[tungstendipper]

Being new to TIG welding, and almost through my second tank of argon, I have only used a 3/32 electrode.
I've welded thin stainless, thin aluminum and steel; always using a 3/32 electrode. Using a 200 amp., inverter machine, and being able to sharpen a finer point on the electrode, it seems unnecessary to use anything else. Even Jody welds razor blades with 3/32 electrodes. When should I use something else? Is a 1/16 more precise, less heat? What do you use?

[Arclight Ironworks]

Our Force Majeur for ferrous/non-ferrous materials is a 3.2mm (1/8in) Tungsten. RED for ferrous, BLUE for non-ferrous, and CREAM for special apps. 90% of the Tungsten manufactured by DGP (German).

On occasion, we'll use 2.4mm (3/32in) in RED and BLUE. Ejected the use of 1.6mm (1/16in) long ago. Our typical materials for TIG weldout range in thickness from 0.5mm (0.020") to 9.5mm (3/8"). Non-pulsed, pulsed, and pseudo-orbital.

2.4mm in BLUE tends to 'breaks down' at the tip for us, even at mid-range amperages, while welding Aluminum. Especially at protracted duty cycles (ie. longer runs). Using 3.2mm in BLUE eliminates that problem, based on our experiences.

From an O&M perspective, having a single sized Tungsten allows us to minimize the assortment of torch components (ie. collets, gas lens body, collet body, gas lense shielding cups, and standard shielding cups). This translates not only to a co$t saving$, but also to smoothing out the time required to change components and configure the torch for arclight.

Our weps include CK Worldwide 17/18 series and HTP 17 series valved torches. The Key is to understand how to properly profile/shape the tip of the Tungsten based on your material thickness/composition.

A video is worth a thousand images, goes the saying. Watch Aaron (http://www.6061.com) prove this point in his nicely produced YT productions:

* part I: http://www.youtube.com/watch?v=-GJBESqEvLY
* part II: http://www.youtube.com/watch?v=-L1UgdtpCpw

P.S. Aaron's online training is worth it's weight in Platinum.

[bruce991]

3/32 2% Lanthanated is my normal and most used I tried a 1/16 in once and is not suitable for the amperage's I run.

[Oscar]

The Key is to understand how to properly profile/shape the tip of the Tungsten based on your material thickness/composition.

That is indeed the key. There are uses for different sized tungstens; if there weren't they wouldn't still exist. Arc starts sometimes play a role. Thicker tungstens can [sometimes] not have crisp low-amperage arc starts. Do you always need crisp, low-amperage arc starts? No. Might you sometimes/someday? Who knows, maybe. If and when you do, that's when a smaller tungsten can be beneficial.

[pgk]

+1 for Aaron, that guy lays down some amazing beads, most all with 1/8th electrodes ...

[LtBadd]

Aluminum more so then other materials you can (and usually need) a larger electrode, I've done a lot od TIGing with .040" and 1/16" tungsten, really depends on whats being welded

I also think that with the inverter tech now in most machines, the arc starting is much better.

[Louie1961]

I use a 3/32 2% Lanthanated (blue) tungsten for all steels as I never need to get above 200 amps. For aluminum I always use a 1/8 2% lanthanated (blue). If I need to do thin stuff I re-profile the point to something sharper, thick stuff I use a truncated point kind of reminiscent of a crayola crayon. Never had a need for anything different

[entity-unknown]

ArcLight and Oscar! SOLID advice! If there was an upvote I'd do that but I'll "waste" a post for say THANK YOU!

[entity-unknown]

This has been bothering me since I read this post....

So most of my failures with Al has been due to too deep of penetration. Most of my welds were very wide and made arc control difficult where I'd have to start out real heavy on the pedal then taper off to almost nothing on the pedal for a good consistent weld.

In every situation I've made my tungsten grind to the equiv of the shape of pencil lead after you've finished with a fine point pencil sharpener. Recalling the arc width, it was VERY wide but I just assumed that was normal....

So what I'm gathering here is I've been doing it wrong all along (not the first time).

Recap: Are we saying a tungsten grind that matches a sharpened fine point pencil is bad for Al and instead I need a flattened end? I see the pics and that's exactly what I'm reading, just confirming a n00b's dumb ?

