Given the current obsession with tungsten prep...

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I thought i'd try and show that it's as much personal preference as anythingOne fresh pack of 1/16" tungstens. One's been sharpened for DC (in the collet assembly)The other was put UNPREPPED into the torch and used to weld this coupon- 0.065" Al, 3/32 filler,...Worked fine, nice stable arc though it may be a slightly different story for a fillet weld- maybe at the end of play tomorrowClose up of the tungsten afterwoodsWhile tungsten prep influences arc shape (and penetration to a small extent) there is no right and wrong way
Reply:Hotrodder,I agree that to a large extent it's personal preference, but with no disrespect, to a LARGE extent it determines depth of penetration, because of the influence on the arc shape.  The sharper the grind, the more the arc fans out, and the less heat is concentrated in one area.  The penetration between a 30 degree vertex angle (similar to the one you have mounted in your first picture) will be about 1/2 of that with a 60 degree vertex angle (much blunter), and as much as 60 percent less than the flat tungsten, given the same aperage, standoff, and travel speed.I know it sounds counter-intuitive, check out AWS welding handbook Volume 2, "Welding Processes", Eighth Edition, page 82 for an excellent representation of the effect of tip angle on penetration.Best regards, KbnitI r 2 a perfessional
Reply:Oh, and by the way, those are some damn nice welds.I r 2 a perfessional
Reply:Originally Posted by kbnitHotrodder,I agree that to a large extent it's personal preference, but with no disrespect, to a LARGE extent it determines depth of penetration,...
Reply:Hotrodder:Thanks for helping to quell the obsession. There is quite a fervor about the 'exact everything' of TIG.Which filler 4043, 5356?FWIW: I'm in TIG class and tonight I learned walking the cup and passed vertical up. 9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Originally Posted by Craig in DenverHotrodder:Thanks for helping to quell the obsession. There is quite a fervor about the 'exact everything' of TIG.
Reply:Originally Posted by hotrodderFar too much IMO. Arc length is the only real biggy with regards to 'exactness' that comes to mind at the moment
Reply:Hey, wait a minute.This is Aluminum.  The very same aluminum that its often suggested using a balled tip.I know the tip angle can affect the heat profile, and agree that in a manual process these slight variations just get compensated for.  If you want real control of the heat profile, frequency control is a much stronger effect.
Reply:Originally Posted by rlitmanHey, wait a minute.This is Aluminum.  The very same aluminum that its often suggested using a balled tip.I know the tip angle can affect the heat profile, and agree that in a manual process these slight variations just get compensated for.  If you want real control of the heat profile, frequency control is a much stronger effect.
Reply:Originally Posted by rlitmanHey, wait a minute.This is Aluminum.  The very same aluminum that its often suggested using a balled tip.I know the tip angle can affect the heat profile, and agree that in a manual process these slight variations just get compensated for.  If you want real control of the heat profile, frequency control is a much stronger effect.
Reply:Hotrodder,Yeah, you're right on the aluminum, I think that it's the mother of all wives tales when it comes to welding.  Depending on the application, I weld it AC or DCSP, mostly DCSP when I have to get the mother to pass penetrant inspection, cuz the AC cleaning catches too much penetrant.  But there are a dozen ways to skin that cat, just depends on the application.  I get guys coming in to apply for a welding job, when I ask them if they've ever DC'd aluminum, all I get is a blank stare.....I r 2 a perfessional
Reply:Originally Posted by hotrodderYeah, i picked Al as every time a thread comes up about tungstens/tungsten prep it's always the same... you want a sharp tungsten, No it HAS to be pure, balled with DCEP etc, etc.All i was trying to illustrate is that is doesn't really matter anywhere near as much as many people think.
Reply:Originally Posted by kbnitHotrodder,I agree that to a large extent it's personal preference, but with no disrespect, to a LARGE extent it determines depth of penetration, because of the influence on the arc shape.  The sharper the grind, the more the arc fans out, and the less heat is concentrated in one area.  The penetration between a 30 degree vertex angle (similar to the one you have mounted in your first picture) will be about 1/2 of that with a 60 degree vertex angle (much blunter), and as much as 60 percent less than the flat tungsten, given the same aperage, standoff, and travel speed.I know it sounds counter-intuitive, check out AWS welding handbook Volume 2, "Welding Processes", Eighth Edition, page 82 for an excellent representation of the effect of tip angle on penetration.Best regards, Kbnit
Reply:Originally Posted by kbnit, when I ask them if they've ever DC'd aluminum, all I get is a blank stare.....
Reply:Hotrodder,  While the blunt tungsten did work for you, it is evident it should be avoided due to excessive bead width. Although it is hard to determine in a 2d photo, that bead appears 4 to 5 times base metal thickness. Thanks for the experience, but all in all, it's not the way to go.
