# CO2 Refill Weight?



## Nick72 (1 Jun 2020)

What should I expect in terms of weight of CO2 when the LFS refills my CO2 Cylinders?

Here are my thoughts.

Example - I have a 3 Liter CO2 cylinder with an empty weight of 2.3kg.

3 Liters of CO2 should weigh 3.042 KG according to this chart: http://www.airproducts.com/Products...ht-and-volume-equivalents/carbon-dioxide.aspx

Let's call it 3Kg.

The safety limit on a CO2 cylinder is 68%.

Therefore my fully refilled cylinder should weight 2.3Kg (empty weight) + ((3Kg x 0.68) = 2.048Kg), so total full weight =  empty weight 2.3Kg + CO2 weight 2Kg =4.3Kg

I ask this because the last 3 times I came home with a refill of this 3 liter cylinder it weighed 4.240kg, 4.120kg and 3.870kg.


Is there anything I'm missing around specific weight or density / temperature or pressure?

(correction my cylinder weighs 2.3Kg empty - updated above)


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## jaypeecee (1 Jun 2020)

Hi @Nick72 

In the UK, the 'norm' seems to be to stick with weights only, not volumes. So, it couldn't be simpler. If I buy a 500g 'cylinder', I am buying 500g of liquified CO2. Volume never enters into it. I haven't needed to buy CO2 for many months but that's what I remember and I can't see why anything should have changed.

JPC


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## Nick72 (1 Jun 2020)

jaypeecee said:


> Hi @Nick72
> 
> In the UK, the 'norm' seems to be to stick with weights only, not volumes. So, it couldn't be simpler. If I buy a 500g 'cylinder', I am buying 500g of liquified CO2. Volume never enters into it. I haven't needed to buy CO2 for many months but that's what I remember and I can't see why anything should have changed.
> 
> JPC



Hi JPC,

Do you refill your 500g cylinders?

Is 500g the cylinder volume or the amount the cylinder can hold after 68% safety factor?

Have you ever weighed your cylinder both empty then full?


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## jaypeecee (1 Jun 2020)

Nick72 said:


> Hi JPC,
> 
> Do you refill your 500g cylinders?
> 
> ...



Hi @Nick72 

Yes, my 500g cylinder is refillable.

I have never needed to consider 'safety factor' - that's probably relevant to whoever refills my cylinders. I'd provide a link to the JBL web site showing my cylinder but it would only confuse as it shows a collection of cylinders!

Yes, I always weighed my cylinder - both empty and full. I don't have my notes handy but, going from memory, my 500g cylinder was 2.3kg empty and 2.8kg when full.

Hope that helps.

JPC


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## Nick72 (1 Jun 2020)

jaypeecee said:


> Hi @Nick72
> 
> Yes, my 500g cylinder is refillable.
> 
> ...




Going off thread a little here, but I'm suprised your 500g cylinder weighs 2.3kg empty.

That's the same empty weight as my 3 liter (3Kg) cylinder.


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## jaypeecee (1 Jun 2020)

Hi @Nick72 

I've just dug out my CO2 cylinder. It's a JBL Pro Flora m500 and it weighs 2.3kg empty. The cylinder is made from a magnetic material as magnets stick to it. I would guess that it's steel. I have now found a suitable link:

https://www.jbl.de/en/products/detail/7372/jbl-proflora-m500-silver

You would appear to have an ISTA cylinder. This one, perhaps:

http://www.istaproducts.com/product/co2-aluminum-cylinder-3l/

The ISTA cylinder is made from aluminium/aluminum, which is obviously going to be a lot lighter than steel.

JPC


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## Nick72 (1 Jun 2020)

jaypeecee said:


> Hi @Nick72
> 
> I've just dug out my CO2 cylinder. It's a JBL Pro Flora m500 and it weighs 2.3kg empty. The cylinder is made from a magnetic material as magnets stick to it. I would guess that it's steel. I have now found a suitable link:
> 
> ...



I did wonder if it might be steel knowing that mine is aluminum and lighter than steel.  Still surprises me that a 500g capacity steel cylinder weighs as much as a 3Kg capacity aluminum one.  

The wondrous weight saving of ali then.


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## jaypeecee (1 Jun 2020)

Nick72 said:


> I did wonder if it might be steel knowing that mine is aluminum and lighter than steel. Still surprises me that a 500g capacity steel cylinder weighs as much as a 3Kg capacity aluminum one.



Hi @Nick72 

Steel would appear to be approximately three times denser than aluminium/aluminum. But, then, there's the cylinder wall thickness to take into account and we don't know that. Nor do we need to. The figures speak for themselves.

JPC


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