Refill sodastream bottles

[xozzx]

Does anyone refill sodastream bottles from their CO2 cylinder. I see a lot of adapters on ebay etc but wondering how safe it is. Are the sodastream bottles rated to the same pressure as the cylinder pressure?

I would need to fill with the cylinder upside down to get the liquid CO2 into the sodastream bottles.

 

[LeeH]

Yes I do, the doner cylinder has to be upside down unless it has a dip tube. The soda stream bottle has to be put in the freezer for an hour before hand.

I bought the expensive co2 supermarket adapter but it broke quite quickly so don’t bother with that.

I use the one in the link, and use it a lot as I refill 2 other people that I brew for.

Easy? Yes, just connect and turn on the flow until you hear it start to fill, then leave it.

Safe? The pressure are the same but are high. With some basic precautions and common sense I guess so.

If you are not a practical person I would say leave well alone.

£1/refill vs £10.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/163681241630

 

[xozzx]

Thanks LeeH. That adapter is one of the ones I was looking at, think Ill order now.

 

[peebee]

Humm? British ( Europe) CO2 cylinder threads are W21.8, a weird combination of imperial Whitworth and metric millimetres. It is very close to G5/8 (BSPP) used by the linked adapter, but it isn't G5/8. I use G5/8 with cylinder threads but the cylinders are old out-of-service cylinders and I use a good bit of PTFE tape (thicker gas stuff) to seal the threads and only pressurise to 60PSI, not 60BAR!

Go carefully (using the correct thread terrifies me; using the incorrect thread … now that is something to get terrified about).

 

[LeeH]

Worth checking the details, the one I bought fits perfectly.

 

[Honk]

Is it absolutely necessary to turn the donor cylinder up side down? I just want the co2 in the soda stream cylinder to dispense from a 5 litre minikeg so thinking 60 psi should be more than enough.
Only recently got the soda stream cylinder but hoping to refill it myself one empty

 

[Honk]

Actually, I'm wondering if I even need an adapter for my purposes, I have a regulater that fits each cylinder so just connect the two using gas line.
Any reason this won't work at lower pressures?

 

[peebee]

Worth checking the details, the one I bought fits perfectly.

It fits okay, it doesn't fit perfectly! Unless of course the Chinese manufacturer are taking shortcuts ("boss, we've only got W21.8 taps and dies not G5/8 … [BOSS] close enough, get it done!"), that wouldn't be out the ordinary for China!

The best document I ever found on the subject was https://www.ftipv.com/bs341-british-standard-cylinder-valve-outlets-connectors/. WARNING: This document needs some careful interpretation, it's not for the bodger. G5/8 is No.6 in BS341, W21.8 is No.8. BS341 is interesting also because it's the only description of the dreaded "POL" thread I've come across (No.4, but it doesn't mention "POL", it is G5/8, but left-hand).

You can even get W21.8 to G5/8 adapters (from China!): https://www.ebay.co.uk/itm/Stainles...hash=item4661bb43a6:m:mw5h3W6MAcn_S3_QyPFDUVA.

NOTE: Both W21.8 and G5/8 (BSP) are Whitworth thread forms, which helps when mashing them together.

 

[peebee]

Is it absolutely necessary to turn the donor cylinder up side down? I just want the co2 in the soda stream cylinder to dispense from a 5 litre minikeg so thinking 60 psi should be more than enough.
Only recently got the soda stream cylinder but hoping to refill it myself one empty

Yes! Unless the door cylinder has a "dip-tube" (e.g. fire extinguisher). Because you want to fill with liquid CO2 not gas.

However, at 60psi (EDIT: up to about 850psi) you are only talking gas, so you don't need the cylinder upside down (upside down is potentially flippin' dangerous, so avoid it if you can).

 

[LeeH]

It fits okay, it doesn't fit perfectly! Unless of course the Chinese manufacturer are taking shortcuts ("boss, we've only got W21.8 taps and dies not G5/8 … [BOSS] close enough, get it done!"), that wouldn't be out the ordinary for China!

The best document I ever found on the subject was https://www.ftipv.com/bs341-british-standard-cylinder-valve-outlets-connectors/. WARNING: This document needs some careful interpretation, it's not for the bodger. G5/8 is No.6 in BS341, W21.8 is No.8. BS341 is interesting also because it's the only description of the dreaded "POL" thread I've come across (No.4, but it doesn't mention "POL", it is G5/8, but left-hand).

You can even get W21.8 to G5/8 adapters (from China!): https://www.ebay.co.uk/itm/Stainles...hash=item4661bb43a6:m:mw5h3W6MAcn_S3_QyPFDUVA.

NOTE: Both W21.8 and G5/8 (BSP) are Whitworth thread forms, which helps when mashing them together.

It was directed at the OP regarding checking the details of the threads for his bottle and the adapter he is going to purchase.

Either way, there is zero chance the one I have is coming off the bottle.

 

[LeeH]

Is it absolutely necessary to turn the donor cylinder up side down? I just want the co2 in the soda stream cylinder to dispense from a 5 litre minikeg so thinking 60 psi should be more than enough.
Only recently got the soda stream cylinder but hoping to refill it myself one empty

Why would you not want to? You cannot fill the bottle if you don’t, all you will do is pressurise it.

 

[LeeH]

Actually, I'm wondering if I even need an adapter for my purposes, I have a regulater that fits each cylinder so just connect the two using gas line.
Any reason this won't work at lower pressures?

