TIG Tungsten Guide: Pure vs Thoriated and Grinding Angles
By MIG/TIG/Stick Welders & Plasma Cutters | USA Weld – HTP ... | Published: 2026-10-15
Category: How-to Guides
Learn how to choose and prep TIG tungsten: pure vs thoriated, color chart, grinding angle, and size for the job. A step-by-step guide with common mistakes.
Quick answer
For most TIG welding on steel and stainless, use a thoriated (red) or ceriated (gray) tungsten with a 20–30° tapered point. Pure (green) tungsten is best for aluminum on AC. Match tungsten diameter to amperage, grind lengthwise, and keep a dedicated wheel for tungsten only.
Match tungsten type to your process and material
The TIG tungsten color chart is your quick reference: green is pure, red is thoriated (2% thorium), gray is ceriated (2% cerium), gold is lanthanated (1.5% lanthanum), and blue is lanthanated (2%). For DCEN welding on steel, stainless, and nickel, thoriated or ceriated tungsten holds a point well and starts reliably. For AC welding on aluminum, pure tungsten balls up and provides a stable arc, but many welders now prefer lanthanated or ceriated for better amperage capacity. If you need a balled tip for AC, pure is the traditional choice; if you want less frustration, try lanthanated.
Choose the right tungsten diameter for your amperage
Tungsten diameter controls how much current it can carry without spitting or melting. As a starting point: 1/16 in (1.6 mm) for 70–150 A, 3/32 in (2.4 mm) for 150–250 A, and 1/8 in (3.2 mm) for 250–400 A. These ranges vary with tungsten type and shielding gas, but they keep you in the ballpark. If your tungsten balls up or the arc wanders on DC, you are likely running too much current for the diameter or have the wrong type.
Grind the point lengthwise with a dedicated wheel
The grind angle and direction matter more than most beginners expect. A 20–30° taper is a good all-purpose point for DC welding. Grind parallel to the tungsten axis (lengthwise), not perpendicular. Grinding across the tungsten leaves scratches that can make the arc wander. Use a dedicated grinding wheel for tungsten only—contamination from steel or aluminum will ruin the point and the weld. A fine-grit wheel (around 100–120 grit) gives a smooth finish. For aluminum on AC, you can leave a blunt tip or ball it slightly; a sharp point will ball on its own.
Tungsten prep in 5 steps
- Select tungsten type: For DC on steel/stainless, choose thoriated (red) or ceriated (gray). For AC on aluminum, choose pure (green) if you want a balled tip, or lanthanated (gold/blue) for better performance. Checkpoint: If you are unsure, start with 2% thoriated for DC and pure for AC.
- Match diameter to amperage: Use 1/16 in for up to 150 A, 3/32 in for 150–250 A, and 1/8 in for 250–400 A. Consult your machine’s chart for exact limits. Mistake to avoid: Running a thin tungsten at high amperage causes it to spit and contaminate the weld.
- Grind lengthwise at 20–30°: Use a dedicated fine-grit wheel. Hold the tungsten nearly parallel to the wheel face and rotate it to create a smooth taper. Stop before the point gets too long—about 2.5 times the diameter is a good rule. Checkpoint: A properly ground point has no crosswise scratches and a sharp, centered tip.
- Ball the tip for AC (if needed): For aluminum on AC with pure tungsten, strike an arc on a scrap piece at your welding amperage until the tip balls to about the diameter of the tungsten. For inverter machines, many welders skip balling and use a slightly blunt point. Mistake to avoid: Over-balling creates a large molten drop that can fall into the weld.
- Install and set stick-out: Tighten the collet body so the tungsten is secure. Set stick-out to about 3–6 mm (1/8–1/4 in) for most joints. Too little stick-out risks arc strikes on the cup; too much reduces shielding. Next step: After welding, inspect the tip. If it is discolored or deformed, regrind before the next pass.
Product facts
- Heavy-duty consumable kit for the HTP America® 36 Series MIG welding gun.: Heavy-duty consumable kit for the HTP America® 36 Series MIG welding gun. The 36 Series MIG welding gun is an option with the HTP America® Pro PulseTM 300, and the 36 Series MIG welding gun comes standard on the following Everlast machines: Power i-MIG 275P and Power i-MIG 275S. The diffuser can be white or black. The kit comes in a compartmentalized box and includes the following parts: Part Number Description... If you run a 36 Series MIG gun, this kit keeps spare consumables organized and on hand, reducing downtime when a nozzle or contact tip fails mid-project.
- 5/8-18 LH Female to 9mm QD Male Water Adapter: Use this fitting to make your 20 series torch with 5/8-18 LH end into a quick connect fitting. This piece threads on so that you can use your water cooled tig torch with the 5/8 -18 LH fitting with a water cooler that has quick connects without permanently modifying your torch. You will need two of these fitting-one for the blue cable and one for the water return line. Equivalent to WDWAP A quick-connect adapter lets you swap water-cooled TIG torches without draining or modifying your cooler, which is handy when moving between projects or torch sizes.
