How much C02 left in tank

[nashvillebill]

The CO2 tank that came with my "new" HH175 shows around 500 psi or so on the gauge. This is (I think) pure CO2. The tank measures exactly 8 inches diameter by 46 tall (not counting valve).


Searching on the 'net hasn't resolved my question: how much gas is left in my tank? This tank size doesn't seem to correlate with any of the tank sizes listed on the charts I've seen.

thanks in advance!!

[Zrexxer]

Nearly all of it... or nearly none of it. The vapor pressure of a gas compressed in a liquid phase like CO2 reads pretty constant regardless of the level. Its probably affected more by temperature.

[nashvillebill]

So I guess I just keep welding until I don't hear any more gas and the welds look (even more) rough....

[jeepnjim]

co2 is sold by weight. there should be weights stamped on the bottle that will tell you how many pounds are left in the bottle if you weigh it.

[nashvillebill]

co2 is sold by weight. there should be weights stamped on the bottle that will tell you how many pounds are left in the bottle if you weigh it.

It's an old bottle, there's numbers stamped all over it, I haven't been able to decipher anything yet.

[Tom37]

If it acts like mine then it will run with slight drop and then all of a sudden it will drop fast. Most likely while you are 3 or 4 welds away from finished. This fact of running out during a project on the weekend is why I have a #20 bottle of co2 in the corner waiting.

[Roger]

1 pound of liquid CO2 will expand to 8.8 cubic feet at 1 ATM.
Your tank probably has no liquid CO2 in it unless temperature is less than 30F.

http://www.teamonslaught.fsnet.co.uk/co2pv.gif

If I knew internal volume of tank easy to calculate amount of gas.

Below 100 psi to 25psi cylinder pressure regulator will stop supplying set flow rate.

[snoeproe]

Notice the pressure gauge on your regulator right now.
One day you will be welding and you'll notice a reduction in shielding gas flow. If you check your pressure gauge on your regulator when that happens you will notice little or no pressure left in the bottle. It's as simple as that. Keep on welding till that day happens and when it does, it's time for a refill.

[gatemaker]

I use the old 330cuft cylinders that come with 50# in them. You can do a lot of MIG welding before the cylinder drops to 300# or so. 300# to empty might only be a couple hours of 25-30 cuft/hour welding.
This didn't answer your question, but you get the idea about a slow drop, then a sudden quick drop in pressure. Go ahead and use it until you get porosity.

[Roger]

I worked in bar using CO2 tanks for soda gun for mixer, soda fountain and keg beer. Lifted tanks to check when they were nearing empty and pressure gage when they were really close to empty. You can easily tell by lifting tank when it is full, 1/2 empty or near empty 1/8 tank. Having reserve full tank takes care of surprises. CO2 paint ball tank might be all that's needed for hobby welder reserve tank.