Problem With Mig Welder

Need some advice on a problem with our mig welder. My Son has owned his Miller Mig for a couple of years now, and has run probably 30 bottles of gas through it. It has been flawless. Yesterday we were starting to put together the new frame for Project $ 3K, and were low on gas, so we went to Northern Tool and swapped out the bottle. When we hooked it up and turned the valve to open it, a high pitched whistle started to come from the pop off valve at the bottom of the regulator. Also, the gauge that reads flow pegged. Three days ago the welder worked perfectly with the almost empty tank.

After fooling around with the thing for a while, we decided the only different thing we had done was changed tanks, so maybe the tank was improperly marked and had pure argon in it rather than an argon/carbon mix, so we went back and they exchanged it, but new one did same thing. We disassembled the regulator, and everything seems to be ok, we did blow out some very small specks of dirt, but nothing seemed grossly wrong. Put it back together, and it still whistles, and pegs the gauge.

We think the regulator is just worn out, possibly, but are suspect of the 2 tanks we got from Northern, because I exhanged my acetyline tank also yesterday, and when we hooked it up it was empty, even though it had a filled sticker on it.

We fear that the people who filled it might have put pure argon in by mistake, but thought someone on here might know what is going on. We have always gone to a welding supply company before this time, but they were closed on Sunday.

Thanks,


Don

Couldn't begin to guess how many bottles I've used, but never had a regulator problem. I'd have to find the paper work but I know its every bit of 20 yrs old. I think I'd wait and get a bottle you can trust.

Yeah the regulator is equipped with a pop off valve that prevents you from using high pressure bottles (those pressurized above 2500psi). Sounds like regulator blew out or someone over presurized the K bottle. Take the bottle and regulator back to Northern and have them check out both of them. Sounds to me like the pop off valve is doing its job. If you've run that much gas through the regulator it probably needs to be replaced or rebuilt anyway.

Yeah, I'm a little leary of Northern now, especially in light of the supposedly full acetyline bottle that was stone dead. Who knows who is filling the bottles for them, could be someome just starting out.

The regulator is actually pretty simple inside, and the pop off valve and diaphram look ok.

We planned on doing some welding today, but looks like that plan is scrubbed.


Don

I saw someone where I work over pressurize a device one time because the stem on the regulator wouldn't fit the bottle he was trying to connect to, so he took another regulator apart and put that stem in the low pressure regulator. Little did he know he was connecting a low pressure regulator to a 6kpsi bottle. He blew it off the test stand and completely through a sheetrock wall about 40 feet away.

That is my fear. These bottles are nothing to mess around with, and I don't want my Kid hurt. I am going to head over to the shop pretty soon and hook up another almost empty bottle and see what I get there.

I've seen some very dumb things happen to products if they put the wrong or new guy on the assembly line. It just seems very strange to me that this mig has always worked flawlessly, as recently as 3 days ago, and it suddenly goes at the very same time we change bottles.

If it is a regulator I will just buy one Tuesday when the welding supply opens, but I am just not convinced that the Northern bottles aren't flawed. The kid that helped us was nice, but had no idea what he was doing, and the refilled bottles were painted nice, but didn't have the protective caps in place in some instances. At least at the welding shop that is all they do, so they have a better handle on it, I think.

Really appreciate the replys. I respect this kind of stuff that can blow holes in walls.


Don


PS: Have a nice Holiday everybody.