I’m confused, you want to apply pressure to the output of a regulator that’s on your soda bottle?

Maybe just buy a refill from the shop.

 

[xozzx]

Thanks peebee. I was searching for the thread type for my CO2 cylinder before buying so havent ordered anything yet.

I found this one https://www.ebay.co.uk/itm/Soda-Str...hash=item54747c5e49:m:mVDh3mb9-WCNnNOmR47uyQQ which has W21.8-14 thread.
Do you know what the 14 at the end is? Will this one fit?

Thanks

 

[peebee]

… Do you know what the 14 at the end is? Will this one fit?

Oh yes. You are going to love this!

A fuller designation for a CO2 cylinder thread is "DIN477 / JIS m22-14 / BS 341 No. 8 / W21.8-14 / .860" x 1/14" which is basically a list of compatible threads. Take "JIS m22-14". Ignore the "JIS" bit (Japanese Industry Standard), we've got M22 which is metric 22mm, and "14" appears again as 14 threads per inch!

Insanity or what?

Actually, I'm wondering if I even need an adapter for my purposes, I have a regulater that fits each cylinder so just connect the two using gas line.
Any reason this won't work at lower pressures?

Regulators are one-way. They may even just vent the (what it sees as excess) pressure on the output side to the atmosphere (you might find my posts on using regulators as "spunding" valves). With no back pressure from the bottle you are filling, its regulator will probably vent all CO2 appearing on its low pressure side to the atmosphere.

It was directed at the OP regarding checking the details of the threads for his bottle and the adapter he is going to purchase.

'Twasn't obvious, but it was a good excuse to air all this thread info again that I've gleaned over time.

Having said I'd prefer to be using the exact thread, the UK cylinder thread details for CO2 mentions m22 and w21.8 in the same designation, but metric (m22) thread form is 60 degrees and Whitworth (w21.8) is 58 degrees. But there's probably some screwy non-sensical reason for that?

 

[xozzx]

DIN477 / JIS m22-14 / BS 341 No. 8 / W21.8-14 / .860" x 1/14

Exactly what I thought, just checking!!

 

[peebee]

Exactly what I thought, just checking!!

Don't say that! If all this mixing up of metric and imperial measurements was "exactly what you thought" then you'd be admitting to have a head as screwed up as mine. And believe me, my head is pretty screwed up! I even carry an ID card to prove it.

But yes, that cylinder refilling station you linked with "W21.8-14" option looks ideal. My slight worry (anxiety comes with the screwed up head) is that hose can handle the 850PSI safely. But you can use "empirical" evidence to consider that's okay; @LeeH is still here after using one!

 

[Honk]

Why would you not want to? You cannot fill the bottle if you don’t, all you will do is pressurise it.

That's all I need to do, pressurise it with enough Co2 to dispense a 5 litre minikeg. Doesnt need to be full, when it runs out I can recharge from main c02 cylinder out in the garage.

 

[Honk]

Regulators are one-way. They may even just vent the (what it sees as excess) pressure on the output side to the atmosphere (you might find my posts on using regulators as "spunding" valves). With no back pressure from the bottle you are filling, its regulator will probably vent all CO2 appearing on its low pressure side to the atmosphere.

I don't believe my smaller regulater is one way, it's a mini one that can be used for 8g ? Cylinders, soda stream or full size bottle depending what adapters you use it with (maltmiller) certainly I've noticed than when changing the mini cylinders the c02 from the keg will vent out through the regulator if I don't disconnect it first.

 

[Honk]

I’m confused, you want to apply pressure to the output of a regulator that’s on your soda bottle?

Maybe just buy a refill from the shop.

It's because I'm not made of money.
Having looked at the adapters I already have I recon I can skip the regulator at the soda stream end altogether, won't know for sure until it's empty.

 

[peebee]

… The soda stream bottle has to be put in the freezer for an hour before hand. …

I've been thinking about this instruction (which isn't an uncommon recommendation): Why? Because a freezer doesn't get where near the temperature to liquify CO2 …

The conclusion I came to (and I'm asking to be corrected if wrong) is, ironically, to try to prevent ice forming and blocking the flow of liquid CO2 'tween cylinders (resulting in underfilled cylinders). Ice (very transient CO2, or "dry", ice) can form as gaseous CO2 expands into the cylinder being filled causing a big drop in temperature, so chilling the cylinder limits the drop in temperature and reduces the risk of ice. I think? I'll change that to "I know" if nobody can come up with a plausible alternative reason.

To take this idea further, and @Honk might like this, filling the bottle slowly from an upright donor cylinder will fill it with gas at about 850 psi reducing the further risk of ice to near zero (zero or negligible further expansion of CO2 in the cylinder to be filled). The cylinder, after a short break to stabilise temperature, can then be filled from the upside-down donor cylinder. NOTE: 850 psi is a lot of pressure; go carefully!

You also see instructions not to "overfill" the cylinder, giving the impression of impending doom if ignored. Such advice isn't repeated in this thread thank goodness. You are filling with a liquid, so it is impossible to "overfill"! For their next trick they probably tell you how to put a quart (of beer presumably) into a pint pot. However I suppose if there isn't a bit of space above the liquid in the cylinder, liquid CO2 could be forced into the regulator? Doesn't seem to bother those who ignore advice and have a cylinder on its side. But rather than trying to fill the cylinder to the nett contents of a purchased cylinder, I suppose you can bleed off (carefully!) any excess in a filled cylinder.