Soda Stream to Gas MK4 Regulator connector

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melhaer

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I'm fairly sure the W21.8 male would connect to the regulator so am assuming the 5/8" female would go on to the soda stream but please wait for some one to confirm as i'm not sure at all and it dangerous working with high pressures.
 
I got an answer from a seller:

The correct one is:
W21.8 Female to BSP 5/8" Male

You'll need the female thread to take the soda stream bottle and the 5/8 male thread to attach to the regulator.
 
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I got an answer from a seller:

The correct one is:
W21.8 Female to BSP 5/8" Male

You'll need the female thread to take the soda stream bottle and the 5/8 male thread to attach to the regulator.
That does not sound right to me @peebee please can you tell us.
 
Well I purchased some from aliexpress and will see if they will fit once arrived:)
 
That does not sound right to me @peebee please can you tell us.
I've been summoned!



Okay, this is all confusing! We are looking for an adapter which will connect one thread to another, but are talking about 3 threads! Well for a start forget about the 5/8 BSP as that size doesn't relate to anything being talked about here. Male "W21.8" will screw into female 5/8 BSP but fairly loosely so I wouldn't trust it much, especially as we are talking CO2 cylinders holding something like 860PSI (depends on temperature). The regulator will have a female nut with W21.8-14 thread (the most common designation used to describe that thread) which is intended to screw onto the W21.8-14 male thread of a UK/European CO2 cylinder. "14" is the threads per inch (yeah, I know, "21.8" is a size in millimetres; well I had nothing to do with that!).

A Sodastream cylinder has a kooky trapezoid male thread (designated "Tr21-4"), which also needs a pin to depress a valve and allow gas out of the cylinder.

So I think you are looking for one of these: https://www.ebay.co.uk/itm/T21-4-to...098543?hash=item3d920975af:g:PP0AAOSwPuhdY58b (example, other sellers may have them to). They are awkward b...things, because you must screw the pin in "just right" and have suitable seal thickness (I use two seal rings together) or they leak profusely, or no gas comes out at all. Screw the pin in too far an it will force the valve shut again.

Australian/NZ Sodastream cylinders still use 1/2"BSP threads.

I'm slightly worried about putting that enormous regulator on a pokey Sodastream cylinder. Make sure the cylinder is upright (the CO2 is liquid) and make sure it can't fall over! Remember, the pressure in those pokey cylinders is exactly the same as in a damn great big one.
 
Thanks for your detailed explanations!

I will try to fix the Sodastream in order not to fall over, but I am also considering to buy a small regulator to use it with the smallest gas cylinders if I need to use it on a picnic or to bring at friends apartment.

I am brand new to kegging and may be there will be some mistakes...but I am sure that the big regulator will do the job for a bigger cylinder I am considering to buy later and to fill the small Sodastreams from it.
 
I'm double checking this becuase I've seen some things saying Tr21*4 are the old style Sodastream bottles and some where it's the new. Urghh. The 21*4 looks right for the modern ones with the chunker of a thread.
 
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I think Tr21-4 are the old style Sodastream bottles, the 250g ones, not the newer 425g ones. I'll double check and get back.
They did 250g ones? Na, T21-4 is a recent thing designed to make old school nut and bolt engineers look clever in a world dominated by computer geekiness.

Now 1/2" BSP, there's something suitably old!

20190115_200855_WEB.jpg

Here's a new-style Sodastream cylinder with the "alternative" (90degree) style adapter and diminutive "aquarium" regulator (you can't get them regs any longer, but can get very similar). The regulator fitted to the Corny keg is a secondary regulator.
 
They did 250g ones?
Yeah, I've got two of them that I got from charity stall and they said I could just take them. Then I got an adapter you put on to squirt gas into an S30. It's pretty useless now so I was thinking of a way to try rigging it up to barb or John Guest fitting so I could use it with a pub gas bottle. And I've got no actual use for it so I'd give it to my mate because I don't need it. And he'd say thanks and put it in a drawer. And then it would niggle at me because he wasn't actually using it. I'm annoyed with him already.

It's the wording in the listings like this that made me think it was for older bottles. From other listings you can see they mean 10 years old or newer.
 
I've two "midget widget" bottles, they stopped filling them. They've also got 1/2" BSP(P) threads like the old Sodastream bottles. If I knew what I know now I could have refilled them myself. But they are now "repurposed" as 60psi reservoirs on my CO2 lines to keep things topped up when the Pub bottle is closed for the night.
 
Guys, I bought a lot of stuff, I am waiting and I will see if everything fits:) I bought to sodastream adaprots from ALiExpress with controlling valves, but I also bought a mini regulator with a soda stream adaptor:) Will let you know once everything is here and will post close pictures to the adaptors etc.
 
I can confirm that T21-4 to W21.8-14 - is the correct standard for EU/UK bottles. This picture bellow is my case.

But do you know if CGA320 - is the same as T21-4

s-l1600.jpg
 
Thanks, because I am trying to find a connector with a stopping valve, but it is not that important:)
 
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