this little flat on the end of the tungsten

[Mike Mcdermid]

What does it do never tried it, never taught to grind a flat on ,was always taught tungstens are pointy

[Amaro Bikes]

Hi Mike

Well, ther're loads of tech text out there, sure you've read them, all about arc stability, so I'll just go to my personal experiences inc ase are of interest:
- If completely pointy and sharp as a needle, there're quite more chances of getting the welding pot connected with the tugnsten, kind of making a "bridge" betwwen them, and also the place where you're "pointing" at with your arc will be too narrow and more difficult to "control". With a "flat" tugnsten you'll have a much more predictable arc, and also kind of stable. When having this small flat end the arc can ditribute much better the heat in both metal pieces to weld, without going too much in a very "narrow" influence area. Also the arc then seems to have more issues to "find its place" when you start it.

So, it's about a properly grinded (longitudinally) tugnsten as if you're going to leave it purely pointy, but then make a very small flat end or even kind of "ball" shape, so to avoid the problem with "too sharpen knife that can cut without even touching". Not really a flat tugnsten, but neither a needle one.

Also, this just speaking on DC welding, can't speak for AC/DC and alluminium wich might be different?

[edoz]

You get a little better stability with a small flat on your tungsten, it's the same reason that spark plugs have flat electrodes. Also at higher currents the tip can deteriorate and little chunks can break off and end up in the weld pool. Anything thicker than about .030" and I put a flat on.

[Jonathan]

My machine running about 60 pps seems to like a sharp point with a longish taper on bike tubes. Welding shop fixtures, tables and stuff with more amps I am not as picky which results in flatter tips.

[zank]

I blunt the tip a bit when I'm running AC. A 2% lanthanated electrode then forms a little ball on the tip. Not nearly as big of a ball as a pure tungsten electrode. The small ball on the 2% lanthanated still gives me good arc stability when getting into corners.

When I'm running DC, I sharpen to a point and then just barely knock off the little whisker on the tip. I like a shorter point. It offers a narrower arc cone and deeper penetration than a long taper. Just works a bit better for me.

[Rosko]

Usually I like to let folks find their own way to the info but this one can be hard to find even with a little due diligence. Certainly required reading if you are a TIG devotee:

http://www.diamondground.com/TungstenGuidebook2011.pdf

[Mike Mcdermid]

thanks for the feedback folks

always used tungsten andgle to control the arc width and penetration ,this flat i assumed was to stop folks blowing the end off the tungsten when pushing a few too many amps through a small tungsten ,i had never seen it as an arc control till recently

Zank i always used pointed tungstens when using helium/argon and balled most of the rest of the time on aluminium

ill have a play with a little flat to see what direction that leads