Tig Porosity problem

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My specific question is: how much cruddy build up inside the nozzle / cup is normal or acceptable? I'm practicing mainly with 1/16" 2% Thoriated with #5 nozzle. I don't yet have another new clean nozzle to try. Any time I dip the tungsten I switch to a fresh one, ground on a 2-wheel bench grinder wheel that is not new, but I never really used that side for anything else, and have only used it since for tungstens.Backstory:I have a scratch start rig with a Lincoln Tombstone AC/DC and an air cooled wp17v torch setup. Practice / work pieces include 3/16" mild steel coupons from earlier Votec welding classes, and 1/8" angle from scavenged bed frames.I am a new Tig welder hobbyist, and have some stick experience. I havent used the Tig setup in a couple of months, and it worked fine: i sometimes got porosity on dirty spots on otherwise cleanly ground coupons, usually from the bead previously run.I'm getting porosity a lot, but not always, on joints and on beads run on the plate. So, I don't think I'm picking up contamination from the bench or backside of the piece. I have read some threads and will be checking the hose and torch, etc. for air leaks. My bottle is down to about 20lbs I think, I have another full one I'll try.My filler is 70s2 or 70s6 1/16". Stored in an open topped PVC tube on the cart.Lincoln AC/DC 225/125 and WP17. 75A AC is for pipe thawing!HH 140 - new addtion 9/2012.I didn't agree, but hoped for Hope and Change.I got change for myself and my family: for the worse.This is the reality of: Barackalypse Now. Again.
Reply:Originally Posted by jtcnjMy specific question is: how much cruddy build up inside the nozzle / cup is normal or acceptable?
Reply:Many times if you are getting dirty welds on clean metal just simply the gas coverage around the weld isn't good enough. Many people like to use very small cups and I can never figure out why besides when needed in tight spots. I use a strait cup (unsure of the actual size), I say strait as in the cup doesn't neck down off the torch. Even still I find times my puddle will move out of gas coverage at times and get dirty. I am actually looking into getting bigger cups for more coverage.Pic of my wp17 with strait cup. The cup is white because of some anodized nuts and bolts I was welding earlier.
Reply:Have u tried using gas lens and cup instead of standard?Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:No build up is acceptable. Basically that is contamination that will find it's way into your weld.Lincoln SA200's... at least 15 - 20. They come and go. Growing partial to the "Short Hoods" in my old age. Last count on Short Hoods was 13 in possession.
Reply:Thanks for the replies. I filed out the nozzle, checked my hose and torch fittings, my tank has at least 60lbs, and realized I had the bottom of the regulator ball above 15 cfm so I was over 20 at the top of the ball. Maybe it was too high.It is working well now. I know the tungsten point grind length should be 2 or so times diameter, and to blunt it slightly, but I read somewhere to leave the point on the small .040 and 1/16" I am mostly using.Also, am I doomed to not making good welds with a scratch start set-up? Is it normal for the tungsten to blacken up inside the collet area?What say you?Lincoln AC/DC 225/125 and WP17. 75A AC is for pipe thawing!HH 140 - new addtion 9/2012.I didn't agree, but hoped for Hope and Change.I got change for myself and my family: for the worse.This is the reality of: Barackalypse Now. Again.