Thread: Are you worried about leaving your gas bottles on?

This probably one of the most useful things I've done so far this year.

Call me paranoid but I can't bear the thought of losing the contents of a gas bottle so I rigged up this pressure sensor to close a switch when it's under pressure and light up a multi-coloured blinking LED.
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I made up a T-piece from a piece of brass rod (that's the chunky size pice of brass under the flow meter) with the press sensor (black rubber boot) hanging off the side. The pressure sensor is adjustable and is set to fire off at about 0.5 atm. The led is mounted on th front of the grey electronics box held by a 3" hose clamp onto the neck of the gas bottle and powered by a 12V walwart and it certainly gets my attention. No good for portable set ups but good for my stationary welder arrangement.

Nice work.
I just religiously turn off the gas at the end of the day ... or even if there is a decent length break in the welding process.

Funnily enough, I can come back to the cylinder a couple of days later and the reg is still pressurised from it's last use ... so no significant leaks.

When I started welding in the 1970s I was always taught to depressurise the regulator(s) when not in use and have done that with my own kit for the last few decades, but at a place where I do some welding jobs they just turn the bottle valve off and leave the regulatours under pressure. Now I'm beginning to wonder what others do and what is the "right" way.

I always release the pressure from the gauges supposed the to extend the life of the gauge

I never release the pressure and I've not had to replace any of my regs (they range in age from 10 to 20 years old), but it's not like I'm welding every day or anything.

So maybe for the hobby welder at least, it isn't really a big issue???

Originally Posted by Vernonv

Nice work.
I just religiously turn off the gas at the end of the day ... or even if there is a decent length break in the welding process.

Funnily enough, I can come back to the cylinder a couple of days later and the reg is still pressurised from it's last use ... so no significant leaks.

Exactly the same for me. It would be a real bummer to realise a G cylinder of gas just drifted of into thin air one night.
I'm religious about gas valves and powerpoints after each shed session.
- Mick

I thought I was pretty good when it comes to closing the valve - it's right next to the switch on the back of the machine, so both go together. However I've recently been running some rods with it (it's a combo machine) and having forced myself to stop turning the gas on, thus breaking that habit, I then left it open after I did some more MIG work. When I discovered it still open and pressured up today I was kicking myself - I'm hoping I haven't lost too much

Are you using a pressure switch or a pressure transducer? Got a link to where you sourced it?

Originally Posted by RustyArc

Are you using a pressure switch or a pressure transducer? Got a link to where you sourced it?

It's a mains water press switch that is easily adjustable to switch on between 0.5 and 10 bar. Before I added the switch I put a pressure gauge on in place of the switch to check the pressure and it showed ~40 psi so I've set to trigger on minimum.

The switch was from an Ebay. Sorry can't provide exact source as my pc is down at the mo and am running off this crummy ipad that won't load eBay.

Computer now workings: link is Normally Open NO Normally Close NC Pneumatic Adjustable Pressure Switch | eBay

Ive had this happen. Brand new e argon. less then a minuit use. Only used to tack. Left it on overnight next morning empty. $160 gone.

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I lost 5 of a 6kg CO2 bottle a few weeks ago.
It was a bottle I use for my Soda Stream machine and had disconnected from the Soda Stream line that reaches under the house and had free standing in the shed.

I came into the shed a couple of mornings later and found a lot of condensation around the valve and a pool of water on the floor around the bottle. A quick investigation must not have closed the valve tight enough,
A leak monitoring setup like mine wouldn't have helped as I would not think of using it on a free standing bottle.

Have since though that putting a balloon over the outlet which means if there was a slow leak it would show up fairly quickly.
At least it was not argon.

Correct procedure is to shut down cylinder valve always, then back off the regulator.
Then observe regulator gauges any drop in pressure of hp gauge indicates a hp leak and any drop of lp gauge indicates a leak on the low pressure side. I both gauge drop in pressure you possibly have a bum regulator.
Also when opening a hp valve on a cylinder all gauges should be backed off to avoid shock to gauges and main regulating seat.

Originally Posted by millalot

Correct procedure is to shut down cylinder valve always, then back off the regulator.
Then observe regulator gauges any drop in pressure of hp gauge indicates a hp leak and any drop of lp gauge indicates a leak on the low pressure side. I both gauge drop in pressure you possibly have a bum regulator.
Also when opening a hp valve on a cylinder all gauges should be backed off to avoid shock to gauges and main regulating seat.

This will pick up any major leaks but some leaks may be so slow it may take many minutes or even hours to see a change in gauges. And it does not really help if the cylinder is not switched off.

The problem with the CO2 bottle that attaches to the Soda stream machine is there are no proper gauges on it, There is a special HP connector with a 5c sized HP gauge that basically shows if the cylinder is full or empty, and then a fixed regulator before the going to the machine. I should probably buy a reg for it then I would at least how full/empty the bottle is.

I've always turned the cylinder off and then released the gauge. The clown I used to have working for me, his idea was to turn the bottle on fully when finished for the night. I only found out one morning when I went to do some welding and it was fully on, he thought that was the way they closed.
Looks like a handy device Bob.

I just finished some welding and was outside grinding, earmuffs on. When I came back in I found that the gas line connector to the back of the welder had popped off (clamp and all) and my gas was blowing away all the time I was grinding.
Ironically, I almost always turn off the cylinder valve after each bout of welding, but consciously didn't this time as I had planned to do a few more runs after cutting some more steel.