[MWiener2]

I am a "pro" welder. I do performance automotive work and have been welding for over 10 years.

Recently ran into a new issue for me. Can't weld anything. Acts like something is contaminated.

My stainless welds are dark and pitted on the crown of the weld. Major issues with cracking. I get a lot of porosity and extended arc time only brings more contaminates to the surface of the weld.

Aluminum is even worse. Lots of black contamination in the weld. Gray crusty bubbles of aluminum. Just poop.

Started having problems on a low bottle of gas, down to 100-200psi. Figured it was the low gas and got a fresh bottle, but am continuing to have issues.

Machine is 4+ years old Miller Dynasty 280DX.

I have checked all the settings and they are my normal settings. Adjusting settings does not make anything better.
No gas leaks, flow is good. Adjusting flow has no effect.
Changed all the consumables on torch, no effect.

The only thing I can find that's not normal is my tungsten becomes discolored inside the cup. Screams contamination, but I can't find it.


Best guess right now is bad gas, but I know this is pretty rare. I would also expect much more obvious welding issues with bad gas.

Any ideas?

[Coldman]

If you have no leaks or flow rate issues and you've changed the torch parts then the only thing left is the gas. Time to change the bottle again I recon. I suspect this happens more than we really know about.

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[LtBadd]

Why would the last 3/8" to 1/2" be colorless, and the small band that would be inside the cup dark?

And with this ALL your welds are bad? Photos?

[Poland308]

What’s your cfm and cup size. It’s possible to get air drawn into the cup around the front edge if the cfm is too high.

[MWiener2]

All welds are bad on all materials will all different settings.
It's not a setup issue. I've been using the same setup for years and I just swapped out all consumables for new ones.

I'm really heavily leaning towards bad gas. This is the only explanation I can come up with for the tungsten only changing color inside the cup.

[77cruiser]

How about the torch itself? Is it a flex head? I had one that I couldn't weld alum, with (I'm no pro) change to a different on & welds great. Must have broke inside somewhere.

[tungstendipper]

Is your screen dirty?

[MWiener2]

Swapped out the bottle. All good now.

It was bad gas.