porosity problem

[Andy]

Hello,

I have a PP256 that I'm having porosity problems with. I'm welding 1/2" plate to 1/4" 3x3 angle iron. One weld will go fine, then the next is a mess. I ground down to bare metal and cleaned with acetone. The tungsten is sharp and clean. I'm using a #7 cup with a gas lens. The argon is set to 10L/min. I'm maxing out at about 250 amps with the peddle. The ground is attached to clean bare metal on the angle iron. Any idea what I might be doing wrong?



Thanks,

Andy