Slide 001: TIG Welding Equipment & Tungsten Preparation

Slide Visual

Slide Overview

This slide introduces the TIG welding system components, tungsten electrode types, and the critical skill of tungsten preparation. Proper equipment knowledge and tungsten preparation are prerequisites for any TIG welding.

Instruction Notes

TIG System Components

Power Supply: TIG welders are constant-current (CC) machines — the operator sets maximum amperage, and the machine maintains consistent current regardless of arc length variations. Advanced inverter machines offer: AC/DC selection, AC balance control, AC frequency control, pulse settings, and programmable sequences.

TIG Torch: Available in air-cooled (up to ~200A) and water-cooled (200A+) configurations. - Collet: Holds the tungsten electrode — size must match electrode diameter - Collet body: Seats inside the torch head, provides gas flow path - Cup (nozzle): Ceramic or glass, directs shielding gas. Sizes: #4 (¼"), #5 (5/16"), #6 (⅜"), #7 (7/16"), #8 (½"). Larger cups provide better coverage - Gas lens (optional): Replaces standard collet body for laminar gas flow - Back cap: Threads onto the torch body, varies in length (short, medium, long) for electrode stick-out and torch clearance

Foot Pedal: Provides variable amperage control from 0 to the machine's set maximum. Full press = full amps. Partial press = proportional amps. This real-time control is the defining feature of TIG welding.

Filler Rods: 36" straight rods, hand-fed. Store in a rod tube to keep clean.

Tungsten Electrode Types

Type	Color Band	Best For	Grind To
Pure (99.5% W)	Green	AC aluminum welding	Ball forms naturally on AC
2% Thoriated	Red	DC steel/stainless (most common)	Sharp point
2% Lanthanated	Blue	DC and AC — all-purpose	Sharp point (DC) or balled (AC)
2% Ceriated	Orange	DC low-amp, AC aluminum	Point or ball
Tri-mix (rare earth)	Various	General purpose	Point or ball

Common sizes: 1/16", 3/32", ⅛". Use 1/16" for thin material (<16 ga), 3/32" for general use, ⅛" for thick material or high amps.

Tungsten Grinding Procedure

1. Use a dedicated grinding wheel — never use a wheel that has ground steel (contamination transfers to tungsten, then to the weld)
2. Hold the tungsten parallel to the wheel face, rotating it between your fingers as you grind
3. Grinding marks must run lengthwise (along the electrode) — cross-grinding causes the arc to wander
4. Taper length: 2–2.5× the electrode diameter (e.g., 3/32" electrode → 3/16"–15/64" taper)
5. Leave a tiny flat at the tip (~0.010"–0.020") for arc stability and longer tip life
6. For AC (aluminum): start with a point, then allow the arc to form a small ball during welding

Safety Note on Thoriated Tungsten

2% thoriated tungsten contains thorium oxide — a low-level alpha emitter. The radiation risk during normal welding is negligible, but grinding produces thorium-contaminated dust. Use dedicated grinding wheel with dust collection, or use lanthanated tungsten as a non-radioactive alternative with equivalent performance.

Key Talking Points

1. TIG is constant-current — you set max amps, the foot pedal controls actual output
2. The foot pedal is your heat control — mastering it takes significant practice
3. Tungsten grinding direction matters — lengthwise marks direct the arc
4. Never grind tungsten on a wheel used for steel — contamination ruins welds
5. Lanthanated tungsten is the modern all-purpose choice — works on DC and AC

Learning Objectives (Concept Check)

• [ ] Identify all TIG system components and their functions
• [ ] Select the correct tungsten type and size for a given application
• [ ] Demonstrate proper tungsten grinding technique

---

Last Updated: 2026-03-19