[Christ]

Originally Posted by jamesqf

Yet welding oxygen is stored in non-exotic metal cylinders, and is not all that expensive - something like $25 to refill a cylinder, IIRC.

Yeah, it's about $25... and welding grade O2 isn't pure oxygen, either. I don't remember if they actually add anything to it, but it's not even close (relative to terminology) to medical grade (pure, for all intents and purposes) oxygen supplies, which are stored in plain old aluminum tanks that have been vacuumed and boiled (heated to just over 100*C) prior to filling.

The problem doesn't rest with O2 being reactive to metals as a whole, it comes with O2 reacting pre-combustion with other elements in the combustion chamber, such as nitrogen and what not in the air. Pure oxygen is in fact an oxidizer, but the maintained reason for the nitrous in nitrous oxide is stability of the gas itself.