test: mix a small test batch and see if it cures correctly. If a test patch cures to full hardness in the expected time, the batch is good for your work.
• Storage matters more than age: keep containers tightly closed; moisture-cure and urethane components degrade fastest once air/humidity gets in. Crystallized or separated parts can sometimes be gently warmed and remixed, check the TDS.

Learning CenterFull guide: Materials Shelf Life Warranty · Storage Considerations