Weird little balls on the tip of the tungsten

rayhall · Sat Dec 16, 2017 9:47 pm

Hello Everyone,

I have a new TIG welder (UNIMIG 200 AC/CD) and it has many knobs to change settings. I am welding Aluminium and the tungsten is getting small balls on the tip. What could be causing this.

Ray.

MinnesotaDave · Sun Dec 17, 2017 12:35 am

It also looks to be splitting lengthwise.

What type tungsten are you using? Amps? Balance? Diameter?

cj737 · Sun Dec 17, 2017 8:08 am

To Dave's point, it appears that you are snapping your tungsten which has caused fractures in its length. If you are using AC as the weld process, you don't want to use RED (thoriated) tungstens. Also, the AC balance will greatly effect the tip (looks like you're setup is wrong). Bundle those things together, and you get a tungsten that looks like that.

If you do need to alter the length of your tungsten, its best to grind it in half (use the edge of a grinding wheel to bevel it in two) then re-grind tapers into each segment. Snapping it, cutting, or shearing it will cause those micro splits.

rayhall · Wed Dec 27, 2017 9:01 pm

I have tried many settings and still get a problem with the tip of the tungsten. The big improvement was to go from 2% Thoriated to WZ8 Zirconiated. Not only did the tip problem improve, so did the welds.

I have the gas flow set to 10. I have tried pointed and rounded tip. The rounded gives the best result with WZ8 Zirconiated

Here is a picture of my current settings that I have found by trial and error. Also what the tip looks like now. Do they look correct for welding Aluminum ?

Ray.

cj737 · Wed Dec 27, 2017 9:12 pm

I prefer 2% lanthanated tungsten with an inverter. I start with a mostly sharp, tapered tip, then blunt it. I “ball it” by setting my balance to 30 until it balls (small, tight ball). Then I set my balance back to 70-75% and use 60-150hz for welding depending upon the application. I’ve never used Zirconium tungstens, so I have no clue about your settings.

MarkL · Wed Dec 27, 2017 10:52 pm

rayhall wrote:The big improvement was to go from 2% Thoriated to WZ8 Zirconiated. Not only did the tip problem improve, so did the welds.

My experience is zirconiated works good for AC on a transformer machine, but not very good on an inverter machine for either AC or DC. The ball on the tungsten should be more like the tip on a pencil that you've used for a long time, smoothly rounded off. The tungsten in your photo has a tip that looks irregular and not symmetric, almost like a blob of the aluminum got on it.