GTAW Post Purge

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Is there a general "rule" for how long of post purge to set?My Dynasty is currently set for 15 seconds of post flow, and I just cannot believe that the tungsten needs THAT much cooling.  Much obligedThermalArc 185MillerMatic 180 w/ AutosetVictor Cutskill Oxy/AcetyleneThermal Dynamics Cutmaster 38and spite!
Reply:Originally Posted by zapsterI just keep mine at 5 seconds all the time.....zap!
Reply:Anything over 5 or 6 seconds is just a waste of gas.. And we all know what gas costs now don't we..Kinda makes you wonder if the manufacturers are in bed with the gas suppliers.. ...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:5 seconds for anything/everything (Aluminum, Steel, Stainless Steel, etc)?ThermalArc 185MillerMatic 180 w/ AutosetVictor Cutskill Oxy/AcetyleneThermal Dynamics Cutmaster 38and spite!
Reply:Originally Posted by DirtyLittleSecret5 seconds for anything/everything (Aluminum, Steel, Stainless Steel, etc)?
Reply:You have to keep the tungsten shielded while its hot.  So post purge while also keeping the end of the weld shielded, also shields the tungsten, keeping it nice and shiney.Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.
Reply:FINALLY something simple/straightforward with TIG, and save some $ on tank refills!Now the confusing part...changing my settings! Good to get this on the board for us youngin's.  Search function just rendered a bunch of miscellaneous.ThermalArc 185MillerMatic 180 w/ AutosetVictor Cutskill Oxy/AcetyleneThermal Dynamics Cutmaster 38and spite!
Reply:My vintage 250/250 TIG/Stick Idealrc Lincoln has a post-purge control. That is, you set a knob on the control panel to match the size of tungsten that you are using. 1/16" gets about 4 seconds, 3/32" gets a little more, say 5 or 6 and so on up to 1/4" which might be as long as 20 seconds, although I never use more than 1/8" tungsten. .As Zap says, if you're really concerned, just tap the pedal once more and double your time. Otherwise, 4 or 5 seconds should be sufficient.Miller Millermatic 252Miller Syncrowave 200Liincoln AC-DC 225Victor O-A Set
Reply:Most of the books say something like "1 sec per 10 amps", the idea being that at higher current, the tungsten will be hotter, and the stop of the weld will also hold more heat. This is the cover all bases rule, so shorter should usually be OK.I just go with about 5 to 10 seconds (the knob isnt marked clearly on the machine I use at work), shooting for 5. I turn it up at higher current if the need shows, like the tungsten coloring or the stop on the weld showing a problem. My Maxstar has the 1 sec per 10A rule programmed in, and I have NEVER had a problem there.Some materials will need more time (some stainlesses, some exotics) to avoid contamination at the weld stop.
Reply:Set it to a conservative 5.5 seconds.  Fortunately, it took about as long to program my box as well.Thanks!ThermalArc 185MillerMatic 180 w/ AutosetVictor Cutskill Oxy/AcetyleneThermal Dynamics Cutmaster 38and spite!
Reply:Some machines have a pre purge dial also..Lets the gas start before the arc..My Hobart don't have that..So just tap the pedal before you hit it for real..I like to start a weld with the gas already flowing...Rather that everything happening at once.....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 zapsterSome machines have a pre purge dial also..Lets the gas start before the arc..My Hobart don't have that..So just tap the pedal before you hit it for real..I like to start a weld with the gas already flowing...Rather that everything happening at once.....zap!
Reply:So, you guys are pre purging about 5 seconds as well?  I thought pre purging was for aluminum/S Steel.  What's the function of pre purge anyhow?ThermalArc 185MillerMatic 180 w/ AutosetVictor Cutskill Oxy/AcetyleneThermal Dynamics Cutmaster 38and spite!
Reply:Originally Posted by DirtyLittleSecretSo, you guys are pre purging about 5 seconds as well?  I thought pre purging was for aluminum/S Steel.  What's the function of pre purge anyhow?
Reply:Ah, didnt even think about that.  Gues it would take a second for the gas to initially reach the cup wouldnt it!?Gee, this might just help my welds.ThermalArc 185MillerMatic 180 w/ AutosetVictor Cutskill Oxy/AcetyleneThermal Dynamics Cutmaster 38and spite!
Reply:Originally Posted by DirtyLittleSecretAh, didnt even think about that.  Gues it would take a second for the gas to initially reach the cup wouldnt it!?Gee, this might just help my welds.
Reply:5 seconds here too, but occasionally I will bump that up.  When welding out of position pipe with a lift arc and no pedal access, I have to whip the tungsten away to extinguish the arc, then move the torch back to the weldment before the shielding gas pulls away.  I'll set it a few seconds longer in this case to give me some workroom.
Reply:Why pull some post purge time setting out of the air, just look at the tungsten and the weld.If the tungsten turns blue after a weld, you could increase the post purge time to extent the life of that tungsten at that current level.If you need to prevent discoloration of the weld, like in titanium welding, you may need to adjust the post purge to protect the end of the weld.