Welding Gas Volumes Confusion?

[agent_zed]

HI,

so i managed to let all my argon out of the disposable bottle the other day due to an ill fitting pipe (gonna glue it in this time) which was rather annoying and a waste of £10

 

So i got to thinking whether it was time to buy bigger bottles anyway.

 

I am confused though over the volumes/weights for example

 

10ltrs here is £35 (+£50 deposit) and is a reusable bottle which i assume is relatively big

http://www.weldinggases.co.uk/index.php?_a=product&product_id=2

 

but a 110ltr disposable bottle from machinemart for example https://www.machinemart.co.uk/shop/product/details/argon-gas-cylinder-2 is £15.59.

 

Now i know that the top one must be far more gas and won't be 10x less that the small bottle as there wouldn't be more than a puff in a can. So what is the difference in the way it is measured and how can i compare the values so i know relative costs.

 

 

second question can i weld everything with argon? if its cheaper to buy a bigger argon bottle than disposable CO2 then i'd just use argon. I know CO2 would be cheaper if bigger as well but then i'd have 2 rental bottles.

 

thanks

[Guest 2b cruising]

The refillable larger bottles measure in high pressure form where the gas has turned to liquid.

The disposable ones do not load under such a high pressure so measure in the gas form.

This means if you let all the gas out of a refillable, the one you gave an example of would fill a 110 ltr paper bag. Or empty space at sea level. Or 1 bar.

This is not much at all.

All gasses change to liquid under enough compression.

Cannot remember welding bottle pressures of hand but it is a vast amount in comparison to throw away bottles.

Throw away bottles would not withstand anything like the same pressures.

H T H

[agent_zed]

so i'm not sure if this is correct but on the first link it says

 

Approx. Nominal Contents - 2,1m3 (I am assuming that the , should be a . so 2.1m3 ).

 

1m3 = 1000 litres so 2.1 is going to be 2100 litres. Can that be correct?? as that is a lot more than the 110litres of the disposible bottle if so and is well worth the money

[Guest 2b cruising]

A

Edited June 19, 2015 by 2b cruising

[sj-bradley]

 

All gasses change to liquid under enough compression.

 

 

Not quite true. Helium for example will only turn to liquid when cooled below 4 Kelvin (-269 degrees C) and will not turn into a liquid by mere compression at room temperature.

 

and CO2 turns into a solid when rapidly decompressed (also cools rapidly) and solid co2 sublimes straight from the solid to the gas without going to the liquid form in between.

 

This is what I remembered from my schoolboy chemistry anyway as co2 or "dry ice" is a good party trick to make smoking cocktails ...

 

Simon.

[Snapperpaul]

10L bottle when I was Scuba diving was a small bottle but still 2 ½ foot tall 6 to 8" diameter

The 12L was used for most dives, I did have a 15L but it was huge.

 

Each extra bar of pressure over atmospheric added the same volume of gas available again

We ran 207 & 232 bar that's a lot of gas

[steve in stockport]

The cylinder capacity is measured in a couple of ways. There's water capacity which is what gives you the 10 litres for the refillable cylinder that you have linked to. Then there is the compressed gas capacity which is the water capacity multiplied by the cylinder pressure. In this case it's 200 bar or 200 x atmospheric pressure.

So 10 x 200 = 2000 litres or 2 cubic metres of gas.

The 110 litre disposable bottle will be something like 1 litre water capacity at 110 bar.

[Grim]

The refillable larger bottles measure in high pressure form where the gas has turned to liquid.

 

Not according to the gas safety course i was on last month!

[agent_zed]

even more confused now. So started reading about the shielding gas options and realised that i have probably been using the wrong gas anyway. From what i read for stainless i should be using Argon/CO2 mix.

 

so i looked up AR/CO bottles and the one on machinemart is 86% Ar and 14% CO2 but reading on this page http://www.lincolnelectric.com/en-gb/support/welding-solutions/Pages/compact-welders.aspx says not to use pure argon and not to use a mix that has more than 5% Co2 ?!

 

So do i stick with pure argon or go for a ArCo mix that has more than the 5% recommended Co2 that the article above states?

[Guest 2b cruising]

Some people use normal argoshield.

This has an even higher amount of co2 mix.

I know a high rate of argon is recommended for aluminium welding but one sure about stainless.

If you try it with argoshield to start with and it proves useless, the remaining gas will not be waisted as you can use it for mild steel welding.

I would suck it and see. If penetration and serface finish hole free, use the much cheaper argoshield.

Some people even use mild steel wire, but I would not recomend this.

Edited June 21, 2015 by 2b cruising

[agent_zed]

from what i understand if you use too much c02 in the mix it reduces that corrosion resistance in stainless. I guess it's not a huge problem as it's only an inlet manifold for my bike carbs so a bit of discolouration isn't going to hurt and it's not out in the rain. might give a mix a try and see how it welds. Got stainless wire for stainless as it adds extra chromium and nickel to the weld from what i understand.

 

thanks

[chris n]

Don't bother messing about with the disposable bottle anymore as they don't have much weld time

and always run out in the middle of a job when every where is closed

 

Now use a 5% CO2 / Argon mix from Adams Gas bottles are rent free all you do is pay a deposit for it

and when you don't want the bottle anymore you get your money back.

Was using the 9 litre bottle which works out at £85 +VAT for the deposit and gas and £30 +VAT for the refill.

Have swapped over for the 20 litre bottle at the end of last year which is £138 +VAT and £58+Vat a refill.

I use the MIG most weeks and the bottle is still over half way full, so it a no brainer to me.

 

http://www.adamsgas....t&view=category

Edited June 21, 2015 by chris n

[agent_zed]

the bigger bottles need a different regulator don't they?

[tractor]

welded my exhaust with stainless wire and argon mixed co it hasn't rusted and did quite a few miles in the rain yesterday

[chris n]

the bigger bottles need a different regulator don't they?

 

Yes they are different, standard BOC fitting, you can pick a good regulator for want you need for about £20 on E bay