Question on tig arc

admin

I am still new to tigging.  When I have my arc it doesnt seem as precise as I would think it would be, it seems to "flare out" like a reverse funnel i guess you could call it.  Should it be more of "pin point"?  Any ideas? It does this for mild or stainless.Thanks,Dave
Reply:Pay very close attention to the exact type and size of tungsten you choose, THEN pay even more attention to getting the correct point sharpened onto it. That's all I got. City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:The tungsten is red 3/32. 2% thoriated I believe.  Any advice on grinding the tip?  What grit,style wheel do you recommend?  It is just for recreation, dont have $600+ for a "real grinder" yet.Thanks
Reply:The tungsten should be ground so the lines from the grinder are parallel to the tungsten.  Point the tungsten at the wheel and use the face of the wheel.  If the lines from grinding are around in circles, the arc gets all confused.  Something about electrons......The sharpened part should be 2 diameters long, sort of like a pencil.  The sharper the tungsten, the more focused the arc.Diamondground has a website that explains it better than I can.DavidDavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Take a look in the miller handbook under "electrode preparation" section starting on page 35.  They have some nice pictures of what happens with different electrode angles and discuss sharpening techniques.http://www.millerwelds.com/education...Book_Chpt4.pdfTim
Reply:You're correct, the arc is generally a cone shape.  It is difficult to get a good measurement on the dimensions of the TIG arc, but many researchers have tried and the data generally shows that the arc power comes off the tungsten in a gaussian shape, like a bell curve, also called a "normal distribution".So anyway, as the arc length (tungsten to work distance) is increased, the arc diameter grows rapidly, so for the most concentrated arc, you have to hold a tighter arc.With a longer, and hence broader arc, the efficiency of arc drops rapidy, because the wide fringe edges of the arc don't have enough power concentration to help with melting, much of the power is just lost to the surroundings.A mix of 95% Argon / 5% Hydrogen is often used for very precise, thin gauge, autogeneous (no filler) welds on stainless steel and nickel alloys, because it tends to produce a more concentrated arc.Newer power supplies have adjustable AC frequency for aluminum welding, and higher frequency settings tend to produce a more consticted arc.And as mentioned, the grind angle and surface finish on the electrode will have an effect on arc shape.  Try a sharp point versus a blunt point, and ja coarse grind versus a polished grind, then let us know if you see a difference.
Reply:Chuck the tungsten in a cordless drill and let that spin it against the gringer wheel. It will be SHARP and you won't have to worry about burning your fingers.That is just ONE tip I leaned from ZAP's little clinic this past weekend!
Reply:If the arc is flaring the tungsten could have a break in it.Disclaimer; "I am just an a$$hole welder, don't take it personally ."