Refill sodastream bottles

[peebee]

A new "SodaStream" ("Tr21-4" thread) to UK CO2 cylinder ("W21.8-14" thread) adapter arrived yesterday (I wasn't keen on the "elbow" adapter supplied with the filling attachment, because I know from experience the tiny O-rings in the on-off valve fail easily) so I quickly applied the previous post's thinking and filled it from the upright cylinder:

The straight-through adapter certainly look robust (it is one of these, there's an example of the 'usual' adapter here) but took some time to get the "pin" right (the "pin" depresses the valve on the SodaStream cylinder), eventually screwed the "pin" fully home and put in an extra silicon washer (to total 2) to get the packing right (so the SodaStream can be unscrewed to disengage the "pin" but the washers stay sufficiently seated to stop a release of gas - any residue of gas can then be released with the bleed valve on the filling adapter before completely removing the cylinder). I'm a bit worried how long the seals will last on the filling adapter's on-off valve.

I tared the cylinder so I could see how much liquid gas I'd get in during the next step. Reassembled the cylinders, opened the valves and tipped the assembly carefully over. After a couple of minutes, close valve, turn back upright, remove cylinder, and weigh. 12g increase, well that never worked. Try again … 22g. Seems there might be more to this chilling of cylinder than my simplistic explanation captures? I'll try again but first chilling the cylinder like @LeeH says.

The "filled" cylinder now has a gross weigh of 0.875kg. Stamped on the cylinder is "tare" followed by two weights (0.75kg and 0.453kg), and printed a weight of 425g CO2. Doesn't seem to make sense. 0.453 (tare?) + 0.425 (nominal contents) = 0.878, which is my gross weight, but then how did I fill it with liquid when the donor cylinder was upright? It would have helped if I'd weighed the cylinder when empty of liquid (only about 200psi left).

Okay, so I'm baffled.

 

[LeeH]

Things I found out by playing with these.

• Soda bottle in the freezer
• Doner bottle upside down
• INSURE the pin is OUT when you screw the bottle on, or you will A bend the pin, B knacker the valve
• With your bottle connected, turn on the donor bottle valve and the pressure should open the soda valve a tad and liquid will flow due to the pressure differential.
• VERY gently close the pin until you here a little more flow. A fill should take around 30 secs.
• Close the donor bottle valve, retract the pin, vent and unscrew
• If you have damaged the soda valve get ready for a cold hand as it will just empty very quickly

Been there, done all of the above, it’s advice from experience.

You can get the full 425g of liquid in with no issue. With the bottle upright you’ll just pressureize the soda bottle to 500psi...no liquid unless your tank has a dip tube.

 

[peebee]

ERRATUM: May have made an incorrect statement earlier: You could overfill a cylinder, but you are unlikely to succeed. In a completely full cylinder the liquid is still subject to thermal expansion and would apply a hydraulic pressure on the cylinder which will either expand elastically, expand plastically (deform), or burst (Soda Stream cylinders have a burst disc that would probably go first).

"Full" Soda Stream cylinders are about 2/3 full of liquid (425g in about 0.666 litres). So perhaps weighing the filled cylinder isn't so daft? (To weigh while filling you'd need a flexible hose connection which I've already declared as giving me the willies - but it's what the paintball bunch seem to do, e.g. NOTE: A "syphon CO2 tank" is a cylinder with dip-tube).

Things I found out by playing with these.

• Soda bottle in the freezer
• Doner bottle upside down
• INSURE the pin is OUT when you screw the bottle on, or you will A bend the pin, B knacker the valve
• With your bottle connected, turn on the donor bottle valve and the pressure should open the soda valve a tad and liquid will flow due to the pressure differential.
• VERY gently close the pin until you here a little more flow. A fill should take around 30 secs.
• Close the donor bottle valve, retract the pin, vent and unscrew
• If you have damaged the soda valve get ready for a cold hand as it will just empty very quickly

Been there, done all of the above, it’s advice from experience.

You can get the full 425g of liquid in with no issue. With the bottle upright you’ll just pressureize the soda bottle to 500psi...no liquid unless your tank has a dip tube.