[tungstendipper]

Recap: Are we saying a tungsten grind that matches a sharpened fine point pencil is bad for Al and instead I need a flattened end? I see the pics and that's exactly what I'm reading, just confirming a n00b's dumb ?

This is the kind of questions I hope this thread would bring. Keep it going I'm learning a lot.

BTW...For what purpose would you use 1/8 tungsten on all thickness of aluminum? It make no sense to me. I can see it used on 1/4" and thicker.
Thanks for all that posted!!! Good stuff!

[Arclight Ironworks]

....Recap: Are we saying a tungsten grind that matches a sharpened fine point pencil is bad for Al and instead I need a flattened end?...

For the majority of cases, you'll optimize the Tungsten's arc stability and cathodic penetration effects by properly preparing and profiling the included angle to subtend ~ 30-45-60deg. An an option, you may slightly blunt the Tungsten's tip. In most cases, blunting the tip prior to welding out Aluminum aids in combating disintegration at the tip that primarily results from evaporation at LTE (local thermal equalibirum) within the plasma column during electron/ionic transfer. Note that blunting, if used for aluminum, should be small/small unlike shown in the image. IMPO. Using a larger diameter Tungsten (ie. 1/8") with REMs (rare-earth metal oxides), the propensity for erosion of the Tungsten {thermionic cathode} is significantly diminished sans a blunt tip. Lastly, there are certain cases where we profile the tip with two separate included angles.

The image, captured from the body of literature, represent what we employ 90+ percent of the time for steel/stainless steel and aluminum. Again, with a smaller blunting (if used). We profile based on our application (i.e. joint geometry, position, etc), the type/thickness of the materials to be welded, and the filler selected.

You have to "test and learn" and determine what works for your welding style and your application.

Tungsten Profiles.png (194.4 KiB) Viewed 3028 times

"For a cathode to support an arc, some process must exist which provides current continuity at the cathode-plasma boundary. To escape from the metal the electrons should either overcome an energy barrier that exists at the cathode-plasma boundary (work function) or tunnel through this barrier. The first process is thermionic electron emission. It requires a hot cathode temperature for a substantial number of electrons to be emitted. The second process, field electron emission, requires high electric fields at the cathode surface to make the barrier low and thin and thus intensify electron tunneling. In the considered type of arc, the intermediate case takes place: the cathode is hot and its work function is lowered by a strong electric field at the surface (the Schottky Effect). Both factors (hot cathode and high electric field) play important roles in the electron emission process in thermionic arcs. However,the electric field while being strong enough to reduce thework function is not strong enough to provide any substantial electron tunneling." (Valerian Nemchinsky, 2014).

[entity-unknown]

So thinkin about this a bit more, I want to expand on my question... it really depends on the thickness and penetration. But for a poor man's example, I'd say a fine point for thick, deep penetration, and a fairly flat end for more fine work? Basically exactly opposite of what I'd expect from drawing with a pencil?

Edit 1: And I see ArcLight provided a very detailed explanation after I posted this Reading now.

Edit 2: So after reading the post, I think I actually comprehend what's going on. I'd say I'm a 30 to 45 degree'er usually I honestly have always approached this with the concept of drawing with a pencil but what I should be thinking of is how the surface of the tungsten tip aligns to the welding area.

So if you were all my professors (I pretend you are ) these are the three ?s I'd ask to confirm what I read from ArcLight above:
So the sharper the tip, the less parallel the tip surface where the electrons leave the electrode is to the welding area, then the result is a wider arc which would equate to more heat with less initial penetration, so more heat is required to weld? Kinda like having a really bad arc gap and/or torch angle?

Then without getting too deep into the angles, the more blunt tip will provide more focused arc/heat with deeper penetration per second with the ability to control arc width by controlling the angle of the tip i.e. sharper = wider ?

Lastly, a 90 degree torch angle is more important with a sharper tip than a blunt i.e. the blunt tip gives more room for torch angle with less negative impact to your weld in comparison ? Does this also give flexibility with arc gap?

[mechanic416]

I use 3/32" most of the time as I am welding from 80 to 150 amps. I use red, blue and purple as I have found they all weld steel and aluminum about the same. I sharpen my 3/32 and 1/8 to what ever looks good. I do not sharpen my .020, .040 or 1/16 most of the time, depending on what I am welding.