a good reference is the oxygen hacker from airspeed press.
the air grade is super dry air to prevent o2 line freezing from moisture in the gas on planes that have o2 lines on the skin of the plane. > 80% o2
med o2 is i think > 80% o2 and when filled the bottle is vacumm empty then filled to insure no contaminates.
welding o2 is 99.x% o2
all the gas comes out of the same storage tank. the filler may do some filtering on some of the lines for some of the fills.
the reall difference is the price.
med o2 $$$$$ needs a perscription to get
avation o2 $$ probably have to get at an airport
welding o2 - well 20 bucks for a tank refill from a gas supplier
i have no problem using welding o2.
i will soon make my own o2 from a concentrator and pump it into a 2200psi o2 tank
He uses welding o2. The better question might be, "what do you use and why."
I have only rented tanks once. I went for the ultra high purity HE and welding O2. I did have an account at the place and was a weekly buyer of propane for forklifts so no questions were asked to a familiar face.
-matt
Last edited: