On Monday, May 7, 2012 2:11:21 PM UTC-5, Bill D wrote:
On May 7, 12:42*pm, wrote:
On Monday, May 7, 2012 12:08:34 PM UTC-5, Dan Marotta wrote:
Wasn't it P.T. Barnum who said, "There's a sucker born every minute"?

ABO - *Hah! *I only had one year of chemistry in college, but I do recall
that an element is an element is an element. *Oxygen is oxygen.

"Bill D" wrote in message
....
On May 5, 10:06 am, bumper wrote:
If the tank is "portable", and you will be having it hydro tested
locally, I suggest NOT using a welding supply place unless they test
on-site. If they throw a bunch of bottles in a truck to send off for
testing, your nice bottle will not come back looking the same.

bumper

Yep, welding supply shops can be tricky.

Once I was on a errand to pick up a refilled (large type) O2 bottle.
While I waited for my turn at the counter, I noticed a truck being
unloaded at the dock. It was loaded with green O2 bottles - none of
which showed the blue "Aviation Oxygen" sticker.

Since I couldn't see any Aviation Oxygen bottles, I told the
counterman I wouldn't be surprised if he couldn't fill my order. *"No
problem", he said, "Watch". *He opened a drawer, retrieved a sheet of
blue Aviation Oxygen stickers and slapped one on the nearest green
bottle. *"Now, he said, "I can sell you an Aviation Oxygen bottle -
that will be $115." *"How much would it be without the sticker?"
"$35", he said.

It's surprising how honest people can be at times.

... Oxygen is oxygen.

I was just studying with my 2012 Private Pilot Test Prep book and found a relevant and hopefully interesting passage:

"Aviation oxygen should be used to replenish an aircraft oxygen systems.... Oxygen used for medical purposes or welding normally should not be used because it may contain too much water. *Specifications for Aviators' breathing oxygen are 99.5% pure oxygen and not more than .005 mg of water per liter of oxygen."

That information was true 100 years ago but it's about a century out
of date. Oxygen today is made from a liquid air reduction process
which produces chemically pure oxygen. This is what is supplied to
all users. There's no incentive for the industry to deliberately
produce contaminated oxygen. There is zero water in any compressed
oxygen sold today.

If you dig a bit further, you'll find specifications for welding and
medical oxygen are far tighter than for 'aviation oxygen'.

Well, I guess the source of at least some of the obviously widespread confusion is clear - our training materials are incorrect and/or just out of date and out of touch with technical reality. thanks.