Tungsten electrode colors: types and which to use
In TIG the tungsten does not burn away, but the type you pick and the shape of the tip change everything: arc stability, penetration and electrode life. The color band painted on the end tells you the composition, and the composition tells you which current it likes best.
The common all-round choices are lanthanated 2% (blue) and ceriated 2% (orange). They run on DC and AC. Pure tungsten (green) and zirconiated (brown) are for AC on aluminum. Thoriated (red) is excellent on DC but slightly radioactive, and many shops avoid it. Colors below follow AWS A5.12; ISO 6848 uses a different code.
Tungsten electrode color chart
| AWS | Color | Composition | Current | Main use |
|---|---|---|---|---|
| EWP | Green | Pure tungsten | AC | Aluminum and magnesium (AC) |
| EWTh-2 | Red | W + 2% ThO2 (thorium, radioactive) | DCEN | Steels, stainless, titanium; many shops now avoid it |
| EWCe-2 | Orange | W + 2% CeO2 | DC or AC | All-round, easy starts |
| EWLa-1.5 | Gold | W + 1.5% La2O3 | DC or AC | High quality, long life |
| EWLa-2 | Blue | W + 2% La2O3 | DC or AC | All-round, steel and aluminum |
| EWZr-1 | Brown | W + 1% ZrO2 | AC | Aluminum (AC) |
Table 5.1 of the e-book The Welder's Forge.
Three other AWS A5.12 classes show up in catalogs: EWLa-1 (black), EWTh-1 (yellow, also thoriated) and EWG (gray, general class with an unspecified additive). Colors follow AWS A5.12. The ISO 6848 color code differs (for example, ceriated is gray in ISO), so read the printed class on the electrode and not only the band, especially if you buy from different suppliers.
Thoriated, or lanthanated and ceriated?
Thoriated electrodes (EWTh-2, red) were the most used for DC work for decades, thanks to excellent DC performance. The catch is that thorium is slightly radioactive. Lanthanated (blue, gold) and ceriated (orange) electrodes perform comparably without that concern and have largely taken its place.
For a beginner, lanthanated or ceriated is the simplest answer: it serves steel and stainless on DCEN and, on machines with AC, aluminum as well.
When grinding tungsten, especially thoriated, use a grinder dedicated to it, with dust capture or exhaust, and do not breathe the dust. Wash your hands before eating. If you can choose, pick lanthanated or ceriated.
Which diameter to choose
Common sizes are .040 in (1.0 mm), 1/16 in (1.6 mm), 3/32 in (2.4 mm) and 1/8 in (3.2 mm). Diameter follows current: thin for low current and thin sheet, thicker as you raise the amps. For a starting current by thickness, see the TIG welding amperage chart; torch angles and the arc-length rule are in TIG welding for beginners.
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How to grind the tip
Pointed tip for DCEN (steel, stainless, titanium)
On DC with the electrode negative, grind the tip to a point. The arc stays concentrated and penetration increases. The taper length should be 2 to 3.5 times the electrode diameter.
- 1/16 in (1.6 mm) tungsten: taper of about 1/8–7/32 in (3.2–5.6 mm).
- 3/32 in (2.4 mm) tungsten: taper of about 3/16–5/16 in (4.8–8 mm).
- 1/8 in (3.2 mm) tungsten: taper of about 1/4–7/16 in (6.4–11.2 mm).
Always grind lengthwise, with the grind marks running along the electrode toward the tip, never around it. That keeps the arc straight and stable.
Balled tip for AC (aluminum, magnesium)
On AC, the current itself rounds the tip into a small ball. The ball should not exceed 1.5 times the electrode diameter. If it grows larger, the arc turns wide and unstable, a sign of too much current for that diameter. More on AC in how to weld aluminum.
Bands wear off, and different suppliers do not always follow the same code. Keep unused electrodes in their labeled tube and write the class on the tube you are using. If you mix up two classes, grind a short piece and test it on scrap.
Contamination: the most common mistake
Tungsten gets contaminated when it touches the puddle or when the filler rod enters the arc. Metal sticks to the tip, the arc jumps around and the bead comes out dark and dirty.
- Stop welding as soon as you feel the arc change.
- Remove the contaminated part: break off or grind the tip until the tungsten is clean.
- Regrind with the right geometry.
- Check that gas keeps flowing after the arc stops (post-flow) so the tip cools under shielding.
If the tip turns blue or dark without ever touching the puddle, shielding is too weak: check the gas flow (15–20 CFH, or 7–9 L/min, is a typical starting point) and look for drafts.
Frequently asked questions
What is the best tungsten for a beginner?
What tungsten do you use for aluminum?
Is red tungsten dangerous?
How long should a ground tungsten tip be?
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