Reply:I wasn't suggesting this is the way to go- simply illustrating that tungsten prep doesn't influence weld quality to the extent that many believe. If you read KBnit's and Rojo's posts and the link i posted it's clear that 'blunter' is generally more suited for thicker material (one of the reasons why i used thinish aluminium AND 3/32 filler- again not ideal for the thickness) and the arc is narrowerIt's a full pen weld, if i'd come off the pedal faster as i approached the edge of the coupon (around 3 x 4") it would've have similar cross section profile on both sides. Bead is 5mm wide give or take 0.5mm FWIW
Reply:Sorry I am an old turd and still use pure balled AC on Al. Fanatical grinding to the perfect angle is unobtainable. Grind it and go. Your skill makes more of a difference. And by the way there is no such thing as a perfect weld. Just ones that pass good enough.. Do what works for you.
Reply:Originally Posted by hotrodderDoesn't suprise me but then a blank stare is becoming a more common response to many things  but it's almost a standard response to welding Al with oxy fuel (and/or stick) tooRojo,Largish pieces of 5/16" with a v205t! I don't envy you, that must be slow (and extremely HOT) going indeedProbably too late now but what about a helium/argon mix to speed things up some? KB would probably use DCEN (assuming the relevant bits of the boat can be got clean enough) too but either way it'll be like a having a bunch more amps to play with
Reply:Red,Yes, you can DCSP (sorry, DCEN) aluminum.  The key, as hotrodder pointed out, is making sure that you can get the pieces clean enough.  With AC, the reversal of polarity is what pushes the oxide to the edge of the puddle, giving you clean metal during the EN phase.  No such help with DCEN.  You're gonna want a powered wire brush at a minimum to remove the oxide from the weld area and the faying edges.  You mentioned you've tried it and got nowhere fast.  All I can tell you is how I do it.  Full pedal to get a puddle, you need a lot of heat to get the initial melt, then pedal back, then you start the filler in, and start moving fast, because the puddle will want to spread as the heat starts to spread out into the base metal.It helps to be running 75He/25Ar with a xfmr machine, but most of the inverters coming out now tell you to run straight Ar.  Just my .02Best regards, KbnitI r 2 a perfessional
Reply:Originally Posted by kbnitRed,Yes, you can DCSP (sorry, DCEN) aluminum.  The key, as hotrodder pointed out, is making sure that you can get the pieces clean enough.  With AC, the reversal of polarity is what pushes the oxide to the edge of the puddle, giving you clean metal during the EN phase.  No such help with DCEN.  You're gonna want a powered wire brush at a minimum to remove the oxide from the weld area and the faying edges.  You mentioned you've tried it and got nowhere fast.  All I can tell you is how I do it.  Full pedal to get a puddle, you need a lot of heat to get the initial melt, then pedal back, then you start the filler in, and start moving fast, because the puddle will want to spread as the heat starts to spread out into the base metal.It helps to be running 75He/25Ar with a xfmr machine, but most of the inverters coming out now tell you to run straight Ar.  Just my .02Best regards, Kbnit
Reply:Red,Flap discs should do it. PM me if you have problems, I'll do my best to talk you through it.Best regards, KbnitI r 2 a perfessional
Reply:A thoroughly interesting thread to follow. I don't work with ali (but I'd like to one day) but I feel it's been very educational and explained rationally.I hope I don't screw it up for you guys, but I'd expected acetone to have been mentioned by now..."One of the things we have to be thankful for is that we don't get as much government as we pay for." (Charles Kettering)Mitch 180 (NZ)Lincoln SAM-400-220 + ?-400 Fordson Major + 2 x Tractapac Humber 80 + Procut 40 PlasmaMiller Spectrum 375
Reply:Originally Posted by TractapacA thoroughly interesting thread to follow. I don't work with ali (but I'd like to one day) but I feel it's been very educational and explained rationally.I hope I don't screw it up for you guys, but I'd expected acetone to have been mentioned by now...
Reply:There's always one!! . Solvents have their place along with the other various pre welding tasks, depends what your making. Although i went thorughly OCD with a little Ti job i did recently i'm still not convinced it's absolutly necessary for some applications. I did a little test with the small offcuts i had left, a bit mickey mouse so i haven't bother starting a thread for some feedback. The coupon i knocked out here wasn't prepped at all, no wire brush/scotchbrite anything, just peeled the plastic off after cutting it in half and welded the bits back together. Rojo, KB is the better choice for some DC (EN / SP) tips but in my experience you never get a well defined puddle, it always looks dirty
Reply:i was practicing yesterday(= change tungsten every 74 seconds)..found  that between the tungsten being hot, and getting stuck in the collet, it was hard and slow just getting the old tung out ofthe torch..solution-stick the filler to it so bad you use the filler as a handle...Originally Posted by RojodiabloAcetone is the one factor to aluminum welding that I have found to be LEAST necessary. I only use it where I have dunked my tungsten ( about damn near everywhere!!!!) and if I get any tapes, glues, oils on the material. Other than that, after having burned up a ton of aluminum, acetone is almost a waste of time vs. good old wire brushing and a shot of  air  to blow off the oxide dust.
