TIG tungsten electrodes: colors, sizes, and grinding
What the color bands mean, which electrode suits which job, how to size it to the current, and how to grind a point that steers the arc where you aim it.
The tungsten is the smallest part of a TIG setup and the one that decides most about how the arc behaves. Pick the wrong one and it will not start reliably, will not hold a point, or will drop into the weld pool. Pick the right one and grind it badly, and the arc will point somewhere other than where the torch does.
What the colors mean
Tungsten on its own works, but adding a small percentage of a metal oxide improves how the electrode emits electrons — it starts more easily, runs cooler at the tip, and lasts longer. The color band on the end says which oxide was added.
| Band | Designation | Oxide | Where it belongs |
|---|---|---|---|
| Green | EWP / WP | none — pure tungsten | AC on older transformer machines; balls readily |
| Red | EWTh-2 / WT20 | 2% thorium | Long the DC standard; radioactive dust when ground |
| Gold | EWLa-1.5 / WL15 | 1.5% lanthanum | Good all-rounder, AC and DC |
| Blue | EWLa-2 / WL20 | 2% lanthanum | The modern default: AC and DC, holds a point |
| Orange or grey | EWCe-2 / WC20 | 2% cerium | Excellent low-current starting, AC and DC |
| Brown | EWZr-1 / WZ8 | zirconium | Specifically for AC; forms a stable ball, resists spitting |
One caution about the colors. AWS A5.12 and ISO 6848 do not agree on every band, and some suppliers use their own for proprietary rare-earth blends. The printed designation — WL20, EWLa-2 — is the identifier that does not change. Read it before trusting the paint.
Which one to actually buy
For a shop with a modern inverter and a mix of work, 2% lanthanated (blue) is the single most useful electrode. It runs on AC and DC, starts at low current, keeps a ground point instead of balling up, carries current comparable to thoriated, and contains nothing radioactive.
Ceriated is the other sound all-rounder, and it is better than lanthanated at very low amperage — thin sheet, delicate repair, orbital heads running small currents.
Thoriated (red) still performs well on DC and is still widely stocked. The objection is not performance but the grinding dust: thorium-232 is radioactive, and grinding produces respirable particles. If it is in use, grind with extraction, never on an open bench wheel shared with other work.
Pure tungsten (green) and zirconiated (brown) belong to AC on transformer machines, where the electrode is meant to form and hold a ball. On an inverter with balance control they are rarely the best choice.
Sizing to the current
An electrode too large for the current gives an unstable arc that wanders around the tip. Too small, and the tip overheats, erodes and eventually drops into the pool.
| Diameter | DC electrode negative | AC |
|---|---|---|
| 1.0 mm | up to ~80 A | up to ~55 A |
| 1.6 mm | up to ~145 A | up to ~100 A |
| 2.4 mm | up to ~250 A | up to ~160 A |
| 3.2 mm | up to ~400 A | up to ~250 A |
The AC column is lower throughout because the electrode-positive half of each cycle heats the tip. That is also why AC work usually calls for one size up from what the same current would need on DC.
Treat these as typical ranges. Manufacturers publish their own figures, and they vary with the oxide, the gas and how far the electrode sticks out of the cup.
Grinding: the part that gets skipped
Grind lengthwise, along the axis of the electrode. This is the single most consequential detail on this page. The current follows the grinding marks: ground across the electrode, the arc wanders sideways and no amount of torch technique corrects it. Ground along it, the arc goes where the point aims.
Taper length: roughly two to two and a half times the diameter. Longer tapers focus the arc more tightly and suit thin material and low current; shorter, blunter tapers carry more current and last longer.
Leave a small flat on the tip. A needle point looks right and disappears in seconds at working current — the tip melts and goes into the weld. A truncated tip, a few tenths of a millimeter across, is what survives.
Keep a wheel for tungsten only. A wheel that has touched steel will embed iron in the electrode, which contaminates the weld. A diamond wheel or a dedicated tungsten grinder is worth the money in a shop that welds stainless or aluminum.
When you dip it, stop. Touching the pool contaminates the tungsten instantly. The contaminated end has to be broken off and reground — grinding it back without removing the contaminated material just spreads it.
Stick-out and cup
The electrode should extend beyond the cup by roughly its own diameter for a butt joint, and up to about twice that for a fillet where access demands it. Further out than the shielding envelope reaches, and the tip oxidizes — visible afterwards as a dull, discolored electrode.
A gas lens extends the usable stick-out considerably by turning turbulent flow into a smooth column. On work with awkward access it is the difference between reaching the joint and shielding it properly.
What TIP TIG uses
Nothing special — and that is deliberate. TIP TIG runs a conventional TIG torch on a conventional TIG power source, so the electrode, the collet, the cup and the gas are what the shop already stocks. What is added is the wire: a separate feeder delivers filler that has been heated close to melting point, mechanically oscillated into the pool.
That matters for consumables in one respect. Because the arc does not have to melt cold filler, it works less hard for the same deposit — and an electrode that runs cooler holds its ground point longer. The process page covers how the hot wire side works.
In short
Blue (2% lanthanated) covers most work on a modern machine; ceriated is better at very low current; thoriated performs but brings a dust hazard you do not need. Read the printed designation rather than trusting the paint, since AWS and ISO colors differ. Size the electrode to the current, and one size up for AC. And grind along the axis with a small flat on the tip — that single habit fixes more arc problems than any setting on the machine.