On Jul 12, 7:51*pm, ContestID67 wrote:
Go to your local welding supplier. *The oxygen is just the same as you
get from an FBO and a fraction of the price.

Andy

I don't believe that it can be welders oxygen. *It can't even be
medical oxygen. *It must be "Gaseous aviator’s breathing" (AVB)
oxygen. *I read it has to do with the moisture content to prevent
freezing. *True?

It there an FAA regulation on this? *I can't find it.

Some info herehttp://www.faa.gov/pilots/safety/pilotsafetybrochures/media/Oxygen_Eq....

As Bill states, this is completely wrong. Its an old wives tale that
has been repeated here before and I've tried to shoot it down then as
well. I have some background in low-temperature physics/cryogenics
research so let me play whack-a-mole with this.

Oxygen is manufactured by fractional distillation of liquid air (the
Linde process). This generates highly pure oxygen. This produces an
inherently dry gas product. The same liquid oxygen is boiled off and
packaged as compressed oxygen for welding, aviation, medical, other
industrial and scientific applications. All the handling system for
these cryogenic liquids and gasses are very very clean for saftey
reasons.

None, nada, zilch of these end-use gasses have moisture added to them.
Compressed oxygen is a dangerous oxidizer. You would be beyond insane
to want to introduce moisture and resultant corrosion problems to a
compressed oxygen storage system. And under high pressure the moisture
would condense out. Expensive compressors and other equipment would be
damaged by this liquid condensation. Adiabatic cooling as the gas is
release through valves and regulators would cause condensation--if
there was moisture in aviators breathing oxygen regulators and flow
meters etc. could freeze up at cold temperatures found at altitude. It
just makes absolutely no sense to imagine any addition of moisture to
the compressed gas for any purpose. What seems to be the source of
this confusion is medical applications where water is vaporized and
added to the dry gas or the dry gas is bubbled through water etc. at
delivery time--all done at very low pressure.

So can we bury this one please?

Darryl