250EX very strange welding, was I given something other than pure argon??

[Gandalf]

Hello,

I have been welding with the 250EX for a year and half now, with flawless operation from the machine. My welding skills are progressing. I am mostly doing automotive projects, aluminum, with the occasional stainless. I never needed more than 120 amps up to this point.

I switched in a fresh bottle of argon today, flipped to AC, and tried to tack an aluminum throttle plate to a manifold. I got a weird discoloration, erratic arc, and no puddle. I grabbed a piece of 1/8" aluminum plate and tried to run a few lines to test things out. The arc was dancing around, making these strange tiny pits and circles, lots of black speckles and creamy-yellow discoloration beside the attempts at lines. I played with the amount of argon flow... it made no difference in the look of the outcome. The flow sounded and felt normal. The tungsten wasn't burning up, but looked black and shiny. Freq and pos/neg dials were about noon, also quite normal. TIG high freq start was fine. No pulse used. There is decent penetration.

This is what I am suddenly dealing with.... here's a pic:



I could be having a large brainfart (???) But I cannot figure it out. I really haven't needed to change much of anything recently besides flip the switch between AC and DC, and nudging the amps and the flow. And it's not how clean the aluminum is. This was set at about 80 amps, and a new tungsten.

Can the argon they gave me be something other than pure argon?

Any help much appreciated!
-Martin

[Rambozo]

Have you tried some steel?
It sure looks like a gas issue.

[everlastsupport]

Yea, best idea is check DC.

It's possible you have a bad tank, moisture (for CO2) in it. Can you ask the LWS to swap it for you. Seems like a pain, but it has happened.

Does the amp display max out at 250 when you ramp it up? Check the o-ring in the torch cap if you have remove the cap recently. When you open the tank and turn it back off, does it hold the pressures on the gauges until you bleed the lines?

[5440]

I was welding Al a week ago using the 250EX and ran out of Ar on one tank. We had an Ar tank for the spool gun that I tried. I started to get the pepper in the welds. Cleaned the metal and still similar results. So I got the empty tanked filled and welds seem ok....so as suggested, try a different tank.

[everlastsupport]

I was welding Al a week ago using the 250EX and ran out of Ar on one tank. We had an Ar tank for the spool gun that I tried. I started to get the pepper in the welds. Cleaned the metal and still similar results. So I got the empty tanked filled and welds seem ok....so as suggested, try a different tank.

Was the tank for a steel spool gun with aluminum wire or steel? It not aluminum wire MIX (4043/5053..) it is a mix of argon and CO2 and that would run hot and nasty for sure.

[performance]

Are you using a water cooled torch with a water cooler? It could be a pinhole in the torch gas line or a leak somewhere in the torch head as well.

[Gandalf]

I am just using the torch that came with the 250EX. The only way I could see a hole getting in the torch gas line is if it got a drop of melted metal through it somehow. I will check with stainless tonight and see if it also misbehaves then. Torch cap o-ring looks perfect. Can the torch have a "heat injury"? I really haven't cranked it up past 120 amps.

[everlastsupport]

I am just using the torch that came with the 250EX. The only way I could see a hole getting in the torch gas line is if it got a drop of melted metal through it somehow. I will check with stainless tonight and see if it also misbehaves then. Torch cap o-ring looks perfect. Can the torch have a "heat injury"? I really haven't cranked it up past 120 amps.

It is possible, but the torch is pretty tough. Why we ship it as a starter (and get killed on the complaints). And if you run 120amps or less, you are pretty much OK without a cooler if you know what you are doing.

[zoama]

Can the torch have a "heat injury"? I really haven't cranked it up past 120 amps.

If you were using the water cooled torch without water @120 amps AC, it may be damaged. AC puts much more heat into the torch.