Is it possible to repair a leaking low-pressure CO2 cylinder?
January 4, 2021 2:20 PM   Subscribe

I got a 20 pound CO2 cylinder and retrofitted my SodaStream to use it. It was amazing (lasted 11.5 months! cost <$20 to fill!). I think the valve was damaged on the way to refill it, however, as it has now essentially emptied in a matter of days.

I am a bit of a fool. I put the cylinder in the trunk of the car and it was rolling around on my way to the refill place. It has a simple hard plastic handle, not a full cap to cover the main valve. I think the main valve got damaged when it rolled around. The tank was cold and had condensation on it when they returned it from refill. It stayed cold. These are all indications of a leak (PV=nRT). So, can I repair the main valve (or how would I locate suitable repair facility)? Do I need to replace it?
posted by profanon to Home & Garden (8 answers total) 1 user marked this as a favorite
You do not want to mess around with any compressed gases above bicycle tire pressure. Catastrophic failures are rare but they can happen. Thousands of PSI / hundreds of bar is enough to kill someone if it vented all at once. I would take it to facility that services tanks, such as a scuba center, or your local hydro test facility would almost certainly be able to recommend someone. Valves are cheap, but do you know how to torque it when you install it? I'd gladly pay a few bucks for an expert to take care of it properly.
posted by wnissen at 2:44 PM on January 4, 2021 [6 favorites]

The people who fill the tank should be able to point you in the direction of a local place where you can replace the valve or exchange the tank, if they can't do it themselves.
posted by mskyle at 3:04 PM on January 4, 2021 [4 favorites]

Are you sure the valve was totally closed? If it is the valve, replacement is for a professional, although I would guess you are close to the cost of a new tank
posted by Muted Flugelhorn at 6:34 PM on January 4, 2021

The closest I have ever come to dying was when an unsecured CO2 cylinder fell over in the back of my car as I was making a left turn onto a two lane country highway and the valve was knocked enough to open up. My car immediately filled with CO2 vapor and I couldn’t see a thing. Luckily there were no other cars on the road as I swerved over to the shoulder with one hand while opening the drivers side window with the other. Despite getting out of the car within probably ten seconds of the valve opening I still felt the “kick” of the gas as I opened the door to get out. One more breath in that car and I would have gotten knocked out and asphyxiated. Luckily I’d recently had safety training on CO2 in confined spaces and knew exactly how dangerous it was (but was still foolish enough to not secure that tank). It’s no joke, that stuff will kill you. You really shouldn’t transport cylinders inside of vehicles in the first place, but if you do make sure they are secured!
posted by Jawn at 7:25 PM on January 4, 2021 [4 favorites]

I don't know about repair, but I will say that if you're using/storing CO2 tanks indoors, you should buy a CO2 meter, and ideally one with an alarm loud enough that it will wake you up if you're asleep. The effects of CO2 can be significant and noticeable even at "a bunch of people are in a room with inadequate ventilation" levels, adding a concentrated CO2 source to that can be very bad and potentially fatal, as Jawn mentions.
posted by wesleyac at 9:14 PM on January 4, 2021 [1 favorite]

Look for "industrial gases" supplier near you. They should have staff that can replace the valve for you at a very reasonable cost.

I just typed in "industrial gases near by" and I got 3 entries right away. I'm in San Franciso and my local stop is Prax-air and Airgas. They are often called welding gas supplies. But they'd have CO2 available too. They can test the valve and tank for you, and if need be, sell you another valve or tank, and even sell you refills.

And please strap down the tank on some moving blankets so this doesn't happen again. I'd put it in the backseat with seatbelts on if it fits.
posted by kschang at 12:12 PM on January 5, 2021

The valve and connectorized part of a talk can be removed and replaced. Don't try do it yourself. If you've got a local re-filler that does pressure tests on old tanks, they can probably either tell you where to fix it or give you some trade-in value on a swap for a used but tested good tank. Assuming you don't lie to them, they'll refuse to refill this tank as-is.
posted by eotvos at 12:18 PM on January 5, 2021

Response by poster: Good news, everyone! After a bunch of calling around, it turns out the place where I had it filled, a large industrial gas supplier, will probably fix it for free. Apparently it's relatively common that the aluminum cylinders used for smaller CO2 tanks often loosen relatively easily from the brass valves. Thanks for all the helpful feedback.
posted by profanon at 7:09 PM on January 6, 2021 [1 favorite]

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