Tig post flow with aluminum?

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Was watching BC's latest video and noticed very little pause time at the end of the aluminum weld for post flow coverage. when I went to tig school and on the internet post flow was always said to be important for steel and filler to avoid contamination till they cool. Is this not true of aluminum? I am not saying BC is doing it wrong he cranks out picture perfect stuff and after 3 years I am still learning. Just don't know. As far as cooling I mean molten fluid state of puddle. I know you don't need post flow till the weld is ambient temp.Last edited by tig dummy; 11-16-2013 at 10:35 PM.
Reply:Aluminum oxidizes, but not like steel in that it does not form "rust", as in iron-oxide.  Aluminum oxide is for the most part transparent until the oxide layer really builds up over time and turns whiteish.  That aside, BC has a Dynasty 350 machine which can control a million things including the temperature of the sun, weather patterns, etc, and I'll bet he has tweaked his settings to get perfect welds in every sense, including minimizing the heat input into the metal, which in turns influences how much post flow is needed.  There's many tricks of the trade that are just not apparent until you start experimenting with your own equipment 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:Post-flow is important for preserving the tungsten as much as anything else.  If you are welding aluminum, this is especially true as the tungsten and torch are receiving more heat than during DC welding operations.  Reducing post flow too much will reduce the useful life of the tungsten you are using.  This does not mean that you need to hover over your weld puddle though - just maintain enough post flow time on your welding power supply to be shielding the tungsten as it cools (I use 5-10 seconds depending on amperage with 3/32 tungsten).  Post flow protection of the weld puddle is not really necessary, and in some cases makes pulling off the bead and eliminating the crater more difficult, depending on technique.Miller Dynasty 200 DXMiller CP-300 with 30A feederHypertherm Powermax 900Oxy-fuel w/Harris torchesScotchman Glide-in bandsawMonarch 10EE latheEmi-Mec Autoturn latheDeckel FP2NC milling machinePro-Tools 105 Bender
Reply:3 seconds post flow..No more..No less.Material you are welding is immaterial....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapster3 seconds post flow..No more..No less.Material you are welding is immaterial....zap!
Reply:Originally Posted by zapster3 seconds post flow..No more..No less.Material you are welding is immaterial....zap!
Reply:Originally Posted by jontheturboguyIm going against ya on this one.  For my air cooled setup - when welding aluminum - I set the post flow long enough so that the tungsten has enough time to cool past the point of oxidation from atmosphere contamination.Really sucks to light up on the next pass only to watch your tungsten deposit its former self into the bead.....
Reply:Originally Posted by zapster3 seconds post flow..No more..No less.Material you are welding is immaterial....zap!
Reply:The post flow on my Syncrowave 200 seemed a bit long to me. It defaults to 5 seconds up to 50 amps. For every 10 amps above that, it adds a second. Thus, if you weld at 100 amps. you would have 10 seconds. 150 amps would be 15 seconds 200 amps would be 20 seconds. I modified it to 5 seconds since I noticed that I was using a lot of argon on post flow. I seldom weld large items so I'm usually closer to 120 amps.  It seems to work well enough at that setting.Miller Millermatic 252Miller Syncrowave 200Liincoln AC-DC 225Victor O-A Set
Reply:Originally Posted by zapsterMaterial you are welding is immaterial.
Reply:Originally Posted by duaneb55Isn't immaterial material just empty space?