Is my welder tank leaking?

[Fender1325]

I have one of those smaller 40 CF tanks I use on my welder - 75/25 with my hobart 140 and .030 wire. I set it at about 20 CFH.

My last tank lasted me atleast 3 months. This one lasted me about 4 days. Granted Ive been doing a lot of welding but damn!

I feel like my last tank when new reached 2000 psi when I opened it. This recent one only reached about 1800.

I use the smaller rolls of wire.

Does it sound normal for a 40CF tank to last 1 small roll of wire? I feel like I got ripped off or I have a leak but maybe I just did a shitload of welding.

 

[malibu101]

I have one of those smaller 40 CF tanks I use on my welder - 75/25 with my hobart 140 and .030 wire. I set it at about 20 CFH.
.

Simple math- 20 CFH with a 40CF cylinder equals 2 hours on trigger on time.
Did you weld for about 2 hours? That is the answer to your question.

 

[BD1]

Running at 20 CF a 20 CF tank will last about one hour, a 40 CF two hours of welding time.
As a reminder on 75/25 tanks , it is best to open the valve fully, BACKSEATED, or you could lose gas through the tank shutoff valve. Some tank valves may leak if not fully opened. You can check for leaks with soapy water like Dawn and water mix and brush or spray on fittings,hose, and valve.
Welding web is a great site for more info.
http://weldingweb.com/showthread.php?13586-20cf-or-40cf-cylinder
http://weldingweb.com/forum.php

 

[bad_idea]

Check that your machine is stopping gas flow when you release the trigger. I have the Hobart 185 and have had issues with the gas continuing to flow after the trigger is released. It turned out to be the contactor had grinding dust in it. Disassemble and blow the machine out fixed it.

 

[pepi]

40 CF tank, not up to the job, wasted money and time running back an forth for refills.

 

[Fender1325]

Simple math- 20 CFH with a 40CF cylinder equals 2 hours on trigger on time.
Did you weld for about 2 hours? That is the answer to your question.

Its tough to say. Ive been doing a lot of stitch welding sheet so the trigger has been on and off for a second or two every time. For that to add up to 2 hours would be surprising to me.

 

[Fender1325]

Check that your machine is stopping gas flow when you release the trigger. I have the Hobart 185 and have had issues with the gas continuing to flow after the trigger is released. It turned out to be the contactor had grinding dust in it. Disassemble and blow the machine out fixed it.

How do I test if its still flowing after I release?

 

[Fender1325]

Running at 20 CF a 20 CF tank will last about one hour, a 40 CF two hours of welding time.
As a reminder on 75/25 tanks , it is best to open the valve fully, BACKSEATED, or you could lose gas through the tank shutoff valve. Some tank valves may leak if not fully opened. You can check for leaks with soapy water like Dawn and water mix and brush or spray on fittings,hose, and valve.
Welding web is a great site for more info.
http://weldingweb.com/showthread.php?13586-20cf-or-40cf-cylinder
http://weldingweb.com/forum.php

I always open it all the way until it stops turning. This tank also had a knob that was much harder to turn compared to the first one I had at airgas.

 

[383 240z]

you mat be able to hear it, if not small jar with water in it. Just put the tip in. I cant believe I just said that

 

[george4]

, it is best to open the valve fully, BACKSEATED, or you could lose gas through the tank shutoff valve.
http://weldingweb.com/showthread.php?13586-20cf-or-40cf-cylinder
http://weldingweb.com/forum.php

Good rule for welding gases except for acetylene which you want to be able shut down quickly.

 

[maxpat82]

a 55cf tank wouldn't last long with my tig. each time you touch the pedal for a fraction of a second it's 2,5s of gas flow (,5 pre flow, 2s post flow..and they are set short)
a simple tack is around 2-5sec.(+pre and post flow)

It goes quick!!! I changed to a 125cf tank and it's really still not big enough.. But I need to modify my cart to allow me to put a 300cf tank on.(didn't build the tank seat big enough)

CF/$ wise: the bigger the tank ..the cheaper it get. (my 55 was costing me like 75$ when the 125 is 90$ and a 300 is 140$) (Argon is pricey here )

 

[Fender1325]

you mat be able to hear it, if not small jar with water in it. Just put the tip in. I cant believe I just said that

Hahah. So I can get a jar of water, turn on the machine, dip the tip in and squeeze the trigger while running? and not blow up my house and machine?

