Tungsten Electrode Guide: Types, Color Codes, Grinding & Amperage Charts

Start with 2% lanthanated (blue band) tungsten in 3/32" diameter. It handles 50-180 amps on both AC and DC, works on every common metal, and holds a point better than pure or thoriated tungsten. For most hobbyists and small shop welders, a box of 3/32" lanthanated electrodes and a box of 1/16" for low-amperage work covers everything you’ll encounter.

Tungsten selection seems complicated because there are seven alloy types across three diameter ranges. In practice, two alloys and two diameters handle 90% of work. This guide covers what matters and skips the rest.

Tungsten Types by Color Code

Every tungsten electrode is color-coded by a painted band at one end. The color identifies the alloy. Here’s what each one does and when to use it.

2% Lanthanated (Blue Band): The Top Pick

Lanthanated tungsten is the best all-around choice for modern TIG welding. Here’s why:

• Starts easily with lift-start, scratch-start, and high-frequency ignition
• Maintains a sharp point on DC for long periods without erosion
• Handles AC aluminum without splitting (forms a clean ball at the tip)
• Available in all standard diameters
• No radioactivity concerns
• Slightly better current-carrying capacity than ceriated

If you’re buying one type of tungsten, buy lanthanated.

2% Ceriated (Gray Band): The Runner-Up

Ceriated tungsten performs almost identically to lanthanated with one advantage: slightly better arc stability at very low amperages (under 30A). This makes it the preferred choice for thin sheet metal work on 22 ga and thinner material.

The difference between ceriated and lanthanated is small. Many professional welders can’t tell them apart in a blind test. Either one is a good choice for a general-purpose shop.

2% Thoriated (Red Band): The Legacy Standard

Thoriated tungsten was the DC welding standard for decades. It holds a point well and handles high amperage. The problem is that thorium is mildly radioactive, and grinding thoriated tungsten creates radioactive dust.

The radioactivity level is low. Holding a thoriated tungsten won’t hurt you. But inhaling grinding dust is a real health concern over years of use. OSHA recommends ventilation and dust collection when grinding thoriated tungsten.

Lanthanated and ceriated match thoriated’s performance without the radioactivity. Most shops have switched. If you have a box of red band tungsten, it’s fine to use up, but don’t buy more.

Pure Tungsten (Green Band): AC Only

Pure tungsten was the original electrode for AC aluminum welding. It forms a stable ball on the tip during AC operation and handles the EP heating without splitting. On DC, it performs poorly: erratic arc, rapid tip erosion, poor point retention.

On modern inverter machines with adjustable AC balance and frequency, lanthanated and ceriated work better than pure tungsten even on AC. Pure tungsten is still useful on older transformer machines where the fixed 50/50 AC balance heats the electrode aggressively.

Tri-Mix and Rare Earth (Orange and Purple Bands)

Marketing-driven alternatives that blend multiple rare earth oxides. They work fine as general-purpose electrodes. Performance is similar to lanthanated. They don’t offer significant advantages over single-oxide electrodes, but they aren’t worse either.

Diameter Selection by Amperage

Match tungsten diameter to your amperage range. Using tungsten that’s too small for the amperage melts the tip. Using tungsten that’s too large wastes arc focus on low-amperage work.

The overlap between sizes gives you flexibility. At 100A, you could use a 3/32" or a 1/8" electrode. The 3/32" gives a more focused arc. The 1/8" runs cooler and lasts longer. Match to the situation: tighter joints benefit from the smaller tungsten’s focused arc, while long runs at sustained amperage benefit from the larger tungsten’s thermal capacity.

Grinding the Tungsten

Proper tungsten preparation directly affects arc stability, direction, and weld quality. A poorly ground tungsten wanders, spreads unevenly, and contaminates the weld.

Equipment

Use a dedicated grinding wheel for tungsten only. Options:

• Diamond wheel (best): Clean cuts, no contamination, lasts thousands of grinds
• Silicon carbide wheel (good): Works well, replace when glazed
• Bench grinder with fine wheel (acceptable): Dedicate one wheel to tungsten, mark it clearly

Never grind tungsten on a wheel used for steel. Steel particles embed in the wheel and transfer to the tungsten, contaminating every weld.

Grinding Direction

Grind lengthwise, holding the tungsten parallel to the wheel face and rotating it between your fingers. The grind lines must run parallel to the electrode, from base to tip.

Why direction matters: Grind lines running parallel to the electrode channel the arc in a stable, directional cone. Grind lines running around the circumference (from grinding perpendicular to the axis) create an unstable, wandering arc that spirals around the tip.