Reply:I bend the collet so when I turn the cap, then tungsten falls out in a dish.  I use a lot of em too. I don't find much difference in the shape of the point.  I prefer gold, but they all work.Oh yeah, about the acetone.  I don't use it hardly at all.  No flamables.  BUT take a white paper towel , soak it with acetone and wipe down a filler rod.  You will see for your self.DavidLast edited by David R; 08-29-2008 at 07:35 PM.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David ROh yeah, about the acetone.  I don't use it hardly at all.  No flamables.  BUT take a white paper towel , soak it with acetone and wipe down a filler rod.  You will see for your self.David
Reply:Originally Posted by Mud SpazYou can do the exact same thing with denatured alcohol and have the same results without the potential health, and safety, hazards.
Reply:x2 !  Great tip. Having Acetone in the garage near the welder was making me a bit nervous. I also found it ridiculously expensive.And you ever run out of rubbing alcohol when you're trying to finish a time-critical job, you could always reach for some Smirnoff as painful as it might be
Reply:Originally Posted by turboguyx2 !  Great tip. Having Acetone in the garage near the welder was making me a bit nervous. I also found it ridiculously expensive.And you ever run out of rubbing alcohol when you're trying to finish a time-critical job, you could always reach for some Smirnoff as painful as it might be
Reply:david rfoto of the bent collet?i think the one thats giving me trouble, 3/32, is  a little deformed..i used  some 1/16 today and  it  was easy to get them out  . thx..
Reply:Just pry the halves apart a little so they spring open.  Don't over tighten the black cap.If they didn't drop out, it would take me a lot longer to weld things because I dip frequently.  DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by rlitmanHey, wait a minute.This is Aluminum.  The very same aluminum that its often suggested using a balled tip.I know the tip angle can affect the heat profile, and agree that in a manual process these slight variations just get compensated for.  If you want real control of the heat profile, frequency control is a much stronger effect.
Reply:ii have been sketching a torch i want to patent..it has a magazine with ten tungstens ..a  push of a button  and the old tungsten is ejected as a new one  is fed in..
Reply:I know there are some strong feelings about the use of solvents used to clean weldments prior to welding, and I'll just offer the following as experience from nearly 20 years of working manufacturing semiconductor capital equipment.  These are the machines that turn a silicon wafer into a computer chip.  We have a class 100 cleanroom, equivalent to a surgical operating theater in terms of cleanliness, except without the germs.  The patterns on semiconductors are so small, that any amount of residual chemistry left on the parts that could volatilize and contaminate the wafer must be minimized.In terms of what will leave the least amount of residual chemistry on the part, as we have determined through years and years of mass spectrometry, and mind you this is only in critical applications, from worst to best - 1.  Methanol (Wood alcohol) - might as well wipe it down with oil.  Contains formaldehyde.  Considered highly toxic, can cause blindness and death.  Flammable2.  Denatured Alcohol - Ethanol that has had methanol, Isopropanol, methyl ethly ketone, or even acetone, or other additives added to it.  It is highly toxic by the nature of the addition of these chemicals.  Flammable3.  Ethanol - good cleanliness, high volatility, not toxic, except in extremely high doses, as ethanol is the alcohol in the alcoholic beverages you consume.  Flammable4.  Isopropanol - (Some times called Rubbing Alcohol)  Dissolves a wide range of contaminants, low toxicity.  Flammable5.  Acetone - Excellent cleanliness, very high volatility, very low residual.  Is considered toxic only in high doses.  It's what your wife uses to clean the fingernail polish off her hands.  Flammable6.  Isopropanol, Semiconductor Grade - Best cleanliness, lowest residual chemistry, low toxicity, very, very expensive.  Flammable I'm not advocating the use of any particular solvent, I think that, as professionals, we should base our choice on what desired result we want (grind and blow the CR, but you'd better sovlent clean that stainless), and for those non-professionals here, you have access to the internet, look up the chemistry, and take into account the safety precautions that are noted for each, and you can always come here and ask the pros if you need additional help.Just my .02 worthBest regards, KevinI r 2 a perfessional
Reply:Originally Posted by kbnit4.  Isopropanol - (Some times called Rubbing Alcohol)  Dissolves a wide range of contaminants, low toxicity.  Flammable