Refillable CO2 cartridges


For those who use these little cartridges, you know how quickly the price can add up.  [steve] takes us through the process of adding a valve to a spent cartridge so it can be refilled. Over all, it doesn’t seem too difficult, and [steve] offers lots of tips to increase longevity and reliability. It isn’t very often that we show a hack here that doesn’t involve some kind of electronics, so take a break from the resistors and microprocessors for a moment and enjoy.

[thanks Wolf]


  1. Davandron says:

    Interesting hack; hope they still work in devices (the neck looks long).

    Reminds me of the post last year(?) about a guy adapting a 20lb bottle so he didn’t have to use those 16 gram cartridges.

  2. kyle007 says:

    seems like alot of work, none the less this makes me want to go out and buy some tools.

  3. mike says:

    That is cool, I can see how schools and stuff could use that in their co2 race car challenges in wood shop class. But it is a little unfeasible, example: My first paintball gun years and years ago was a talon and it used the little co2’s, these wouldn’t work in there at all with the valve because of the extra length (they wouldn’t fit in the grip of the gun where the cartridges go)

  4. Pouncer says:

    very nice…just wish I had a use for it.

  5. jonored says:

    It seems worth note that those little canisters are certainly not designed for repeated filling, which eventually will fatigue the metal and could make the pressure chamber explode. There’s a reason big tanks have a scheduled lifetime and you don’t refill them more than that; they can crack and the results aren’t pretty. Looks like these are more likely to fail in other modes before that, but it’s worth remembering.

    Just wanted to note, as I found no mention of that risk in the howto.

  6. jason says:

    I am confused why do you guys think the canisters are longer than stock don’t the last few steps show the complete canister it looks stock length to me
    am I missing something ?
    I would love to see some details of the refuelling rig for these.

  7. Ryan says:

    IMO Sounds very dangerous. Compressed gasses aren’t something to be toyed with. A tank failing is an incredibly scary thing and even if these are small I would not want to be near.

  8. jason says:

    basic info on his charging systems are here

    I agree that high pressure co2 is dangerous but after reading through his pages I think he knows what he is doing.
    He also says “As for safety, in over seven years of experimenting with these cartridges I have not had any accidents or near misses”

  9. charlie says:

    not something i plan on doing anytime soon. but cool. i do go through a lot of these little cartridges, and it seems there should be something cool to do with the empties. anybody seen any creative ways of recycling them?

  10. @ jonored

    I’ve have steel compressed gas tanks that were pretty old pass the hydro testing fine. In fact, I’ve never seen a steel tank fail short of letting it rust.

    Steel tanks can last nearly forever.

    If you want a cheap tank for welding or something, scrounge around at flea markets for old co2 fire extinguishers. It’s a standard gas tank with a special valve to dispense liquid. Assuming you don’t want to dispense liquid (like for paintball), get yourself a standard valve after it passes hydro-testing.

    you can check welding supply places, total beverage suppliers, and fire extinguisher repair service places for a refill.

  11. Oh, and to no one in particular, the easiest way to center something in a four jaw chuck is to use two allen wrenches at the same time.

  12. Xone God says:

    Excellent hack, (HACKADAY should cover more of these) There are endless uses for these canisters, once a valve is installed. He makes it look easy… then again he has a spiffy lathe. LOL. There was a guy who used to sell the canisters with this mod on Ebay… but I have not seen him post any in at least 2 years… (I wonder if its the same guy.)

    @ charlie, Yes, there are several things you can do with empty Co2 canisters. From the dangerously illegal high power homemade fireworks to a micro-gas-cutting rig. If you need a small amount of compressed gas(es) to operate, actuate, or saturate anything, than this things are the solution. Your imagination is the limit.

    @ jonored You should also note that the smaller the canister the longer it can go with out a hydrostatic test. Not to mention that steel canisters can go for far longer than aluminum canisters as they are less prone to metal fatigue. (12grm canisters are steel.) The danger is minimal as long as you dont over overload them… meaning you DO need a scale with the TARE function to load the 12grams they are rated to hold. If you where to put say 30 grams, and left them exposed to the sun, the valve could give out, leaking the contents of propelling the canister causing damage or in the most unlikeliest of scenarios, the canister could explode. But again, very very unlikely considering all the materials involved.


  13. hangsta says:

    clearly the primary purpose of this is to make whipped cream… right?

  14. i been wrong all these years

  15. “…primary purpose of this is to make whipped cream…”

    No, this is CO2 not NO2.

    Quit huffing the tail-end of the whipped cream.

  16. i have always liked these canisters. Makes me remember back to when i was young and dumb [although i still am both]. Thank god i still have all 10 fingers attached – We used to take those little rocket engines pull the black powder and fill these empty co2 canisters to make mini grenades. Thinking back on how stupid this was i should have been smacked.

  17. DEames says:

    co2 will eat through rubber. If you replace the rubber seal with plastic, your valves will last alot longer.

  18. EdZ says:

    That looks pretty involved. Pity I don’t have a lathe handy: refilling one of these with N2O would be ideal for small hybrid rockets. Though it might just be easier to buy existing 8g cartridges (

  19. Lee says:

    Refilling these disposables is illegal. They are made with a thin wall under an exemption in the CFR49 (rulebook on gas cylinders)There is not enough meat in the wall to properly hold a valve. When filled with CO2, the inside pressure at 70F is 850 psi and at 120F can easily get to 3,000psi. All that is assuming it was filled exactly to the right amount. It is called filling ratio, the weight of the gas charge vs. the inside water capacity. You should never attempt to modify a disposable, instead, buy a small refillable. Safe and cheap. keep your fingers and eyes.

  20. Jdog says:

    I want to aquire higher powered CO2 cartridges. The highest powered CO2 cartridges I found for purchase were 12 grams. Are there higher powered CO2 cartidges out there? Can they be bought or made? Or would that max the cartidges tolerance and explode…? So, does anyone make HIGH POWERED CO2 cartridges and where do I get them?

  21. smartin807 says:

    Looks like the “adding a valve to a spent cartridge” link is dead. It just takes me to a “can’t find the server” message.

  22. rob says:

    i have about 150 lbs of n20 cartridges can you recycle these for money ?

  23. David says:

    12 gram and 16 gram are common for air guns.
    16 gram and 20 or 24 gram are common for paintball guns.
    2 1/2 – 20 lb are common for carbonating drinks. All of them are 850 psi due to the nature of co2. bigger tanks give longer service per charge, but there is no “high powered” co2 cartridges

    and they sell threaded 12 and 16 gram ‘cartridges’ for use in one shot bicycle tire refill gadgets- $3 for the cartridge and $12+ for the tire filler gadget. Buy the threaded ones… their threads are obviously engineered for holding a valve (that’s what they use them for) and get a valve. The hack I would like to see is an adapter to allow refilling the threaded bottles (with the tire valve on) from a 20 lb tank.

  24. Curt says:

    Made several of these. Pretty easy, really, though I prefer to braze the valves in, so I take no meat from the cartridges. Exactly the same length as stock store bought. Working great with LOW pressure air, 250 PSI.
    Now need details on the filling station. It appears the links have been dead for some time.

  25. t-bone says:
  26. Ed says:

    THe link does not seem to be working. I am looking for a way to fill 8 oz co2 cartridges and am wondering if it is worth it to do so or better to just keep buying the 8 oz ones for around 0.33-35 per container.

  27. Ed says:

    THe link seems to be working now, sorry, must have had a computer glitch. Am still wondering if it is worth it refilling 8 oz ones or not though and if it can be done.

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