[rahfish]

Folks,
New TIG welder, very old stick welder---I am in the process of setting up my first TIG machine and have a question about allowable argon gas depletion/leaks.

I have hooked up my new bottle of argon to my new TIG unit. At the end of my first test welding, I had 2100 psi remaining. I closed the hand valve on the tank and went onto some other chores. In about an hour, I checked the pressure and it had fallen to 1900 psi. I got out my soap/foam bottle and started leak checking all the fittings, regulator & attachments, and the solenoid in the machine. I could find no leaks/no bubbles. Also, all the equipment and bottle had been in a room with even temperature.

Over the next hour, the regulator and connecting tubing lost 200 more pounds of pressure. It finally settled at about 1000 psi this morning.

I know this is a very small volume system, but to me, this seems like a lot of pressure loss. Certainly a lot more than I ever had on my oxy/acetylene rig and hoses.

Does this amount of pressure loss seem normal for an argon gas system?

Thank you in advance for your assistance and info---RA Hall

[Otto Nobedder]

Welcome!

This is perfectly acceptable. You must realize the volume charged to 2100 PSI is the tiny space between the bottle's valve and the regulator's diaphragm. 5cc tops. You aren't losing a volume of gas you can put a monetary value to across a year, it's so small. You use more gas in a quarter-second of pre-flow.

Steve S

[exnailpounder]

My regs do the same thing on both of my welders. It is normal. Now if you turned the valve back on and you were down 1200 psi, then you have a problem. Welcome.

[Keith_J]

Same here. The tank valve is the likely leak spot. When open, the stem seals by compressing the packing against the gland nut. When closed, there is no compression of the packing.

This being said, mine was leaking last cylinder exchange and soap showed it was from the tank-regulator junction. I applied some pure MoS2 powder to the joint and burnished it in both the threads and the spherical sealing plug. This allowed a bit more contact force on the metal to metal seal. No more leak

MoS2 powder is from a bullet coating kit. Yes, I'm a gun nut too. Making holes in distant sheets of paper calms me nerves. Don't judge.

[mcostello]

Some valves have a back side seal. The knob needs to be unwound to compress the seal on the back, doesn't need much. See if it helps.

[C. Livingstone]

Yeah,

When I first set up my TIG unit and Argon tanks, they did about the same, which I never worried about, as I've always promptly closed the valve, even for bathroom breaks, etc.

But I did get around to putting teflon tape at all fittings below the regulator and up to the solenoid.

Now when I close the tank valve the pressure at the regulator stays almost perfectly steady for about a week or more.

[Olivero]

Yup, I loose my pressure after closing the valve in a couple of hours, if you want an idea of quantity, turn it on, do your thing, turn the valve off and then unhook the hose from your welder while its pressurized, as you unscrew it you will hear the hissing and if you manage to get it all the way off before its depressurized you will hear the last of it fly out. Its a really small amount, nothing to worry about. You could teflon everything up if you want to and try to eliminate it as much as you can but I just don't bother.

[rahfish]

My sincere thanks for your timely and helpful advice.

It seems I have a small problem that I could improve with some teflon tape and some time on a cold rainy afternoon in the northwest.

Thanks again and wishing you all a great holiday season and a very Merry Christmas---R A Hall