Taper Angle

The taper (grind) angle controls arc focus and heat distribution. Measured as the included angle of the point.

General rule: Start with a 30-degree included angle (taper length = 2x diameter). This works for most situations. Adjust sharper for thin material and precision, blunter for high amperage and wide beads.

Tip Preparation for DC

On DCEN, grind the tungsten to a sharp point. The sharper the point, the more focused the arc. A perfectly sharp point is ideal for low amperage (under 50A). For higher amperages, grind to a point and then lightly flat the very tip by touching it to a flat surface. This creates a tiny flat spot (called a “truncation” or “land”) that prevents the point from eroding and falling into the weld.

Truncation sizing: The flat tip should be about 10-20% of the electrode diameter. On a 3/32" tungsten, that’s about 0.010-0.020" flat.

Tip Preparation for AC

AC operation heats the tungsten more than DCEN because of the EP half-cycle. The tip will form a hemispherical ball during welding. On modern inverter machines with 65-75% EN balance, start with a pointed taper and let the ball form naturally. It will be small and stable.

On older transformer machines with 50/50 balance, pre-ball the tungsten by striking an arc on a copper block at low amperage until a round ball forms. The ball should be no larger than the electrode diameter.

Don’t use a pointed tungsten on a transformer AC machine. The point will melt and form an irregular blob that makes the arc wander. Don’t pre-ball a tungsten for an inverter machine. The sharp-ish point with a small ball that forms naturally gives better arc focus.

Collet and Collet Body Sizing

The collet must match the tungsten diameter exactly. A 3/32" tungsten needs a 3/32" collet. Using the wrong collet size causes poor electrical contact, overheating, and tungsten slipping during welding.

Most TIG torches come with a collet and collet body for one size. Buy collet sets for each tungsten diameter you use: 1/16" and 3/32" as a minimum, 1/8" if you weld thick material.

For gas lens collet bodies (which replace the standard collet body and provide better gas coverage), see the TIG cup size guide.

Tungsten Maintenance

When to Regrind

Regrind the tungsten when:

• The tip is contaminated (dipped into the puddle and picked up filler or base metal)
• The tip has eroded to a ball larger than desired on DC
• The arc wanders or becomes directionally unstable
• Visible oxidation or discoloration extends down the taper

How to Identify Contamination

A contaminated tungsten has visible metallic deposits on the tip. The color changes from the tungsten’s natural gray-silver to a darker shade with metallic blobs. On AC aluminum, a contaminated tungsten produces an erratic arc with inconsistent bead width and black speckles in the weld.

Fix: Break off the contaminated tip with pliers (hold the electrode in the collet and snap the tip off against a hard edge). Regrind from fresh material. If the contamination extends more than 1/4" up the electrode, cut the tip off with a cut-off wheel and regrind.

Extending Tungsten Life

• Keep adequate arc length (don’t dip the tungsten)
• Use enough post-flow gas to prevent tip oxidation
• Don’t exceed the amperage rating for the diameter
• Store tungsten in the original tube to prevent contamination
• Label pre-ground spares by angle and diameter for quick swaps

Keep Pre-Ground Spares Ready

Losing a tungsten tip to contamination during a complex joint is frustrating if you have to stop and grind a new one. Keep 2-3 pre-ground tungsten electrodes in a labeled tube next to your machine. Swap, resume welding, and regrind the contaminated one later.

Common Grinding Mistakes

Grinding Perpendicular to the Axis

This creates circumferential grind lines that make the arc rotate and wander. Always grind parallel, rotating the electrode between your fingers.

Inconsistent Taper

If one side is ground deeper than the other, the arc deflects toward the thinner side. Rotate the electrode evenly while grinding to create a symmetrical taper.

Contaminating the Grinding Wheel

Grinding tungsten on a wheel used for steel transfers steel particles to the tungsten surface. These particles enter the weld pool and create inclusions. Dedicate a wheel to tungsten and mark it clearly.

Too Sharp for the Amperage

A needle-sharp point on a 1/16" tungsten at 90A will melt within seconds and fall into the puddle. Match the point geometry to the amperage range. Higher amperage needs a blunter tip or larger tungsten.

Not Breaking Off Contaminated Tips

Some welders try to “burn off” contamination by running a high arc on scrap. This doesn’t work. Filler metal and base metal alloyed onto the tungsten tip don’t vaporize cleanly. They continue to contaminate the arc and deposit foreign material into subsequent welds. Break off the contaminated portion and regrind from clean tungsten.