"Shelf Life"

[rxckitralph]

Is there a shelf life on propellant grains? Specifically kno3 and sorbitol/sugar?

 

[cwbullet]

That depends on the shelf. It is very moisture sensitive. I have made a few sugar motors. I have never stored them for more than 90 days. I think it could last months to a year if you store them in a cool environment and prevent moisture or high humidity. I put mine in a vacuum bag and in an ammo can.

Does anyone else store them longer?

 

[Antares JS]

Aside from what Chuck mentioned, the other issue with sugar grains is their brittleness, which makes them prone to cracking. If you don't know how the grains were handled in the past, I would advise against attempting to use them.