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Learning, Sharing, and Teaching => Do it Yourself Discussion! => Topic started by: onemorebike on December 09, 2018, 05:46:54 AM

Title: Help with soda stream hack (co2 tank)
Post by: onemorebike on December 09, 2018, 05:46:54 AM
I hacked my soda stream to provide more co2 for the buck, connecting a hose instead of the cartridge to a large 20lb tank of co2. The only issue I'm running into is the co2 is intermittent, only ever another pump (or so) does it come out as forcefully as the old tanks that soda stream sells. Sometimes if move the tank or soda stream unit it will return to its normal force but then die back down. I'm wondering if hose length or path should matter or where I should be looking for issues because I'm stumped.

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Title: Re: Help with soda stream hack (co2 tank)
Post by: Case on December 10, 2018, 08:23:25 AM
I hacked my soda stream to provide more co2 for the buck, connecting a hose instead of the cartridge to a large 20lb tank of co2. The only issue I'm running into is the co2 is intermittent, only ever another pump (or so) does it come out as forcefully as the old tanks that soda stream sells. Sometimes if move the tank or soda stream unit it will return to its normal force but then die back down. I'm wondering if hose length or path should matter or where I should be looking for issues because I'm stumped.

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How are you controlling the pressure delivery with your new tank?  A regulator?  What is the volume of your tank?

Here is my understanding of the physical chemistry of this; perhaps a physical chemist or chem E can correct any mistakes I have made, for I am just a lowly synthetic chemist.

The pressure inside the soda stream tank should be determined by the vapor pressure of carbon dioxide at room temperature, looks to be a little over 800 psi.  That's pretty damn high pressure for something a regular consumer would be using, so those tanks that soda stream sells must be pretty thick aluminum.

The volume of the tank (minus the volume of non-gaseous CO2) will determine how much gas you can deliver.  As you deplete the reservoir, the non-gaseous CO2 (I believe it is liquid under pressures/temperatures typically in a sodastream bottle; e.g. room temperature and a few hundred PSI) will begin to re-equilibrate with the system, eventually bringing it back to the original vapor pressure of CO2 at the given temperature.  I think larger excesses of CO2 will allow for faster re-pressurization of the tank.  Eventually you run out of CO2 and the pressure goes down.

Since your tank is running into the slow down stage, I would guess it means you are low on CO2.  This happens towards SodaStream bottles as well, when they run low on CO2.  Therefore, you should refill it.

Please keep in mind that you are working with high pressure gases... would be wise to learn about safety mechanisms, how much pressure the tank can handle, how much pressure is made by the CO2, etc...
Title: Re: Help with soda stream hack (co2 tank)
Post by: HipGnosis on December 12, 2018, 01:02:43 PM
I use 20oz paintball tanks to carbonate water (which I add DIY soda syrup to).
I suspect your big tank is freezing up your soda stream, and that it defrosts while you're moving the machine or the tank.
Do you have a pressure or flow regulator on your tank or hose??
Title: Re: Help with soda stream hack (co2 tank)
Post by: onemorebike on December 12, 2018, 05:35:01 PM
I use 20oz paintball tanks to carbonate water (which I add DIY soda syrup to).
I suspect your big tank is freezing up your soda stream, and that it defrosts while you're moving the machine or the tank.
Do you have a pressure or flow regulator on your tank or hose??
No pressure or flow regulator, just the hose I ordered off of eBay that claims to be a converter. The soda stream has settled into alternating a good strong blast of co2 with a much smaller one but then comes right back on the next pump (and so on). Do you think this would be consist t with freezing?

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Title: Re: Help with soda stream hack (co2 tank)
Post by: HipGnosis on December 12, 2018, 06:50:00 PM
I use 20oz paintball tanks to carbonate water (which I add DIY soda syrup to).
I suspect your big tank is freezing up your soda stream, and that it defrosts while you're moving the machine or the tank.
Do you have a pressure or flow regulator on your tank or hose??
No pressure or flow regulator, just the hose I ordered off of eBay that claims to be a converter. The soda stream has settled into alternating a good strong blast of co2 with a much smaller one but then comes right back on the next pump (and so on). Do you think this would be consist t with freezing?
It could be, but I can't say for sure.
Try closing the valve on the tank and ever-so-gradually open the valve until the soda steam flows co2 when you pump it.
Title: Re: Help with soda stream hack (co2 tank)
Post by: onemorebike on December 12, 2018, 06:51:50 PM
Per the recommendation from the welding shop I bought the tank from, I keep the tank in the closed position unless I'm using the soda stream, then I open it up the whole way. Is that a mistake?

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Title: Re: Help with soda stream hack (co2 tank)
Post by: mrmoolaman on December 12, 2018, 10:21:42 PM
Ya, that might make it freeze up. When compressed fluids expand, they cool and want to absorb energy, so if you're allowing that to happen to quickly then it might freeze up a narrow line.

Like mentioned above, I would open the valve just enough that the soda stream works, then it might not freeze up.