Oxygen types?

[panther1400]

If a person is looking to fill his own oxygen what do you guys recommend, medical, aviators or welding?

[DonMuncy]

They all come from the same source. Buy whichever one is cheapest; ie. welding. However, the welding guys don't like liability, so I would not mention what I was getting it for.

[kris_adams]

Yep, it's all the same.  I was able to fill my bottles for $15/each at the local airport.  I searched all over looking for cheap alternatives and then finally called the local airport and was surprised.  I got "aviation" oxygen but as Don points out, it's all the same anyway.  Good luck!

[Antoni Deighton]

Becareful with the moisture content of the oxygen you buy. Aviation oxygen is very dry so it doesn't freeze in the lines. While this may be unlikely if you're just slinging a bottle over a seat back (you'll know if it's cold enough to freeze) it may not be so easy to tell with a built-in system. Medical oxygen is wetter to prevent drying out of the internal tissues since it tends to be used over a much longer period. (It's cheaper too, because of the quantities consumed.)

[David Mazer]

Antoni is correct.  Oxygen isn't all the same and the humidity content is the difference.  Aviation oxygen is more expensive unless the FAA catches you.  I have been told, but fortunately don't know from first hand experience, that the fine for using non-aviation oxygen is about $10,000 per occurrence.  Sounds steep but since everyone in the plane is dependent on staying alive on the stuff and you won't know it until you are already in danger, maybe they have a point.

[DonMuncy]

With due respect, the O2 today is all from the same maufacturing facilities. At one time they may have treated medical, aviation and welding O2 differently, but not now. Medical O2 has to have water added to it to keep if from drying out the patient's respiratory passages.

[Ellioth]

...and the water is added to the line in the patient's room, not at the O2 tank

[Jerry 5TJ]

Yes, you can get your O2 bottle filled at the scuba or welding shop, but make sure they put in 100% O2 and not air or Nitrox.   No, that's not a joke -- I recall at least one accident report where the NTSB found the aircraft's O2 bottle contained 21% oxygen, to wit, compressed air.    Here's one:  NTSB  report   IAD97FA060.

[sbethune]

 

 Aeromedix' Dr. Brent Blue -

Since the 1960s, all oxygen sources have been from liquid oxygen. There is no difference between aviator’s and medical oxygen. When oxygen was first used in hospitals, the gas was humidified in the tank which is a problem for aviation because water will freeze in oxygen plumbing in cold, high altitude aircraft environments. Since medical oxygen is humidified after it leaves the tanks, this is no longer an issue. However, getting something taken off the FAA regulation books requires undue time and energy so everyone uses whatever oxygen they can find and no one apparently cares. If you truly get “aviation” oxygen, you will find the only difference is that it is tested for water and is more expensive.

http://www.aeromedix.com/blog/2008/11/oxygen-for-general-aviation/

Your motor may run well lean of peak, but your brain doesn't.

[kris_adams]

Quote: Ellioth

...and the water is added to the line in the patient's room, not at the O2 tank

[danb35]

Mazerbase, what you've been told about the fine for using the wrong type of O2 is also incorrect. There's no regulatory requirement that a private operator use aviator's (as opposed to medical or welding) O2, and no fine for doing otherwise. 

[panther1400]

Thanks for all the replies I went with a 251cu ft tank and bought one through Thoroughbred (www.gaspony.com) and the refill is $28.  I still need the transfil but I think I will call Aerox this week and get that ordered.

[David Mazer]

It's always comforting to learn everything I thought I knew about a subject was wrong, again!  Someday I'll learn to listen more and speak less.