On Wednesday, February 24, 2021 at 5:19:34 AM UTC-8, Tango Whisky wrote:
The point is that with welding oxygen, there is no tracability that a an empty storage cylinder hasn't been left open which would enable moisture to enter. At 30 °C in a dry climate that would be 10 g/m3 water content. Take that content to -10°C and would freeze you valve solid shut (without even to take into account expansion cooling).
On the medical cylinders we use in Switzerland, we have a small valve inserted into the valvo of the cylinder which shuts of the cylinders below a pressure of 5 bars.
Le mercredi 24 février 2021 Ã* 10:03:46 UTC+1, Darryl Ramm a écrit :
On Tuesday, February 23, 2021 at 9:47:53 PM UTC-8, wrote:
At the Cowley wave camps, there's the odd day when record attempts are made to 30,000+ It gets really cold up there as in -30C - actually surface temperature at night a week or so ago.

My welding supplier advises ABO for that kind of height and temperature, and I'm inclined to believe him. But the turnaround time for ABO cylinders is really slow here.
Your welding supplier is confused. **there is no difference** This is the perennial noise that comes up on r.a.s every few years. All the O2 in these uses comes from cryogenic fractional distillation. The cyrogenic process freezes out all moisture. All those cylinders are filled from the same liquid oxygen source. Oxygen distribution systems are inherently dry. If they had moisture in them we'd have a boat load of safety issues in handling and distribution.


Thanks for all the responses. I only have room for one oxygen bottle in my Phoenix motor glider. Last year my trips were several weeks long with no well-planned destinations. Many days were spent with hours above 12 k. I had days where I had to motor, keeping below 10 k just to get more oxygen.
To add to the problem is not having ground transportation after landing to get to a welding shop. Last year while flying past Salt Lake City I talked to another glider pilot on the radio that told me oxygen was only available to club members at Nephi. I ended up landing at Provo to get a refill only to be told later that oxygen service was $140. They are used to supplying business jets. I talked to the manager who only charged me $40.
Haven't been to Moriarity yet but good to know they have oxygen. Hoping to find more airports with it.