Using a Miller Diversion 180 TIG unit, I am filet welding (inside corner) 3/16 mild steel plate to a piece of 16gauge mild steel tubing. I am plugged into a 220V 20amp circuit and have my amperage set to 150Amps, "Steel" is selected on the machine. I have over 1,000LBS of Argon in my tank set at 13-15cfm and I can hear the valve open and close when I activate the peddle. I am using a 2% Thoriated 3/32 electrode with a freshly ground tip and a 3/8 cup orifice.

Once I have established the arc and begin moving forward, with or without a filler rod, the arc will suddenly flare-up very brightly for a second or two and then go back to the original arc shape. The flare-up is so bright that I have to stop and let my eyes adjust before I can continue. This happens intermittently every 5-10 seconds.

I never had this problem on the high-end Miller equipment I learned on at the local Tech College. I have welded with this machine with no issues in the past but this is my first attempt at welding 3/16 to 16gauge.

I am well aware most issues are "user error" but I can't figure out what is causing these flare-ups.

Any suggestions are greatly appreciated.

Frustrated in Cincinnati