anyway to identify which gas is in this cylinder?

BlueKnife · Mar 5, 2025

Bring it to a welding gas supply place and ask them. It's not a rental tank, so you're good there. It's got relatively new-ish looking barcode stickers on it, so it's not way out of date. If I had to guess just based on the pics, I'd say Mig gas of some sort.

disney · Mar 6, 2025

thank you for all your replies, it will be some time before I am able to check it. I will update once I know more. thanks again.

MoArk Willy · May 20, 2025

You only have a couple of choices.
You can take it to a gas supplier and see what they say. If it can be re-certified they may help you with it.
Without the tag and with the amount of rust on the neck ring they may not want to touch it.
It's worth exactly what you paid for it.
Whatever you do....don't light it....that's a reckless move.

yomax4 · May 21, 2025

Tank has a 580 CGA valve. I'd bet it's Helium, Nitrogen, Argon or Argon CO2 Mix. The Distributor won't be able to tell you what it is and they will suggest that you blow it down, purge and refill. As would I.

disney · Sunday at 9:51 AM

ok. so I filled a balloon to the size of a tennis ball, and then with a long aim 'n' flame lighter, tried to light it, and as soon as the balloon melted, it flew away (5ft). but clearly not flammable. I then verified with golf ball sized filled balloon that it puts out a flame. so that should narrow it down to Nitrogen, Argon or Argon CO2 (as Helium would have made the balloon float.) is there any way to see if I connect it to my welding regulator (the type with the ball) and see if the ball floats higher or lower than with a known gas?

WranglerX · Sunday at 1:15 PM

disney said:
ok. so I filled a balloon to the size of a tennis ball, and then with a long aim 'n' flame lighter, tried to light it, and as soon as the balloon melted, it flew away (5ft). but clearly not flammable. I then verified with golf ball sized filled balloon that it puts out a flame. so that should narrow it down to Nitrogen, Argon or Argon CO2 (as Helium would have made the balloon float.) is there any way to see if I connect it to my welding regulator (the type with the ball) and see if the ball floats higher or lower than with a known gas?

Ball type regulator move ball up on volume/flow (CFM or CFH) not of whether gas is heavier/lighter than air (gas type) ....

ultrarunner · Sunday at 1:35 PM

I had a good side business in school picking up cylinders and taking them to the gas plant Cylinder Clinic.

For a fee they would hydro, replace the valve, paint and fill.

Only CO2 could not be converted to other gases because CO2 leaves a residue.

I would then advertise in the penny mart with the new documentation.

Hydro, Paint and New Valve was $35 when I stopped.

Going to a jobber would have doubled my cost so having a full scale plant nearby made it work.

Age of the cylinder was never a issue and on occasion I’m seeing nearly 100 year old cylinders in medical oxygen rotation.

5030 · Sunday at 1:41 PM

Considering how crusty the bottle is as well as the threaded bung, I'd never put any of my regulators on it, sure way to screw up a good regulator. I'd blow it down (outside) and repurpose it into something else. Maybe a 'bowling ball cannon'...lol

I own all the bottles that are used in the shop I own and I get them all refilled as well and never exchange. Kind of **** about nice, clean and unscratched bottles.