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Importance of a pointed tungsten, TIG welding

I am new to TIG welding. And have difficulty maintaining a sharp tip on my tungstens. OK I can lay a nice bead and keep the tungsten clean if its two plates on a table. But in the real welding world its a bunch of pipes and structure that is in the way of getting a good angle on the torch and parts of varying thickness and poor quality fit ups that have to be welded while your hanging upside down inside a tight ships hull, and while activating a foot pedal by squeezing it between your two feet.

So on my last project I sharpened up 10 tungstens and started to weld thinking the ten tungstens would last the day (HA HA HA HA). After about the 4th tungsten in the first hour, changing tungstens was starting to get old. I started to realize that no matter how bad the tungstens got the quality of the weld always looked good. Now when I say looks good, up until now I've only done stick welding. The TIG machine makes me look like an artist compared to stick.

I was welding with tungstens that were so deformed they looked like they had a pair at the end of them. Then sometimes I would continue to weld and the pair would burn off and the end would actually appear somewhat sharp again. In any case the weld appeared the same no matter what the tip looked like.

So my question is, why should I ever sharpen a tungsten at all.

The project I was working on was a mild steal automotive subframe, using a Lincoln Squarewave 175 and ER70-S2 filler with Ceriated tungstens. OK I wasnt upside down in a ships hull.

John Roncallo

Reply to
Anonymous
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"jroncallo roncallo @snet.net>"

Reply to
Surfin'

I have tried Thoriated. In fact thats what I ordered but they sent me Ceriated and have a note that says its a direct replacement for Thoriated. It doesent matter the results are the same, a ball at the end of the tungsen the first time I touch the tungsten to the puddel.

My question is why should I care, the weld comes out nice anyway.

John Roncallo

Reply to
Anonymous

Why you should care has to do with the real quality of those TIG welds. A deteriorating tungsten tends to shed bits into the weld pool. These are called tungsten inclusions. Under stress then can promote weld failure because they don't blend with the surrounding steel. The best analogy I have come up with is marbles in cookie dough. If you deform the cookie dough it will tear where the marbles are.

First try going to a larger tungsten. Second try a higher heat tungsten, such as 1.5% or (even better) 2% Lanthanated.

Third go to a hand controller for you torch when in confined spaces.

Lincoln sells hand controllers that velcro to your TIG torch. CK Worldwide also makes several options.

Reply to
Ernie Leimkuhler

Mr. Leimkuhler (what a name!) has already answered your questions: The inclusions are bad.

But I wanted to po> ...a ball at the end of the tungsen the first time I touch the tungsten to

Well, don't do that! :)

Seriously, though: I haven't done a TIG weld in over 15 years! I wonder why these places sell special tungsten grinding tools. We always went over to the bench grinder, formed a quick point, and went about our welding! What's with these fancy grinding tools?

Reply to
jp2express

John - I was guessing as to your problem and came up with contamination by touching the weld pool then you confirmed my theory by stating "...first time I touch the tungsten to the puddel"

Not good - the pointy tungston should never touch the work! - hover above the work 1/8" to 3/16" Also, you do have Argon gas flowing at a repectable rate, don't you? Welding with no gas will also produce the results you mention

Good luck

Tom

Reply to
surftom

The really fancy ones have to do with breathing tungsten dust.

The most common DC TIG tungstens around are 2% Thoriated. Thoria is a radioactive alpha emitter. Not hugely carcinogenic, but not a great thing to have in your lungs. The fanciest tungsten grinders capture the dust in a kerosene bath.

Other tungstens lack the radioactive properties of Thoria.

Most tungsten grinders allow you to set a precise grind angle for more consistent welds.

I use a pedestal grinder or belt grinder to rough my tungstens and a find diamond wheel grinder for finishing. Mine is actually an old Darex Reamer sharpener I stripped down to just the motor and wheel.

Reply to
Ernie Leimkuhler

when I worked in aircraft repair I would sharpen on a grinding wheel,then polish the tungsten on the back (smooth) side of a belt sander for delicate low voltage thin gauge work.

Reply to
digitalmaster

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