It's been a couple years since I did any aluminum but I went to the shop to do an aluminum tig job (simple inside corner) on the Miller Shopmaster 300. It has a MIG feeder and a TIG HF unit (and I could hear the HF) on it. Has a bottle of Argon that was running about 50CFH. I verified gas coming out of the TIG torch and reduced it to around 20 before I struck an arc.
The shop owner told me that about a year ago the capacitors blew and he sent it out for repair. The LWS sent it to W Va (Miller repair depot) for repair and it worked when it came back. Then later on, it simply stopped welding and he hasn't been able to get it to work at all.
I tried it and the tungsten was sharp and all work was clean.
I set the amperage at about 100 amps AC and attempted to strike an arc but only got a rough arc. I was finally able to get a puddle but the arc was still EXTREMELY rough and unstabe like it had no gas. The tungsten melted and the cup got red hot and cracked.
I was at no time able to make a good puddle as I've done with other welders and what little I was able to do was simply CHEWING GUM.
Does anybody have suggestions ?