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Activity 001: TIG Welding — Dry Run & First Beads

Activity ID: U6M3-ACT-001 Duration: 45 minutes Objective: Students will practice TIG torch control, filler rod technique, and foot pedal operation through dry runs (no arc) followed by first beads on mild steel. Group Size: 2 students (one practices, one observes)

Overview

TIG welding demands simultaneous three-limb coordination. This activity breaks the skill into components: first practicing torch and filler rod movement without an arc, then adding the foot pedal, and finally welding actual beads. This progressive approach builds confidence and reduces tungsten contamination.

Materials & Equipment Needed

  • TIG welder (DC, set for steel)
  • 3/32" 2% lanthanated tungsten electrode (pre-ground to a point)
  • 3/32" ER70S-2 filler rod (3 rods per student)

  • 7 ceramic cup, gas lens recommended

  • 4 mild steel plates: ⅛" × 3" × 6" (2 per student)
  • Foot pedal
  • Argon gas (20 CFH flow)
  • Dedicated tungsten grinding wheel
  • Wire brush
  • Full PPE: welding helmet (shade 8-10), FR jacket, TIG gloves (thin leather), boots, respirator, welding cap
  • Fire extinguisher within 15 feet

Instructions & Procedure

Phase 1: Dry Run — No Arc (10 minutes)

Without the machine on: 1. Sit at the welding table. Position comfortably — feet flat, dominant hand holding torch, non-dominant hand holding a filler rod 2. Practice the torch hold: pencil grip, rest forearm on table for stability 3. Hold the torch at 15°-20° trailing angle, simulating an arc length of ~3/32" from the plate surface 4. Practice advancing the torch at a slow, steady pace (3-4 inches per minute) 5. Now practice the filler rod dip: hold the rod at 15°-20° to the plate, dip the tip to the surface where the pool would be, then withdraw 6. Combine: advance torch → dip rod → withdraw rod → advance torch → dip rod → repeat 7. Do this for 3 minutes until the rhythm feels natural 8. Now add the foot pedal: practice pressing gradually (ramp up), holding steady, and releasing gradually (ramp down) 9. Combine all three: torch movement + filler dipping + foot pedal pressure

Phase 2: Arc Practice — Fusion Beads (No Filler) (10 minutes) 1. Turn on the machine: DCEN, 100A maximum, 20 CFH argon 2. Prepare the steel plate (grind to bright metal, mark guide lines) 3. Position the tungsten ~3/32" above the start of a guide line 4. Drop helmet, press the foot pedal gradually 5. Watch the base metal — a shiny puddle will form 6. Begin traveling forward, moving the puddle along the line at 3-4 IPM 7. Maintain consistent arc length (3/32") and puddle size 8. At the end, gradually release the foot pedal (2-3 second ramp-down) 9. Hold torch in place for post-flow (8-10 seconds) 10. Run 3-4 fusion beads (no filler) — focus on consistent puddle size and travel speed

Phase 3: Beads with Filler Rod (20 minutes) 1. On a fresh plate (or unused area), start a new bead 2. Establish the puddle (foot pedal ramp-up) 3. Once the puddle is established, begin the dip-and-withdraw rhythm: - Advance torch one puddle-width - Dip the filler rod into the leading edge of the puddle - Withdraw the rod (keep within 1" of the puddle — inside the gas shield) - Advance the torch again - Repeat 4. Maintain steady foot pedal pressure throughout 5. Run 4-6 beads with filler, each time trying to improve: - Even ripple spacing (indicates consistent dip timing) - Consistent bead width - Proper reinforcement (slight crown, not too tall, not concave) 6. If the tungsten gets contaminated (touches pool): stop, break off the contaminated section, re-grind, and continue

Phase 4: Evaluation (5 minutes) 1. Wire brush all beads 2. Compare fusion beads (no filler) to beads with filler 3. Identify your best bead: what made it better than the others? 4. Measure bead width consistency and ripple spacing

Discussion Points

  • How did the dry run help prepare you for the actual welding?
  • What was the hardest part: torch control, filler timing, or foot pedal?
  • How many times did you contaminate the tungsten? What caused it each time?
  • How does the TIG experience compare to MIG welding?

Expected Outcomes

  • Students can establish and maintain a TIG arc with consistent arc length
  • Students produce at least one bead with recognizable dip-and-withdraw ripple pattern
  • Students demonstrate proper foot pedal ramp-up and crater fill technique

Assessment Rubric

Criteria Excellent (4) Proficient (3) Developing (2) Beginning (1)
Arc Control Consistent arc length, stable puddle Mostly stable with occasional fluctuation Frequent arc instability Cannot maintain arc
Filler Technique Even ripple pattern, consistent dipping Recognizable pattern with minor irregularity Inconsistent dipping, uneven bead Cannot coordinate filler addition
Foot Pedal Smooth ramp-up, steady hold, proper crater fill Good control with minor variations Inconsistent pedal control Cannot coordinate pedal with torch
Tungsten Care No contamination, or immediate recognition and correction 1-2 contaminations with proper correction Multiple contaminations Welds with contaminated tungsten

Safety Considerations

  • TIG welding produces intense UV even at low amperage — full coverage clothing required
  • TIG gloves are thinner than MIG gloves — avoid touching hot metal directly
  • Hot filler rod tip after dipping — lay it on a fire-resistant surface, not your lap
  • Argon is heavier than air — ensure adequate ventilation at floor level in enclosed booths
  • Tungsten grinding: wear safety glasses and dust mask, use only the dedicated wheel
  • Post-flow: keep the torch over the weld for the full post-flow duration (10+ seconds)

Last Updated: 2026-03-19