Stamos Tig Polarity

[Pete Appleton]

I hope that I am doing something wrong with this machine but I can't see what. We have a Stamos ALU220 Inverter TIG welder. I have never used it before but I am assured that it has always worked ok on aluminium. I don't know if it has ever been used on DC. Whenever we try to weld steel sheet, on DC, the electrode burns, there is a load of flare and we never get a weld pool.
There is an old dinosaur of a TransTig machine in the corner at work and, whilst I am no welding artist, I can weld steel fine with that so I don't think that it is just me.
If I put an inductive ammeter on the earthing clamp line of the Stamos welder it indicates flow passing from the earth clamp back to the machine. That sounds like DCEP to me. On the TransTig it goes the other way.
What am I missing? There doesn't seem to be a switch for this setting. Has something gone wrong or does it sound as though it has been wired up wrong from new? A quick look inside shows that all of the main conductors are solid bars that cannot easily be transposed. I don't particularly want to send a pulse of HF up my multimeter.

 

[Fazerruss]

Are you sure you are getting gas to the torch? If so try swapping the earth clamp and torch connections over.
Does it weld ok on AC 50% balance?

 

[Pete Appleton]

Yes. Gas coming out of the torch.
It welds ok on AC. You can even weld steel on AC but it isn't nice.
You can't easily change the connections over. The gas goes up the same connector as the power and the HF injection is on the inside of the torch connection. I suspect that I would end up with an HF work bench.