TIG Tungsten Electrode Guide

What This Guide Covers

Five families of tungsten look almost identical in a box until you check the color band on the shank. Mixing them up costs you arc stability, tip life, or — with thoriated — an unnecessary radiation exposure question in the shop. Jump to any section:

1. Tungsten Types Explained

Every non-consumable TIG electrode is tungsten with a small percentage of oxide additive mixed in (or none, for pure tungsten). The additive changes electron emission, arc starting, current-carrying capacity, and tip life — not the base metal you're welding, which is a common misconception. Here is what each family actually is.

EWP — Pure Tungsten (Green)

99.5% tungsten, no oxide additive. Forms the cleanest, most rounded ball under AC and gives the smoothest, most stable arc cone for balanced-wave aluminum on older transformer-style AC/DC machines. Lower current-carrying capacity and shorter life than doped tungstens, and it's largely legacy on modern inverter machines that clean aluminum oxide efficiently with lanthanated tungsten instead.

EWTh-2 — Thoriated (Red)

1–2% thorium dioxide. For decades this was the default DCEN electrode for steel and stainless — excellent electron emission, easy arc starts, and a point that holds up well under load. The catch is thorium-232, a low-level radioactive material (see the phase-out section below). Thoriated is still sold and still legal to buy in most regions, but most shops and most modern manufacturer literature now steer new buyers toward lanthanated as the drop-in replacement.

EWCe-2 — Ceriated (Orange / sometimes grey band)

2% cerium oxide. Excellent low-amperage arc starts, including DC lift-arc starts without HF. Popular for thin-gauge sheet metal, small-diameter tube, and orbital/precision work where a stable start at low current matters more than peak amperage headroom. Runs a bit cooler at the top end than lanthanated of the same diameter.

EWLa-1.5 / EWLa-2 — Lanthanated (Gold / Blue)

1.5% (gold band) or 2% (blue band) lanthanum oxide. This is the modern, non-radioactive, do-everything replacement for thoriated. Comparable current capacity, comparable tip life, easy re-grinding, and it works acceptably on both DCEN (pointed) and AC (controlled ball) duty — which is exactly why most shops standardize on 2% lanthanated (blue) as their single default electrode.

EWG — Rare-Earth Blends (Purple / Teal / Grey, varies by brand)

Blended oxide packages (often lanthanum + cerium, or proprietary mixes) marketed as multi-process electrodes that run well on both AC and DC without swapping tungsten between jobs. Color convention is the least standardized of the group — always confirm against the box or a chart from the specific manufacturer, since "purple" from one brand may not match another.

2. Why Thoriated Is Being Phased Out

Thoriated tungsten (EWTh-2) contains thorium-232, which is radioactive — it decays extremely slowly (a multi-billion-year half-life) and emits low-level alpha and gamma radiation. A single electrode sitting in a torch or a drawer is not a meaningful exposure risk by itself. The concern is grinding dust.

Dry-grinding a thoriated tip aerosolizes fine tungsten-thorium particulate. Inhaled repeatedly over years — the realistic exposure pattern for a welder who grinds tungsten daily without controls — that dust is a genuine occupational health concern, which is why OSHA, NIOSH, and most fabrication shop safety programs now recommend (and in unionized/industrial settings often require) minimizing thoriated use and controlling grinding dust when it is used.

Practical shop response

• Dedicated grinder for thoriated only if any stock remains in the shop — never share a wheel between thoriated and other tungsten, and never use that wheel for anything else.
• Local exhaust ventilation or a HEPA-filtered grinding station for any thoriated grinding; do not dry-grind at an open bench with no capture.
• Wet grinding where the equipment supports it, to suppress airborne dust entirely.
• Switch new purchases to 2% lanthanated (blue) — it matches thoriated's arc performance closely enough that most welders don't notice a difference in daily work, with none of the radioactive dust question.
• Don't panic-discard old stock — finishing existing thoriated electrodes safely with proper grinding controls is fine; the issue is exposure management, not the electrode sitting in a drawer.

3. Tungsten Color-Code Reference Chart

Color bands are painted on the shank end so you can sort electrodes at a glance without a spark test. This follows the common AWS A5.12 convention used by most major US brands.

Diameter selection depends on amperage and polarity, not just material — undersized tungsten for the amperage is one of the leading causes of excessive tip consumption. Use the Tungsten Electrode Selector Calculator to match diameter to your actual amp range before you buy or re-grind.

4. Tip Prep: Pointed (DCEN) vs Balled (AC)

Tip geometry matters as much as tungsten type. A perfect lanthanated electrode with a bad grind will still wander and contaminate.

Pointed tip — DCEN steel & stainless

DCEN (electrode negative) focuses the arc through a sharp point for a narrow, penetrating arc cone. Prep it correctly:

• Grind longitudinally — flutes running lengthwise down the taper, in the same direction as electron flow. Never grind across the tip; crosswise scratches emit electrons unevenly and cause arc wander.
• Use a dedicated tungsten grinder with a diamond wheel, separate from any wheel used on steel — cross-contamination from a shared wheel embeds foreign material in the tip.
• Included angle: 15–30° for most work. Narrower angles (15–20°) give a more focused arc and deeper, narrower penetration — good for thin material and tight root passes. Wider angles (25–30°) carry more current before the tip erodes and suit thicker material at higher amps.
• Truncate the point (grind a small flat, roughly 10–20% of the diameter) when running near the top of that diameter's amperage range. A truncated tip sheds heat better and resists the point melting into a ball at high current — a common misdiagnosis that looks like "bad tungsten" but is really an amperage/geometry mismatch.

Balled tip — AC aluminum & magnesium

AC reverses polarity every half-cycle, and the electrode-positive half heats the tip enough to round it naturally. Fighting that with a sharp point on AC just means the point melts into an uneven ball anyway — so most welders start it deliberately:

• Grind a light point or square the end first, then strike an arc on clean copper or aluminum scrap at moderate amperage and let AC form the ball.
• Target a smooth, shiny hemisphere roughly 1–1.5x the electrode diameter. Bigger, lopsided, or "flowering" balls mean too much EP balance, too much amperage for the diameter, or contamination — see the electrode troubleshooting page for ball-shape diagnosis.
• Pure (green) and zirconiated (grey) ball the most predictably and resist contamination pickup, which is why they're still specified on some transformer-style AC machines.
• 2% lanthanated (blue) on modern inverters forms a controlled ball just fine on AC and lets you use one electrode type for both AC and DC duty — the reason most multi-process shops standardize on it instead of stocking separate pure/zirconiated tungsten.

Full settings context — amperage, balance, and frequency for pointed vs balled duty — lives in the TIG Settings Guide, the Stainless TIG Guide, and the Aluminum TIG Guide.

5. Stick-Out and Gas Cup Basics

Tip prep only pays off if the electrode is positioned and shielded correctly:

• Stick-out (electrode extension past the cup): roughly the electrode diameter for tight fillets and corners; up to about 1.5x diameter for open, flat-position work where you need visibility. Too much stick-out puts the hot tip outside effective gas coverage and invites discoloration.
• Cup selection: standard ceramic cups work for general DC work; larger cups or gas lenses give a wider, laminar shield — useful for stainless HAZ control and aluminum where oxide re-forms fast without full coverage.
• Collet body match: the collet body must match electrode diameter exactly — a mismatched collet lets the electrode wobble in the torch, which reads exactly like a bad grind (arc wander) even with a perfect tip.