Revisiting an old topic: Welding O2?

[Thalassamania]

You guys are nuts using industrial/welders O2 or balloon grade HE. Work a few hours longer to afford the proper grade and live a full life...

While it's not the case for He, all O2 grades come off the same cooling tower. It's only a question of how the flask that you bring in for filling is handled.

 

[Scott L]

While it's not the case for He, all O2 grades come off the same cooling tower. It's only a question of how the flask that you bring in for filling is handled.

My tech instructor scared the bejeebers out of me telling me otherwise. but I will defer to your knowledge as you have not steered me wrong yet...

 

[Thalassamania]

Things could be different in different times and places. Ask your supplier. I think that what you'll find is that the only difference is pulling a vacuum on the flask before filling. Let me know if they tell you different, please.

 

[oxyhacker]

If you have some secret info we don't have concerning fatalities caused by the use of welding O2, by all means let us know. But if you look at the specs welding O2 is actually purer and cleaner than med, the only difference if any being in vacuuming the tanks, and that varies with the supplier, hence the recommendation to call the plant or lab.

Since helium is used mostly for precision welding and analytical work, all the grades are pretty clean, but if you want to be extra safe, just buy one of the better ones.

Balloon grade? It's not really, technically speaking, a grade, but rather an ungraded or sub-grade, and can indeed conceal all sorts of vices. But you got to be pretty clueless to use it diving. USP medical helium, for that matter, is only two nines (99.0%) according to the specs, while the cheapest welding/industrial grade you'll usually run across is 99.5% to 99.95%.

You guys are nuts using industrial/welders O2 or balloon grade HE. Work a few hours longer to afford the proper grade and live a full life...

 

[Cave Bum]

But if you look at the specs welding O2 is actually purer and cleaner than med, the only difference if any being in vacuuming the tanks, and that varies with the supplier, hence the recommendation to call the plant or lab.

One of the things I like to point out to folks is that most of the oxygen we buy is generated from cryogenic liquid oxygen. No matter the grade, it all comes out of the same cryogenic tank and through the same lines. This means it’s being generated from liquid at a temperature of -297.3°F (-183.0°C). Since water freezes at 32°F (0°C) the only H2O contamination we can get in generated O2 has to be added after the generation process. This also applies to just about all other types of contamination as well. The ‘grade’ specs deal more with how clean the containers you are filling are kept then with the purity of the gas that's being put into them.

 

[WD8CDH]

No, what I'm asking is if you're adv nitrox trained, or have DAN O2 certification, dive shops will fill oxygen tanks for you. Then if you have an HP tank (~3500 psi), and if they aren't scared and have a booster, will they fill it to the rated pressure? DAN O2 cert would be the cheap way to go if you just need the cert to obtain O2.

If you have access to a booster that is O2 cleaned, that would be another option.

Like I said, I have no problem filling at home. I can fill to 3500 easily there. The problem has getting small cylinders filled in the field.

No, I don't have a DAN O2 cert. I was trained and had 10 years and over 1000 hours of rebreather, heliox, and tri-mix experience before DAN even existed. I did get recreational OW and AOW back in the early '70s (by assisting instructors so it was free ). The DAN O2 cert sounds like a good affordable solution, I hadn't thought of that. I really don't want to sit thru NITROX and Advanced NITROX just to do what I have been doing for almost 40 years.

 

[WD8CDH]

Well, I think I found the solution to getting small individual RB bottles filled at an unknown welding gas supplier. I machined a CGA540 nipple(chrome, hand-tight, of course) to fit my Poseidon O2 regulator inlet. I then put a compact Sherwood chrome CGA540 valve on a D size med oxygen bottle. I then took it to a welding shop that didn't know me and told them it was for a portable welder for my 4x4. After they filled it, they reminded me keep grease from the truck off of the valve and gave me a valve protector with their name and phone number on it.

Other than needing an adapter to fill the O2 bottle at a diveshop, I don't see any downside to using the CGA540 fitting on the RB.

 

[Thalassamania]

Sweet.

 

[WD8CDH]

Just an update. I have been to 4 different welding gas suppliers with my "portable welder O2 tank" and had no problems getting it filled at any of them. Two required leaving it overnight because they only fill twenty O2 bottles at a time. They usually charge me the same as a 20CF tank even though it only holds 15CF. I know at least one of the shops filled it with the medical tank batch. Several of the counter men drove 4x4s and said they wanted to make up a tank like it for their trucks.

 

[Tigerman]

"make up" being pretty accurate in your case?