TIG Tungsten Types Compared: Which Color Band for Which Job

For DC work on steel and stainless, a ceriated, lanthanated or thoriated tungsten ground to a point is the usual pick, and for AC work on aluminum, pure or zirconiated tungsten with a blunter tip is the traditional choice. The color band tells you the type, but the colors differ between standards, so read the printed class on the electrode. Check your machine manual before assuming a type suits it.

What a tungsten electrode does

In TIG welding the tungsten electrode carries the current and holds the arc, but it is not meant to melt into the weld. Tungsten has the highest melting point of any pure metal, so it erodes slowly rather than being consumed. The alloy added to it, usually a small amount of an oxide, changes how easily the arc starts, how steady it runs and how well the tip holds its shape.

That is the whole reason there are several types. They are standardized by AWS A5.12 and ISO 6848, which is where the color bands come from. Our TIG welding gear page collects the rest of the TIG kit.

The common types in plain language

That summary comes from a general reference on gas tungsten arc welding, which describes the types in these terms. Ceriated and lanthanated electrodes behave similarly and are non-radioactive, which is why many hobbyists pick them over thoriated. Where a table says "typical use", treat it as a starting point and not a rule, since the electrode maker's guidance for your amperage and machine matters more.

What the color band means, and why it can mislead

Tungsten electrodes are marked with a color band at one end. Pure tungsten is green and 2 percent thoriated is red in both the ISO and AWS systems. Other colors differ: the same general reference lists 2 percent ceriated as gray under ISO but orange under AWS, and 2 percent lanthanated as sky-blue under ISO but blue under AWS.

So two electrodes of the same type can wear different colors. The printed class or type on the electrode or its box is more reliable than the color alone. Buy from a supplier who states the type and standard on the packaging, and keep electrodes in their labelled tube so that a stray bare rod never goes into the torch as a mystery.

AC versus DC: how to choose

The reference lists the basic pairings. For AC, which is the setting for aluminum and magnesium, pure or zirconiated electrodes are preferred over thoriated ones, since thoriated electrodes are more likely to spit particles into the weld, and blunt tips are recommended. For DC electrode negative, which suits steels, nickel and titanium, thoriated electrodes ground to a sharp point are recommended. DC electrode positive is mainly for shallow welds, usually on thin metal with a thoriated electrode and pure argon.

• DC on steel or stainless: a pointed tip on a ceriated, lanthanated or thoriated electrode.
• AC on aluminum: pure or zirconiated, or whichever type your machine maker recommends, with a rounded or blunt tip.
• One electrode for everything: some welders use a single all-round type across AC and DC. Check your machine manual, because some inverter machines recommend particular types and tip shapes.

Our guide to welding aluminum and stainless welding guide cover the technique side.

Tip shape and grinding

The type is only half the story. The tip shape controls arc focus, and the grind direction affects arc stability. A sharp point suits DC on steel, and a blunter or lightly rounded tip suits AC. Grind lengthwise, not across, and use a dedicated wheel or grinder for tungsten so that it does not pick up contamination. Our tungsten grinder guide compares the purpose-built options, and the TIG consumable kit guide covers cups, collets and gas lenses that must match the electrode diameter.

Do not dip the tungsten in the weld pool. A contaminated tip should be re-ground or cut back, and a smaller or larger diameter may suit the current better. Follow the diameter and current guidance from the electrode maker and your machine manual rather than a rule of thumb.

Buying checklist

• Confirm the type (pure, ceriated, lanthanated, zirconiated, thoriated) from the printed class, not the color alone.
• Match the diameter to your torch collet and collet body.
• Choose a type suited to AC or DC, whichever your project needs.
• Prefer non-thoriated types if you are concerned about grinding dust.
• Buy a small assortment first rather than a large lot of one type.

Common tungsten mistakes

• Mixing up electrodes. Once a bare rod is out of its tube, the color band may be ground away. Mark the tube and store each type separately.
• Using the wrong diameter. A diameter that does not match the collet gives a poor grip and poor contact. Match the collet, then check the current guidance.
• Skipping the dust. Grinding creates fine dust. Grind where the dust is captured or blown away from you, particularly with thoriated tungsten.
• Grinding on a general-purpose wheel. A wheel that has seen steel and other metals can leave contamination on the tip. Use a dedicated wheel or tungsten grinder.
• Treating the color as the whole answer. Colors vary between systems and some makers add their own. Read the class.

Keeping a small labelled case of the two or three types you use is simpler than a drawer of loose rods. For where it sits in a shop, our tool storage article has ideas.