200 amps - pedal controlled
120hz
35% balance - inverter machine
1/8" 2% Lanthanated Tungsten
#6 cup with a gas saver
1/8" 4043 filler
I attempted to ball the electrode on a piece of copper at 200 amps, and I couldn't get it to ball at all. The tungsten is ground using a brand new grinding wheel on a bench grinder and a drill. I am not sharpening them to a fine point, but a blunt end. The tungsten turns from blue to purple to gold, as you see in the picture. Any tips are definitely appreciated. I just started aluminum today.
Balling tungsten is a practice that has been used for many years to promote arc stability. Old habits die hard. Its not really need on modern welders. Make a small point, and grind a flat spot right on the tip, and let it do what it wants to naturally. To your question, those colours are caused by inadequate post gas flow, which means that gas isn't flowing long enough after the arc is finished while the tungsten is very hot. Turn the post flow up to 10 seconds and it should stay shiny silver.
In addition to what was said here, terminate your weld and keep the torch in place at the end of the weld while your post flow runs it's time out. This does two things, it cools your tungsten in the gas envelope and cools your weld keeping Oxygen at bay until the surface is through it's critical temps. This is not as important on Aluminum as it is on other metals, but it does keep the Argon being pushed back into the cup to keep the tungsten clean.
Lucky, if you just started Aluminum today, then you're definitely getting the hang of it.
Like Mike said, increase the post flow. That tungsten has to be cool before the gas stops.
The Fronius MagicWave 3000 has an automatic balling feature which they claim creates time savings - "simply clamp the sharpened electrode, pre-select cap diameter, the arc automatically forms the correct cap size" I've used one, it's rather unique.
However, like the guys said, modern inverter welders don't need to have a balled electrode. Your cleaning action looks consistent, so presumably you have reasonable arc stability (not too much arc wander)
Trevor
EWM Phonenix 355 Pulse MIG set mainly for Aluminum, CIGWeld 300Amp AC/DC TIG, TRANSMIG S3C 300 Amp MIG, etc, etc
Thanks for the tips. I want to be clear that the tungsten didn't do that when I tried to ball it, but throughout the welds. I don't know if you can see it from the pics, but it looks and feels kind of rough and spiky.
I did just start today, I have watched some videos before starting, which helped. I have welded with mig and stick a lot in the past, so it helps knowing what the puddle should be doing. Thanks for the kind words.
Lucky,
That seems to be more prevelent while using an inverter than an old transformer because the tungsten doesn't ball up. Usually the only time a transformer welder would do this is when you are at the upper limits of the tungsten. With an inverter you taper the tungsten down to a smaller size and then the end is essentially a 3/32 or even a 1/16" tungsten trying to handle the amps requiring a 1/8" one, so it splinters. If it has no ill effects on the weld don't sweat it, dress up the tungsten when it does.
The AC Balance may cause balling or blunting of the electrode during the DC+ side of the cycle. If you are running with your balance towards the electrode negative side, you may be able to keep the electrode nearly sharp. As you turn the balance towards the + side, the electrode will ball up more.
The tendency/need to ball the electrode is more related to the AC balance than the type of machine (inverter vs transformer)
Balling your electrode slightly before you begin the weld may minimize the changes during welding but I am not sure it will change much about your weld.
Gerald Austin
If I didn't say it in the post- Have a great day !
Greeneville Tn
I'm likely wrong, so take it with a grain of salt. I believe electrons like any other moving object don't want to turn corners if they don't have to. They will flow down the polished tungsten cylinder until they reach the end. At that time the ionized gas, (plasma?) is contained in a smaller area so more concentrated. Minnesota Dave has a chart he posts showing benefits of narrower more concentrated arc, producing narrower bead, less heat affected zone width, and deeper penetration, with more strength when the AC tungsten is barely tapered.
Conversely, the long taper on tungsten like you would use for DC EN will begin the visible arc as soon as the grind begins. Grind like a sharp pencil, the arc can be a blob of plasma 1/2" across! Secondary to other undesirable characteristics, the tungsten gets some weird shapes quickly. Taper only enough to clean contaminants off, with a rounded tip. It'll shrink back a bit, but not really ball.
Use only as much EP as you need for cleaning. EP half cycle can heat the tungsten excessively. The early sine wave welders were 50% EP, they needed a rounded tip for AC.
