At what pressure to replace mig gas bottle

[kencunningham]

I am just about thru the first bottle on my HH 190. This is the first time using gas, and was wondering at what pressure i should switch it out.

 

[rsallen]

Shrug,
Before I obtained a second bottle I would wait until I'd be worried about running out in the middle of a doing something.

By now you should have a bit of a feel for how much you're using. Are you getting nervous? Change it out or buy another bottle. What do they need for a bottle these days? The last I knew they wanted around 50 bucks to own a small bottle plus whatever gas you needed.

Do you trust your gauge reading?

 

[kencunningham]

I have 2 bottles, i was looking for other peoples experience to help me decide how low to let the pressure go before swapping it out.

 

[Shield Arc]

On my Mig gas I run it down until the working pressure starts to drop. I run between 15 to 20-cfh.

On my argon bottle for Tig welding if I'm doing aluminum work I'll switch bottles sooner. For some reason when doing aluminum Tig work, soon as the bottle gets close to empty it affects the weld.

 

[Stimw]

I run mine down until I start to see porosity (bubbles) in the weld with my 75/25.
I have a CO2 back up bottle (soft drink tank) that I will use to keep going.
For me it's 2 hours round trip for a fill so I have to plan the trip.

 

[JCByrd24]

Agreed if you have two bottles you do not need to change it before it won't weld right. You will know right away.

 

[Mark @ Everlast]

I run it till it's empty..especially if I am doing it on my dime. You can stop once in a while to readjust the regulator if need be if it's running it's last gasps...unless it's a super critical weld.

 

[Arc weld]

How big are your cylinders? Running it till empty means you'll probably have to grind out a bad weld and if you don't completely grind all the weld out, you'll get porosity and have to grind it out again. Depending on the weld could be a real PIA. Run it down to around 40 PSI or so and you shouldn't have to worry about a bad weld. 40 PSI is a lot more gas in a big cylinder than a small cylinder. Adjusting the regulator may or may not do anything but I've seen a few people turn their oxygen or acetylene up trying to get more gas from an empty cylinder and then forget to turn it back down when they get a new cylinder. This can be dangerous and/or waste a lot of gas. It's always best to loosen off the regulators every time but on a flowmeter/flowgauge, it's very rare to back off the adjuster.

 

[kencunningham]

Both of the cylinders are 40cf. After seeing the responses, I'll only let it go down to 50 psi at the lowest.

 

[bbt82z]

50 psi will get you a lot further than you think. You do not need to worry about you the psi in the tank until you see that the tank will no longer produce the pressure to desired CFM you set. Once you have used a few tanks you will know, roughly, how big a job you can do with what psi you have in the tank. I have two tanks. I ran out once, on a saturday, (the gauge was not working properly) and I will never do it again.