How long to use a TIG electrode?

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I've been using my TIG needle for quite some time, is'a WL15 98,5% W + 1,5% La, gold. I weld steel and aluminum with it, probably 50/50 share. During the repair of a broken motorcycle mount I had extreme problems welding the aluminum. A lot of pores were popping up and I had to re-grind the hole thing several times, the weld locks like sh....Then I changed the electrode, and then welding was fine (as fine as this dirty/oil cast allows)Could it be, that the "old" electrode contaminated my wed? Should I keep electrodes for steel and aluminium separated? BTW: I used 230A (with pedal) and argon.Thanks MaikiLast edited by Maiki; 03-04-2015 at 05:30 PM.
Reply:A TIG electrode will last a very long time. I'm speaking of types other than pure tungsten. They will degrade on the tip if inadvertently stuck into the weld. Then they can simply be resharpened, but you knew that. LOL. I can see that your problem is dirt, grease and grime on the aluminum motorcycle crankcase. I've welded many Harley-Davidson cylinder heads, crankcases, transmissions and primary cover parts. They can be extremely difficult to get clean enough to weld. Even after careful cleaning and preparation, oil will boil out of the porous aluminum when heated to make a weld. The early Harley items were generally sand cast and they are the most difficult to weld. The newer cases, since the late 1990's are somewhat easier since many of them are die cast and seem to be less porous. I can also see that there is a great deal of aluminum oxidation on that part. As you probably know, the oxides are very heat resistant and can be difficult to remove from the heated area. I suspect that your first electrode was simply coated with oxide particles and oil from the base metal. Likely a good scouring of the tip should renew it since the oil and other effluvia won't penetrate it. By the way, your welds do not look bad at all considering the amount of accumulated dirt and oxides in that aluminum. I have a large powder coating oven and I will use that for a period of time at 350 degrees F. to provide for out-gassing and later for preheat for my weld. Keep smiling!Last edited by gnm109; 03-04-2015 at 11:07 PM.Miller Millermatic 252Miller Syncrowave 200Liincoln AC-DC 225Victor O-A Set
Reply:Thanks for your answer. Yes, the motor was/is extremly dirty. I wire brushed the welding area and grinded the joining surfaces. Then I used aceton, but I guess, that's not enough. I also re-sharpened the electrode a lot, till I needed to change to a new one...The engine is a 1990 Honda ST1100 (Pan European). It was sitting in a barn the last 8 years after a crash with fire. Got it cheap and I want to put it in a buggy...
Reply:I use them till they are too short to reach from the collet to the work...but I am the quintessential cheapskate.I have only ever used scratch-start rigs, and when that is the case, one becomes a very accomplished tungsten sharpener, or pretty good at getting a clean start.Last edited by geezerbill; 03-05-2015 at 09:23 AM.Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:Sometimes it's a good idea to cut it a little rather than resharpen. In your case I would have done that.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:[SIZE=3]I have probably every Tungsten known to man and use a Miller Dynasty 350.  After using a ton of different tungsten'sI still like the Red Thoriated  for most AC work.....2% Lanthinated (Blue)  works good for High Amps AC  but for small stuff I use the RED Tungsten shapes are different with  inverters so keeping the tungsten fresh is critical to consistent welds.  I freshen up my tungsten probably every 30 minutes of constant welding and find it makes things much nicer.  I have welded all day before without a DIP  and still freshen up as the tungsten corrodes.Last edited by B_C; 03-05-2015 at 03:54 PM.  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock