Welding Tips and Tricks

I've been trying to find a slow leak in the argon supply of my AHP Alpha tig 200, since I got it 2 months ago. It was leaking much worse, but I got AHP to send me a new flowmeter, and now it is very slow. Here is what I did this morning to give you guys an idea of the leak. First, I never turned the welder on. I fully opened the argon tank valve, the ball jumped up for a second then back to bottom of tube (as usual), the pressure guage read 1500 psi. After a minute or so I clossed the tank valve tight. At this point, there is pressure from the flowmeter to the on/off solonoid valve in the welder (correct?). 4 1/2 hours later (thats when I remembered to check), the pressure was at 600 psi. The outside temp. had not changed at all during this time. Now I realize that the pressure is only dropping from the small area of the hose and fittings, but my Lincoln mig welder has the same pressure at the guage even 24 hrs. or more after clossing the valve. Because I can't find bubbles anywhere, when testing, I feel that the only place it could be leaking is through the valve. So I'm asking for opinions, am I loosing enough gas to make it worth pulling the valve apart (if it even comes apart) and (hopefully) fix it, or should I just live with it, and hope I never forget to close the valve when done welding?? Thanks for your thoughts, JR49

First thing, brush some water with dish soap on it to try and isolate where the leak is. It will be around one of the fittings, you will see bubbles where it is leaking. Until you find the actual leak you could be chasing your tail in circles. My $0.02.

Alan

Remove the flow meter from the tank. If the tank valve is leaking then return it for a replacement. The tank should NEVER leak.

cj737 wrote:Remove the flow meter from the tank. If the tank valve is leaking then return it for a replacement. The tank should NEVER leak.

Not sure what you mean by that cj. if the tank valve was leaking then everything up to the solonoid valve would stay preesurized until the tank ran out. And as I said in original post, I tested everything, including the tank valve, and found no bubbles up to the welder valve. Thanks, JR49

I assume you checked the output side of the solenoid, and the nut that screws into the tank. Did you paint the full length of the tubing with soap? Those tubes are some kind of plastic, so it could have a small hole from damage or a manufacturing defect.

JR49 wrote:

cj737 wrote:Remove the flow meter from the tank. If the tank valve is leaking then return it for a replacement. The tank should NEVER leak.

Not sure what you mean by that cj. if the tank valve was leaking then everything up to the solonoid valve would stay preesurized until the tank ran out. And as I said in original post, I tested everything, including the tank valve, and found no bubbles up to the welder valve. Thanks, JR49

If you tested the line and connections, it seems like what you're saying is that it's leaking inside the welder?

When you press and turn the welder on how much is the argon tank reading? Could you just have it set really high and not realize it?

Press the pedal/switch and see what the setting on the flow meter is.

Alan

Do you weld for long periods of time? If not seems like a minor concern as long as the tank is not leaking.

JR49 wrote:

cj737 wrote:Remove the flow meter from the tank. If the tank valve is leaking then return it for a replacement. The tank should NEVER leak.

Not sure what you mean by that cj. if the tank valve was leaking then everything up to the solonoid valve would stay preesurized until the tank ran out. And as I said in original post, I tested everything, including the tank valve, and found no bubbles up to the welder valve. Thanks, JR49

I am responding to your statement:

JR49 wrote:I fully opened the argon tank valve, the ball jumped up for a second then back to bottom of tube (as usual), the pressure guage read 1500 psi. After a minute or so I clossed the tank valve tight.

If you opened the tank valve, then closed it "tight", and your tank is leaking pressure, the tank valve is suspect. All leaks begin their potential there.

So either what you posted is not what you meant, or the obvious escapes us both?

Have you soaped up the rubber hose itself. Rubber hoses will become porous and leak. I replace my refrigeration hoses about 1 a year. Because after a midwestern winter and summer the rubber starts to dry out and will leak.

You can’t tell where the leak is because you haven’t removed tank pressure from the low pressure side of the regulator. Until you pressurize the line, then close the tank, THEN let the regulator knob spin out to free so you can tell if the tank side or the line side is leaking you’re not going to find the leak.