# CO2 connections



## TDI-line (28 Jan 2008)

Does anyone know if the C02 gas bottles we use are the same male iron thread as a paint ball gun, they use 12 and 20 oz. 

I think it may be 5/8 th.

Thanks,

Dan.


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## GreenNeedle (9 Feb 2008)

I think they are different.

Loads of threads on the APC website r.e. paintball and sodastream bottle setups.

From what I remember they are usable with certain adaptors but at the end of the day I think the fire extinguisher route must be cheaper (and most definately easier).

Andy


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## TDI-line (9 Feb 2008)

What i was thinking was hiring a large 35kg co2 bottle, and needing the correct decanting device so i could do refills alot cheaper than our local lfs.   

And would be good if we ever had a meet/event at my place, then i could top up as well.


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## Hoejay (9 Feb 2008)

You might find it difficult to get a supplier  to deliver to  a personal address. You will probably need a business account and a business address. This is certainly true of diving gasses such as oxygen & helium from suppliers auch as BOC and Lindegas,. 

Also the rental cost of the cylinders is fairly high, so you need to turn the cylinder round fast to cover this cost. Depends on how many cylinders you need to fill. 

I assume you will be decanting into your smaller cylinder(s) and do not have a pump to pump the gas out. This will also mean that you will reach a point where both cylinders ( supply and destination) have the same presure. i.e 50 bar in each cylinder . Unless you have a few spares or are filling cylinders for others, the remaining gas (50 bar) goes to back the supplier when you exchange your supply cylinder. 

You coul d keep on partially filling sucessive fills but each time the gas equals out the gas won't flow any more. The gas in your small cylinder will need to be  refilled at shorter and shorter intervals and the fill pressure becomes less and less. 

Depends on the ratio of  the volume  of supply to destination cylinder how much gas you finally waste. This may be a lot of gas in a large supply cylinder. It could be equal to severall small cylinder fills, but you cant get it out because there is too small a gas pressure. 

It may be a better option to use the larger cylinder to feed the supplies to several tanks via a manifold. I think this is what Tom bar does.

Either way ther will be a final pressure at which the regulator will not work. The larger the cylinder the larger the volume of gas in that cylinder you have to waste.

Try a search on partial pressure filling of gasses and or casscade and decanting methods for gas filling

Hope this makes sense.

Neil


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## ceg4048 (9 Feb 2008)

TDI-line said:
			
		

> What i was thinking was hiring a large 35kg co2 bottle, and needing the correct decanting device so i could do refills alot cheaper than our local lfs.
> 
> And would be good if we ever had a meet/event at my place, then i could top up as well.



Dan, I'm pretty sure that the high weight bottles are filled with liquid that vaporizes before entering the regulator from the decanting device mounted inside the bottle. 

As a result, as Neil alluded to, the _mass_ of gas you would get from your proposed decanting procedure would be minuscule due to pressure equalization. A more dependable source of CO2 would be the fire extinguisher route or to rent larger mass bottles from BOC. You would pay the monthly rental but the bottle would last the whole year.

Cheers,


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## JamesC (9 Feb 2008)

You can do and it does work fairly well. The thing you have to remember doing is that if the donor cylider doesn't have a dip tube inside then you will need to turn the cylinder upside down so that liquid CO2 comes out. Used to be fairly common with paint ballers as they could go to a meet and just keep refilling their small cylinders up.

Team onslaught website with lots of CO2 info - http://www.teamonslaught.fsnet.co.uk/co2_info.htm

If it's worth the hassle though is up to you.

James


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