Welding gas consumption

[67mater]

I rented and filled a very large gas tank when I borrowed my uncle's MIG. I don't know off hand how big, but it's probably 4' tall and 10" in diameter. Annyways, it was around 150lbs of pressure when I bought it. I didn't change any settings on the regulator as I get great welds out of it. When I was done welding the cab (never leaving the tank valve open over night or anything; it is an old mig and likely leaks) I was all the way down to 80lbs. Is that reasonable? What I was seeign was a few lbs drop over night with valve shut.

I went to use it today and it's at 25lbs. VALVE SHUT!!! what gives? I tried soapy water on everything but see no hint of leak (tank valve, regulator, hose etc.) I didn't check the pressure until after I had done about an hour of spot welding, but how fast will a large tank run out? is it conceavable that the tank should drop 10 lbs eveytime I really use it? and any shot of complaining to the shop I got the gas from? or do I have to spend $300 more to fill it again? (which I won't as I have a flux core for the little bit of body welding I have left right now)

[cdowns]

150lbs aint much // all the tanks i've had were like2000lbs full//what valve was shut the oine on the regularor or the one on the tank? how many gauges are there on the regulator?

[67mater]

I'll have to double check what the gauge measures, perhaps it was 1500. Anyways, i always shut the valve on top of the tank when I was done welding, which should stop the tank from losing anything, which is why I don't understand why when I open it back up the gauge would show less than it did the night before. There is a gauge between the regulator and tank (this is where I am getting my pressure numebrs from ) and then a flaoting ball gauge on the regualtor that goes up when you are actually welding.

[jorgensensc]

What pressure are you putting out at the welds? Maybe your pressure out is too high and your wasting gas?
Shawn

[67mater]

possible, but doesn't expain how it's dropping when the tank valve is shut.

[jorgensensc]

Temperature changes? Does the pressure change with temperature increases or decreases?

[67mater]

interesting possibility, but yesterday and when I was welding the cab were both around 70 degrees.

I know the welder leaks, as the line will be down to 0 overnight, but what I guess makes me mad is why when the valve is shut the next day would read lover once opened AND that now I'm out of gas in a matter of months.

I suppose I'm SOL, and just glad 90% of the rquired wleding is done. Back to the flux core it is!! we'll see if my improved skills make that any better of a process.

[truckdude239]

maybe the vavle on the tank leaks too

[67mater]

is it my word against there's or can they test it?

[hdflstf]

You also need to be sure to open the valve all the way so you don't leak gas out of the top of the valve when it's open.

[67mater]

that I didn't know

[Custom 68]

There should be 2 gages on the bottle one for bottle pressure and like said it will be high around that 1500 psi or so. The second one is your welding pressure and should be around 5 - 8 psi. The gas will last a long long long time under normal conditions. I just filled a small tank 2 feet tall or so and it was around 20 dollars to fill 300 bucks seems a bit steep.
I wonder if they got it full?
Dave

[special-K]

It`s thier tank.They are required by law to maintain the equipment to standards,which is leak-free.You should call them and see what they`ll do.Say you suspected the gas was going fast,but when you got that low and it dropped overnight where you could tell.And,that`s why you just now are complaining at the end of the tank.

[Garagedude]

You paid $300 to rent and fill the tank?