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Module 3: TIG/GTAW Operation

Overview

This module focuses on TIG (Tungsten Inert Gas) welding technique, emphasizing the unique skill of foot pedal control and coordination with the torch hand. Students will learn to select and prepare tungsten electrodes, set up and operate TIG equipment, coordinate left-hand filler rod feeding with right-hand (or torch-hand) torch manipulation, manage foot pedal control for current adjustment, and apply TIG technique to various joint geometries. TIG welding is the most skilled of the covered processes and requires significant hands-on practice.

Learning Objectives

  1. Select appropriate tungsten electrode type and size for given application
  2. Prepare tungsten electrodes (grind, contamination-free)
  3. Set up TIG torch, gas cup, and collet assembly
  4. Understand foot pedal control and adjust current during welding
  5. Coordinate filler rod feeding with torch movement
  6. Apply proper torch angle and travel speed for sound welds
  7. Troubleshoot TIG-specific defects (tungsten inclusions, lack of fusion, porosity)

Module Structure

  • Slide 1: Tungsten Electrode Selection & Preparation
  • Slide 2: TIG Equipment Setup (Torch, Collet, Cup, Gas Lens)
  • Slide 3: Foot Pedal Control & Current Management
  • Slide 4: Filler Rod Technique & Torch Coordination
  • Slide 5: TIG Technique for Different Positions & Joints

Assessment

  • Practical check: Tungsten electrode selection and grinding technique
  • Supervised welds on test coupons (flat, horizontal, vertical with filler)
  • Evaluation of foot pedal coordination (smooth current ramp up/down)
  • Assessment of filler rod feeding (consistency, heat input, bead uniformity)
  • Defect identification: Tungsten inclusions, lack of fusion, porosity

Time Allocation

  • Instructor Delivery: 3 hours
  • Hands-on Practice (High Volume): 6 hours
  • Troubleshooting & Assessment: 2 hours
  • Total Module Time: 11 hours

Prerequisites

  • Module 1: Welding Science Fundamentals
  • Some comfort with multi-axis coordination (foot pedal + both hands)

Resources

  • Operating GTAW (TIG) system with foot pedal and power supply
  • Tungsten electrodes (pure, 2% thoriated, 2% lanthanated; 1/16", 3/32", 1/8" diameters)
  • TIG torches and collets (various sizes)
  • Gas cups (standard, medium, large-cup diffuser configurations)
  • Gas lens assemblies
  • TIG filler rods (ER70S-2, ER308L, ER5356, various diameters)
  • Voltage/amperage parameter table for TIG
  • Test coupons (carbon steel, stainless, aluminum)
  • Tungsten grinding fixture (to maintain proper tip angle)
  • Measurement tools (filler gauge, depth gauge, visual inspection)
  • Defect reference photos

Module Version: 1.0 Created: 2026-03-15