 

[fnieto]

You should always check for leaks reguarless to tank size. I do this by hooking up the tank, open the valve and read the tank pressure gauge. Turn off the valve and the pressure should remain steady for a few hours. I have had bad tank valves in the past leaking from the threaded portion to the tank. Windex or mild soap solution show this. I only have large K bottles.

 

[bad_idea]

Pull the trigger, let go of trigger. Put nozzle NEAR ear. Listen for gas flow. If the contactor is sticking it will stick open or closed, no partial open. If it is sticking, the wire may still be energized. Thats why I said NEAR ear, you could zap yourself if you touch your ear. I wouldn't stick a welding nozzle in water, sounds like an accident waiting to happen.

 

[BD1]

Good rule for welding gases except for acetylene which you want to be able shut down quickly.

Yes, that is why I specifically SAID 75 /25 . You gotta be careful what you write on the internet. I only crack the oxygen a full turn.
Pure argon is the same , some tank valves do not leak if cracked open while others do.

 

[dr_clyde]

Acetylene cylinders are only single seat so they can be closed quick. They are also comparatively low pressure. About 350 psi. High pressure cylinders, argon, O2, co2, all are double seat valves and run 2300 psi, which in turn may cause leaks around the valves if not seated right.

In this case, I bet you just used it up welding. 40 cf won't last long, even if stitch welding.

 

[383 240z]

Hahah. So I can get a jar of water, turn on the machine, dip the tip in and squeeze the trigger while running? and not blow up my house and machine?

Yes under power, no not with the trigger squeezed. Your not looking to see if the gas is flowing while welding, your looking to see if the gas solenoid is sticking on, allowing the gas to flow after the weld.

40cf is a REAL small bottle. I think the 80cf on my MIG is a bit small. The 125cf on my tig is almost too small. No I don't run a production shop. Keith

 

[Nor'Easter]

I always close the knob on the bottle when not in use. Even if I may be welding again in an hour...

 

[Fender1325]

Cool. Thanks guys.

 

[zak77]

One thing i noticed about my 140 is that it'd leak gas if the tank was open and not using the machine. Good way to test this shut off the gas and machine then check the pressure gauge in about an hour. Mine would be be close to 0 psi after an hour. My new 210 mvp is still around 2000 psi on the gauge even after not touching the machine in 2 weeks. I learned quick to shut off the tank with the 140 when not in use.

 

[383 240z]

So OP, what did you find?

 

[Fender1325]

Nothing yet, had to get a project done for christmas and didnt have time to get to airgas for more gas so I just used flux core.

From my post on a weld forum though, the rate I used the gas up was pretty normal. Also temperature can effect psi totals so in the summer I guess 2000 psi from a 40 cf tank is average vs the more recent 1800 I experienced when first opening the new one.

 

[bad_idea]

Soooo...... I HAD to revive this old thread. Had to. I was welding tonight with my Hobart 185 and the gas is flowing after I finish a bead. I web searched the issue and found this thread. The thread where I responding saying I have had the issue and solved it by blowing the machine out.

I haven't had the issue for nearly 10 years now. Completely forgot I ever had the issue. It was like the first time all over again. Guess I'll be opening the machine and blowing it out next time I go out to the garage. I fear I may be losing it.

 

[OccupantRJ]

 

[Spareparts]

Back 1973 I worked as a maintenance Mech for a Machine Shop/Production Welding Shop, fist thing in the morning
I filled CO2 bottles, about 20, there were the size of a regular oxygen about 5'tall. They would last about 6-8 hrs.
before changing out. This was not a production line of continuous welding, about 5-6 hrs of actual welding.