Tig Weld Porous and Gray (Mild Steel)

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I'm basically brand new to TIG, less than an hour under the hood. I picked up a lower end Inverter tig welder (Primeweld TIG 200D) and have been trying to lay down a consistent 1G plate weld. I am running 1/16th inch tungsten at 20 CFH (100% Argon ofc) and using some er70s-2 mild steel filler rods. I have seen a of porosity in my welds, worm holes on the outside in consistent fashion, and always a gray sort color, sort of like the color you would see in a nasty cast aluminum break. I always clean the mill and rust/grease off with a grinding wheel, and use a towel to wipe it down. I can hear adequate gas coverage and run probably between 95-150 amps on 3/16 in mild steel. I am running a #6 cup. Any ideas?Century FC-90Primeweld TIG 200D
Reply:It had been noted that grinders will smear grease and oil.  Try acetone.
Reply:Are you dipping your tungsten? That is a sure way to cause porosity. +1 on cleaning with a solvent (acetone, denatured alcohol, etc.) after removing the mill scale. Bad or mislabeled gas will do that too.Miller Multimatic 255
Reply:wipe the grease off with acetone or alcohol first, clean mill scale off and re wipe.  get a 3/32 tungsten.  Just try running beads for a bit to learn the machine.  Get a puddle asap and motor, pushing the puddle.  IF the puddle isn't forming quickly, turn the amps up.  stay close to the work and tilt the torch just so you can see the tip (about 5-10 degrees from perpendicular).  maybe turn the gas down a bit, a 6 cup will want 12-15 cfh.
Reply:No, I'm past dipping the tungsten. Will try acetone, I believe the gas is clean, probably user error. Any other tips? Torch angle is probably 75-80 degrees. I understand the amperage is recommended to be a 1 amp per thousandth of material, I am using a foot pedal and just press until I see the molten puddle and then start to dab the filler. Sometimes I hear what I can only describe as a soft clicking sound when dipping the filler wire, typically when I am not pushing the pedal enough, can anyone explain that? My welds are definitely better when this clicking doesn't occur.Century FC-90Primeweld TIG 200D
Reply:

Originally Posted by GoK4rtFanatic

I'm basically brand new to TIG, less than an hour under the hood. I picked up a lower end Inverter tig welder (Primeweld TIG 200D) and have been trying to lay down a consistent 1G plate weld. I am running 1/16th inch tungsten at 20 CFH (100% Argon ofc) and using some er70s-2 mild steel filler rods. I have seen a of porosity in my welds, worm holes on the outside in consistent fashion, and always a gray sort color, sort of like the color you would see in a nasty cast aluminum break. I always clean the mill and rust/grease off with a grinding wheel, and use a towel to wipe it down. I can hear adequate gas coverage and run probably between 95-150 amps on 3/16 in mild steel. I am running a #6 cup. Any ideas?
Reply:Also, the tungsten stick-out past the cup is important IMO.  Too long of a stickout coupled together with being 25° off the vertical = compromised gas coverage.

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