What to do with propane canisters

[Brass]

Mark, if 20-lb bottle propane is not dried, how do they keep those containers from rusting?

[MarkCO]

Mark, if 20-lb bottle propane is not dried, how do they keep those containers from rusting?

20 pounders are filled from a bulk tank, which is dried propane. BUT, there is a test and re-test requirement on tanks. That process (stamped tare weights, inspection, etc.) catches those tanks with internal corrosion. It also catches those tanks used for ammonia, or other oxidizers used in illegal drug manufacturing process.

[Brass]

So, if the 20s are filled with dried propane, wouldn't you be refilling 1s with dried propane from the 20s? I can't imagine how the dry propane would get "wet" when transferred into 1-lb cans except for that little bit of air in the transfer tube the first time you use it.

PS: I'm not arguing with you, I just can't figure out the source of moisture infiltration.

[MarkCO]

The walls on the 1# are extremely thin as compared to the 20#. There is no factor of safety for propane in the 1#s.