The paintball gang vent Co2 out of the partially filled bottle to cool it. Bit wasteful though.

Because I'm using fixed adapters I can't have the "pin" anything other than "in". But it isn't going to bend! But I now know I can have the pin too far in and this will close the valve again; hence I was having such trouble getting it to adjust right, until I put an extra silicon washer in.


A better (than my earlier) explanation of "why cool the cylinder" is less pressure is needed to keep the CO2 liquid, so the donor cylinder can push more liquid into the cylinder being filled. I'm getting the impression that the gaseous CO2 in the cylinder being filled needs positive encouragement to move out of the cylinder and be replaced by liquid CO2 (it is having to force past some pretty tight constrictions in those valves).

A possible explanation of why two Tare weights: One is for cylinder only (which is precise to the gram), the other is for cylinder plus valve (which is more of an estimate within 10g)? This suggests a gross weight of 750+425=1175g, which is about 100g more than some published figures I see. Anyone else?


(EDIT: I've seen some instructions suggesting gross weights of over 1200g, so 1175g isn't an unreasonable gross weight).

 

[peebee]

Cold (-18C) SodaStream cylinder (and cold filling adapter for good measure) and tried again. Weight of cylinder went from 875g to 1110g. If reading the cylinder markings correctly that's 360g of CO2.

Chilling the cylinder again might make up the extra 65g found in a new full cylinder (425g)? But that would be too much effort for little gain. I'm not worried about "overfilling" it because that would require some gymnastics to upend the remaining gas-space in the receiving cylinder which is hardly recommendable given the heavy combined weight and dangerously vulnerable coupling between cylinders. However, if you were using an upright donor cylinder with dipstick you should rethink that. (Rethink any arrangement that has an upright receiving cylinder).

I'm still not convinced I'm explaining "why cool the cylinder" right, but it's an essential part of getting the cylinder filled. Can anyone convince me why?

 

[xozzx]

What is the concern with overfilling the receiving cylinder? The pressure will remain the same (same as the donor cylinder) as they will have equalised during filling. The only difference I can see is there would be more liquid in the receiving cylinder, which I guess could damage the regulator. In this case you could just reconnect the transferring manifold and purge out a little of the liquid.

Am I wrong? Still waiting for my refill manifold to arrive (and dont have an empty sodastream cylinder yet) so following the comments with interest.

This is the one I bought - https://www.ebay.co.uk/itm/DIN-477-...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

 

[peebee]

What is the concern with overfilling the receiving cylinder? …

Covered in post #23 above ("erratum"). But there isn't much hope of filling completely, you might rig something up with the flexible connector you'll have, but you'll have to go out of your way. And a "full" SodaStream cylinder is actually only 2/3rds full of liquid (425g). If you actually manage to get 650+g of CO2 in these cylinders I think you should be seriously concerned!

I've been glad of this discussion. The process terrified me before! And I had a cylinder to fill, like "now". You do need to be cautious (850PSI is a lot of pressure, and escaping and expanding gas does get very, very, cold), but I think you have to be doing something pretty exotic to have exploding cylinders, adapter projectiles, and like; most errors seem to result in disappointingly (low) filled receiving cylinders.

 

[Andrew Chapman]

Hi all, don't suppose any uses just sodastream bottles and gets them refilled anywhere do they?

 

[xozzx]

Hi all, don't suppose any uses just sodastream bottles and gets them refilled anywhere do they?

Do you mean for Corny kegs?
If so I would imagine this is a way more expensive way of doing it.
Sodastream bottles are 425g CO2 at probably best £10 per fill = ~£20/kg.
I get 6.25Kg bottles from Hobbyweld for £35 = £5.60/kg. A lot of people get big bottles CO2 much cheaper than this.

 

[Andrew Chapman]

Do you mean for Corny kegs?
If so I would imagine this is a way more expensive way of doing it.
Sodastream bottles are 425g CO2 at probably best £10 per fill = ~£20/kg.
I get 6.25Kg bottles from Hobbyweld for £35 = £5.60/kg. A lot of people get big bottles CO2 much cheaper than this.

Wow thats huge price difference (apologies, new to this!) so big bottle, and fill a sodastream for transporting seems the best option.

