refilling O2 bottles on the road.

On Saturday, June 2, 2018 at 9:52:46 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
Find a medical supply house?
Also look for SCUBA shops, industrial gas suppliers (like AGL) but be forewarned, they may do O2, make sure they can do BREATHABLE O2.

Maybe call some local to you places, explain what you're looking for and why, see what they say.

Can you give an example of unbreathable O2 and who supplies it?

No, I can't.
I go based on having Scott airpacks refilled for emergency use at manufacturing plants I have worked at in the past.
User manuals back then stated to refill with "breathing oxygen", thus my comment.
I thought part of that was humidity, but not sure.

If someone went to a decent supplier and asked for "breathing oxygen" and were told, "no difference", then fine.

On Sunday, June 3, 2018 at 7:25:01 PM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
No, I can't.
I go based on having Scott airpacks refilled for emergency use at manufacturing plants I have worked at in the past.
User manuals back then stated to refill with "breathing oxygen", thus my comment.
I thought part of that was humidity, but not sure.

If someone went to a decent supplier and asked for "breathing oxygen" and were told, "no difference", then fine.

Moisture differences in different labeled oxygen supplies (again we are talking about O2 from cryogenic fractional liquid distillation) is an old wives tale. There is no water vapor in the gases produced by fractional liquid distillation, and nobody is going to add any downstream to the high pressure gas. High pressure O2 is extremely reactive and the systems would not tolerate moisture in it. Imagine the rust/corrosion eating holes inside a steel cylinder in a pure oxygen high pressure environment with water condensed inside of it. Yes they nay have surface treatment, but its only partially effective. Humidity in medical oxygen is added to the oxygen at the point of administration when the oxygen is essentially at room pressure and the delivery system is all inert plastic and silicone.

There are risks in dealign with this stuff. Handling any high-pressure gas and such a powerful oxidizer as high-pressure oxygen is dangerous, I hope people minimize those risks, there have been had fires during transfilling and nice articles about that in Soaring Magazine in the past, luckily nobody was injured or killed. Personally I'm OK with breathing welding supply oxygen as long as I know the handlign has been reasonable. I have been more worried just seeing people handle cylinders with less than respect than they deserve.

So what happens if I rent a welding cylinder, weld until it's empty, remove the regulator, forget to close the valve, and just for fun it gets rained on?

Do they just refill it or dry and purge it first?

On Sunday, June 3, 2018 at 9:14:57 PM UTC-7, wrote:
So what happens if I rent a welding cylinder, weld until it's empty, remove the regulator, forget to close the valve, and just for fun it gets rained on?

Do they just refill it or dry and purge it first?

If folks who rely on that cylinder find out the back of you head might hurt :-)

I would ask your specific supplier. Many places will get more cautions with cylinders that have no pressure in them, simple purging at a minimum. if the cylinder was suspected of containing water the fill station can fully dry it and if they want wan to internally inspect it or fully test it. Remember the cylinders are fully wet internally when hydrotested... but they are dried and purged before refilling.

If you abuse a cylinder and it causes serious internal damage I hope that is found in time by the next cylinder test, in the internal or ultrasound inspection or pressure test.

On Sunday, June 3, 2018 at 9:14:57 PM UTC-7, wrote:
So what happens if I rent a welding cylinder, weld until it's empty, remove the regulator, forget to close the valve, and just for fun it gets rained on?

Do they just refill it or dry and purge it first?

My experience is that it varies. But I have had suppliers who insisted on a vacuum purge (and associated cost) when presented with any completely depressurized bottle. The last time I built a bottle from scratch (medical D plus aviation CGA540 valve), I purged it myself using my vacuum bagging pump, put about 100 PSI of O2 in it from the welding rig, and then took it to the refill place and got it filled, no problem.

--Bob K.

Every welding O2 supply house I have been to exchange the cylinder, not re-fill it. It is just so much faster for a welder that needs to get back on the job. This exchange would be only for standard sizes. This may be fine for your glider but in my particular case (Schleicher) I haven't found a welding supply house yet that has the correct (exchange) size for my sleeve. Most glider operations out west can refill for you. You might try medical supply houses.

On Monday, June 4, 2018 at 5:58:37 AM UTC-7, OHM Ω http://aviation.derosaweb.net wrote:
Every welding O2 supply house I have been to exchange the cylinder, not re-fill it. It is just so much faster for a welder that needs to get back on the job. This exchange would be only for standard sizes. This may be fine for your glider but in my particular case (Schleicher) I haven't found a welding supply house yet that has the correct (exchange) size for my sleeve.. Most glider operations out west can refill for you. You might try medical supply houses.

I was meaning a standard cylinder that you then transfill into the glider cylinder. Yes the OP may not have an easy or safe way to carry the cylinder that, but that's how some folks without other options do this. No I would not carry a cylinder around in a car.

Many gas suppliers will fill your own non-rental cylinders as long as the inspection is current and they are properly labeled. Some will hydrotesr/recertify out of date cylinders and then fill them. Anything labeled medical or aviators breathing oxygen increases chances it won't get filled as regular industrial oxygen.

The discussion above already covered why you don't say the word "medical".

Mountain High has a discussion on their FAQ page regarding different sources/types of Oxygen and confirms that it is all the same.

As others have stated, the best solution is to rent a bottle locally and return it when you leave. May be prudent to call ahead and reserve one. Having two aircraft bottles works well. Swap out full for empty and refill at your leisure.

Also concur that large high pressure oxidizer bottles and transfill systems need to be treated with much respect.

Thanks for the info.