Tig Welding Alminum- FAIL- need some help

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I'm a bit embarrassed to post this but... I need some experienced help with aluminum TIG welding.  Sorry this is long.Background:3 years ago, I bought a brand new inverter AC/DC TIG, (AHP - Alphatig 201) to learn on and do some thin aluminum welding.  I did weld what I needed to back then but, NONE of my welds were "presentable".  They were gas tight (intercooler piping) but the word "snot" comes to mind.  Given the little self respect I have left, please don't ask for pictures of my old welds.I resolved to devote the time to get better.  I've even looked into local TIG welding courses but since COVID- there's nothing.  I've been a serious hobby welder for over 30 years and I'm "reasonably proficient, as hobbiests go".   I can weld MIG, ARC and Oxy/Acet. I'm an engineer by trade, and I try not to do anything half way... but- this TIG thing has me really dejected and feeling down about my abilities.  I've quite literally spent DAYS reading and watching videos, each of which gives rise to a new sense of "hope" until.... I sit down at the TIG, where all my hope goes to DIE... the WTF death!!!I've gone back to basics and it seems things are getting worse!  Right now- my only goal is start a weld puddle of clean, shiny aluminum... and I can not!The coupon- 6061 T6 Aluminum - 1/4" thick. Washed with soap/scotch brite pad. Dried. Then wiped with Acetone (clean rag). Then wire bushed (by hand)- stainless brush  used only on aluminum, brushed in 1 direction only until bright and shiny. Air blown clean then immediately welded on to avoid oxide formation.  I also tried preheating- no difference. And I also tried a thinner .093" material- same prep- no difference.Machine- AHP ALphaTig 201XDGas- Running pure Argon  20 CFH( I've tried 2 different bottles with the same crappy results.  I've tried 10-40 CFH- no difference.  Both bottles seem to work fine on my MIG with spool gun on the same aluminum coupon)Tungsten- 3/32  2% Lanthanated (blue)- Ground 60 degree  leaving about .030 flat tip.  Specific grinding wheel only for  tungsten ( no contamination) & tip ground axially- not radially. I also tried purple tungsten- no change.Settings-  AC,  Torch lead -, ground lead + (attached directly to the weld coupon),  foot pedal control (2T),  Set to AC,  Main amps (tried 140-190) AC Freq ( tried 70-120), AC BAL (tried 30-60%), Post flow (tried 5s-15s).  NO PULSE FUNCTIONS USED... Straight AC welding.What happens is, a puddle forms BUT, it never gets shiny.  Soot develops around the weld and the pool itself looks dull and crackly, like it has a wrinkled oxide skin layer over the puddle.  It's as if I'm using the wrong shielding gas or over heating the aluminum. I've torn down the setup a dozen times.  I've checked for leaks, I've replaced collets, collet holders, caps, back caps, orings, teflon seals, about a dozen tungstens.  I've tried different cups, gas lenses... I've varied gas flow from 10-40CFH.  I CAN NOT establish a shiny weld pool!!! It's driving me crazy!!The welder seems to be working meaning when I vary AC frequency, I can hear the different pitches.  When I vary balance, I can see more heat on the tungsten at higher percentages and the tip balls up much more.  I don't want to add filler until I master getting a shiny clean weld puddle and even this eludes me.  What am I doing wrong?Last edited by jav; 11 Hours Ago at 04:21 PM.
Reply:Change to a 1/8th tungsten and set your amps MUCH higher. For quarter inch material, that machine needs to be wide open to get a puddle going properly. You really need a bit more power than 200 amps to get the puddle going correctly on quarter inch plate. Mash the pedal all the way at your max power settings to start the puddle, then feather off as needed/appropriate once you get the puddle going. Also do NOT try quarter inch plate on 120 volts. You need to be plugged into a 240 volt outlet.Miller Multimatic 255
Reply:Sounds like your prep is far above anything that I do so doubt that is the problem.  I’d try 120hz, 190 amps and an average cleaning setting (not familiar with your machine). A #6-7 cup should be plenty with 15-20 CFH.  Get your electrode close to the material and give it full pedal.  You should get a puddle within 1-2 seconds at most.  Once a puddle forms then move across your coupon.  If you are located near Ft. Worth you are welcome to come to my place and try my machine or bring yours and I’ll try to help you.Miller 350 DynastyMiller TrailblazerMiller 625 Plasma Lincoln Power MIGVictor oxy/acetyleneHyperthem 85
Reply:Thanks Louie-yes- I am running on 220v.  Per the chart  3/32 2% Lanth.  should be good to 180 Amps, No?    I agree on the amperage  for welding but my only goal right now is to establish a clean shiny weld pool- even a small one without full penetration.   I did  mention above that I also tried .093 aluminum coupon (80-100 amps) with no change to the weld pool appearance.  And- I  tried 190A on the 1/4" coupon but it didn't clean up the puddle...It did however, completely liquify a 3/4" corner of the coupon and it fell to the floor.  I don't think this is a current issue but I tried it and it didn't work?. BTW- even at 140A, I am getting full penetration to the backside of the 1/4" coupon.      I do understand the pedal feather back concept but I'm under the impression that you only feather the current back once you get the shiny puddle... and I'm not getting that and I don't know why?Thx BlucllrPlt-  I'd take you up on it but I'm in Massachusetts.... although I'm so frustrated I'd actually consider travelling a long distance to understand what I'm doing wrong.
Reply:Can you physically hear the gas coming out of the nozzle ? At 20cfh you should hear a puff followed by a hiss.What happens when you tig a piece of steel ? Do you still get soot ? Does the tungsten burn back to the cup.To get a good Idea of your gas coverage, take a piece of stainless steel, make a spot weld with no filler, flip up your helmet and watch the weld as the gas shuts off. It shouldn't change color much. If you move the torch right away after the weld, you can watch it make pretty colors. If it just looks grey and burnt then you have no gas coverage. Is you polarity correct, even in AC it still matters, you'll be on the wrong side of the balance.Good LuckAirco 250 ac/dc Heliwelder Square waveMiller Synchrowave 180 sdMiller Econo Twin HFLincoln 210 MPDayton 225 ac/dcVictor torchesSnap-On YA-212Lotos Cut60D
Reply:Update- Problem solved!And yes- I can hear and feel the Gas flowing out of the cup.  Yes I hear a puff followed by a hiss.  I did not (recently) try this on stainless as my main objective was improving my AC aluminum welding... but read belowIf you couldn't tell, I was REALLY REALLY troubled by this...  so today,I made up (6) 5052 aluminum coupons from a brand new sheet of 1/16" thick stock.  On the the way home from work, I stopped by a different supply house and bought another 100% argon tank.   I first cleaned the new stock as before, replaced all the torch consumables, new tungsten, and tried a weld at 65 amps- 120 hz, 30% balance - using 1 of the old gas cylinders.  Immediate crap.  Same as before. Went to 50 CFH on the gas- no improvement!   So I swapped in the NEW Argon cylinder AND just replaced the tungsten and OMG!!!! PERFECT!!!!   I can't beleive I've been beating myself up for days over what amounts to 2 bad cylinders of Argon!!!   I think my regular supply house filled the other 2 cylinders with 75 Argon/25 CO2 Mix???  The differnce is night and day!!!  I can't believe it!!!Now I can get back to practiceing but I've spent a lot of time and money and have no recourse for bad gas-both cylinders havine been purchased months ago.  I guess I'm changing supply houses.Last edited by jav; 9 Hours Ago at 06:33 PM.