Any experience with innergy? Local gas supplier

 

[xozzx]

Any experience with innergy? Local gas supplier

Ive never heard of them but their website seems to show they are a hobbyweld supplier, but the link doesnt show anything.

A couple of other points...
Using a bigger bottle you will need to pay a deposit, think hobbyweld is £65. You then pay £35 to swap the empty cylinder for full (ie refill) and if you return the cylinder you get the deposit back.

Some suppliers will charge a monthly rental on the cylinder. Unless you are using a lot of CO2 this tends to be much more expensive so best to avoid ones with rental charges.

A lot of people will use fire extinguishers or welding gas but I prefer to play i safe and only use food grade CO2 (hobbyweld offer foodgrade)

 

[LTgoodevil]

Sorry for resurrecting the thread, but I've just bought SodaStream with intention to keep refilling canisters at home and have few questions.

1. I'm planing on getting either DIN 477/ W21.8 CO2 Fill Station For Filling SodaStream Tank,10" Hose,With Gauge | eBay or DIN477 W21.8 Tank CO2 Refill Adapters Connector Set For Filling SodaStream Tank | eBay I assume both of these will work fine with UK canisters
2. How you guys order canisters? I've contacted jespgases and asked for prices and if they have dipped canisters (so I don't have to turn canister upside down while refilling). They asked for what purpose I need it and I've stated - to refill SodaStream canisters. I've been told they not gonna provide me with canisters for this purpose . Should I not ask about dipped ones and just say I need canister for beer dispenser? If they ask for more questions about these I wouldn't be able to answer obviously.

I highly appreciate your help.
PS. I would be following this guide SodaStream Cylinder Refill Adapter Instructions | CO2 Supermarket which is in line what you guys been discussing

 

[xozzx]

@LTgoodevil I just use a non dip tube cylinder upside down. It is a hassle but I think any CO2 supplier has to ask what purpose you are buying the cylinder for. Im not sure a legitimate home use for food grade CO2 with a dip tube. If you are happy with non food grade (there are plenty of arguments both ways, I wouldnt risk my health for the convenience) you could say it is for welding or you could use a CO2 fire extinguisher.

 

[LTgoodevil]

Thank you very much. I'll go on food grade non dip tube cylinder upside down route. If asked for purpose do you think reply - for carbonating drinks and dispensing beer - be sufficient and not result in any further questions?

 

[xozzx]

I have 2 cylinders and both times I just said it was for homebrew, no more questions asked

 

[xozzx]

I guess most people dont know much about homebrew, you could try requesting one with a diptube and say it is for homebrew... they might not question it

 

[Falco]

I'm also thinking of going down the DIY refilling route so does anyone use this cylinder from Hobbyweld? No mention of it having a diptube or not, not even in the data sheet download.

Would be good to know how others have used this particular cylinder.

Cheers

 

[xozzx]

I'm also thinking of going down the DIY refilling route so does anyone use this cylinder from Hobbyweld? No mention of it having a diptube or not, not even in the data sheet download.

Would be good to know how others have used this particular cylinder.

I use that cylinder and refill sodastream bottles from it. Works fine, just a bit awkward as you need to turn it upside down.

 

[Falco]

I use that cylinder and refill sodastream bottles from it. Works fine, just a bit awkward as you need to turn it upside down.

Thanks for that xozzx

 

[Falco]

Well I’ve purchased this from Amazon CO2 adapter and together with this Hobbyweld CO2 cylinder refilling is not complicated at all. As @xozzx says, you just need to invert the cylinder before refilling. And freeze the Sodastream cylinders for a few hours beforehand. Lots of how-to video’s on YouTube. Thanks for this thread everyone

 

[LTgoodevil]

Thank you guys for all the help! My original cylinder ran out last week so got 6kg food grade CO2 cylinder delivered by http://www.thebeerandgasman.co.uk/gases-home-brewers/ in Coventry today. As I was thirsty and couldn't wait for keeping SodaStream cylinder in a freezer for 2 hours, I refilled it as it was with both cylinders upside going from 750g to 920g. Definitely will freeze it next time