Aviation Oxygen

[Chris H]

Maybe, but you throw the word medical in anything, the price gets unreasonable.  The important factor to keep in mind is that Aviation grade is meant to be inhaled. This is not the case with the welding grade gas.  Could welding O2 work OK?  Probably, but if I am filling a tank from my O2 bottle, it is mine, or my buddies.  Both of whom I would like to see doing well at the surface after a big dive, and any dive for that matter.  Cost may be more an issue if we were talking about several hundred dollars, but if a bottle of aviator's is $20, how much cheaper do you want it?  There is a very good chance that all of the O2 in all of the bottles comes from the same source, however, the way the bottles are handled to ensure you are getting something breathable is worth the few extra dollars.  I’m sure there are plenty of divers breathing the welding grade gas.  You need to decide what is best for you and your friends.