[DARCY]

I went to the local gas dealers during work hours to get a full argon tank. Back at work I start welding and there is black residue spotted on the weld surface and it must be getting inside the welds too. Before the refill the welds were getting along and clear.
I tried adjusting the gas flow up and down with not much of a positive outcome.

Any advice?

[robtg]

I had the same problem. The welding gas supplier tested the tank and found water contamination.

[Otto Nobedder]

Very likely.

Also possible, though less likely, is this was the first bottle filled after a run of 75/25, and they didn't purge the manifold, so you've got a little CO2 in there.

Either way, when the bottle is the only change, the gas is suspect.

Steve S.

[RedIron881]

I agree with the other guys. As side if the only thing changed was the gas... good chance its the gas. Just wanted to add something to watch out for when welding aluminum. Watch out for rod that is contaminated or has frosty spots on it. You want it to be nice and clean right out of the box. Can't tell you how many times I've bought rod straight from the store, opened it and it was covered in spots. If you're looking for nice clean mirrored welds these spots will drive you crazy! Now I open the box before I leave the store. Just something to keep in mind. Switch that bottle and let us know if it gets better.

[DARCY]

Not sure if the tank held 75/25 before?

I will definitely take a look into water contamination. Sounds likely.
Thanks for tips.

[Otto Nobedder]

Not sure if the tank held 75/25 before?

Not quite what I meant, but possible, too.

Argon bottles, CO2 bottles, and 75/25 bottles are usually filled from the same manifold, several at a time, with proportioning valves controlling what you get. If the operator just filled 50 CO2 or 75/25 bottles, and didn't properly purge the manifold before filling straight Argon bottles, the first bottle or two in that run will have some CO2 mixed in.

As I said, this is relatively unlikely, but possible, because the operator may have overlooked the step.

Moisture contamination is easy... If you get an exchange bottle, as most of us do, you have no way of knowing if the last user left the empty sitting outside with the valve partly or completely open. There are a lot of careless and/or ignorant people out there. In the weather, an open bottle will "breathe" with temperature and pressure changes, and accumulate moisture.

Again, it's on the operator to notice if a bottle he's hooking up arrived open, but those jobs don't have much interest or pay very well, so not every worker gives a damn about more than making his production quota.

Let us know what you find, please.

Steve S.

[DARCY]

I took the cylinder back today and got some new gas. Like a shining pearl the aluminum opened its kerf for me to see.
I have illuminated and pinpointed the problem thanks to the forum.

Most gracious
Darcy

[weldin mike 27]

Hey,

Great. Its amazing how nice it welds when everything is going good.

Mick