Best before date on CO2 cylinders?
 

How long can you have a filled and tested CO2 cylinder sitting around before issues (if any) are likely to arise or can it stay like that indefinitely?

only issue is that they need to be hydrostatically tested every 5 years. there should be a date stamp near the top of the tank. if the date is past due, no one will fill it till it's re-tested. test is about $20 i think.

Hydrostatic Testing
 

Aluminum & Steel Cylinders require Hydrostatic testing every 5 years, Fiber Glass Composite Cylinders require testing every 3 years, Carbon Composite cylinders require testing every 5 years. Make sure if you purchase cylinders from the US, that they have a TC (Transport Canada) stamp and number on the cylinder as well as a DOT (Department Of Transport) stamp and number. If your cylinder is newer than 1993 and does not have a TC stamp it cannot be hydrotested in Canada. The best place in Edmonton to get your cylinders Hydro Tested is Atlas Fire & Safety Equipment Ltd.

Cheers

Has anyone ever painted their CO2 canister? It says on top..."Do not modify in any way"..I don't know if that includes paint.

Mine is raw aluminum and since it is close to the tank it tends to get oxidized by the salty air, making it really unpleasant to handle.

mine is painted also, scuba cylinders and fire extinguishers are regularly painted with no problems