Sodastream cylinder for drysuit inflation?

[ChrisMBC]

Due to my partner’s Sodastream habit, I find myself with access to a lot of functionally free, within-hydro Sodastream cylinders. They’re a little longer and thinner than the typical AL6, with a service pressure of 250 bar and an internal volume of 0.6ish litres, giving them ~5 cubic feet of ‘free air’, which should be plenty for a single T1 dive.

The cylinder threads are M18 x 1.5, which seems to be the same as cylinders used for rebreathers in Europe. I can quite easily find valves for M18 -> DIN online.

Before I throw away $45 on a valve, does anyone have any thoughts/experience using these as suit inflation bottles?

 

[Gone for diving]

Always thought they would make great o2 bottles for a rebreather....

I believe aliexpress has those valves as well.

How are they free? Seems they always want a core when you buy a new one.

You really should refill them with co2,
You can very reasonable find welding or fire prevention tanks quite cheap. (And has a ton of refills...)
And plumb directly to the sodastream
Or I refill my own....

 

[ChrisMBC]

How are they free? Seems they always want a core when you buy a new one.

They do, but we’ve acquired a lot of extra cylinders, when someone is selling/giving away a machine/plastic bottles, they often seem to want to give away the cylinders as well. We have something like 8 or 9 spare in a cupboard, I doubt my partner would miss one or two. Cheaper than an AL6 anyway!

 

[davehicks]

I am going to venture that this is a bad idea. Is the valve and tank connection really robust enough for being used in a rough and tumble diving environment? This seems like a bad way to save $50 bucks.

 

[Tracy]

I don't see any reason it wouldn't work. Check out the inside thoroughly, CO2 is a hard life for tanks.

 

[elmo]

Due to my partner’s Sodastream habit, I find myself with access to a lot of functionally free, within-hydro Sodastream cylinders. They’re a little longer and thinner than the typical AL6, with a service pressure of 250 bar and an internal volume of 0.6ish litres, giving them ~5 cubic feet of ‘free air’, which should be plenty for a single T1 dive.

The cylinder threads are M18 x 1.5, which seems to be the same as cylinders used for rebreathers in Europe. I can quite easily find valves for M18 -> DIN online.

Before I throw away $45 on a valve, does anyone have any thoughts/experience using these as suit inflation bottles?

Before doing anything with these cylinders are you sure the 250 bar is the working pressure (eg indicated by PW250BAR) and not the test pressure (PH250BAR). The pressure of CO2 at room temperature only reaches around 60 bar before it turns to a solid. If the test pressure of the cylinder is 250 bar, working pressure is likely to be around 2/3 that (depending on the applicable standard), ie 167 bar.

 

[stiebs]

I've thought of this too, but for the workbench for bubble testing a first stage after service - very convenient to submerge. Alas its the test pressure, not working pressure that is 250bar. And I'm not really that keen on putting my own valve on it an regularly filling myself to 170bar. I'm sure it's all OK. Until it isn't.

 

[rjack321]

Before doing anything with these cylinders are you sure the 250 bar is the working pressure (eg indicated by PW250BAR) and not the test pressure (PH250BAR). The pressure of CO2 at room temperature only reaches around 60 bar before it turns to a solid. If the test pressure of the cylinder is 250 bar, working pressure is likely to be around 2/3 that (depending on the applicable standard), ie 167 bar.

Yeah which makes them 3-3.5cf. In theory just barely enough for a modest square profile T1 dive. Plan on it running out just when you want that tiny bit more loft in your suit at 9m

 

[happy-diver]

I collected a few of the steel bottles from opportunity shops in the 90s and with a dive shop owner
and no real time invested despite having a lathe we could never figure out how we could use them

Twin tanks with a hose into a fishbowl to put on the head of a cat

 

[rob.mwpropane]

Due to my partner’s Sodastream habit, I find myself with access to a lot of functionally free, within-hydro Sodastream cylinders. They’re a little longer and thinner than the typical AL6, with a service pressure of 250 bar and an internal volume of 0.6ish litres, giving them ~5 cubic feet of ‘free air’, which should be plenty for a single T1 dive.

The cylinder threads are M18 x 1.5, which seems to be the same as cylinders used for rebreathers in Europe. I can quite easily find valves for M18 -> DIN online.

Before I throw away $45 on a valve, does anyone have any thoughts/experience using these as suit inflation bottles?

Get a larger 20# tank and run a line from under the sink. They make lines already made on Amazon. I like soda water, and I drink a lot. I can go through 20# in about 6 or 7 months, but it only costs
$35 to exchange it. I don't remember what those 1# cost.. but they were not cheap. Will save you a good bit of money if your partner rolls through them.

I found someone practically giving away a 20# on marketplace. The line from Amazon might have been $25.