Why these three micro-skills control weld appearance
TIG weld appearance is largely the visible record of three things you do every moment: how long the arc is, what angle the torch points, and how fast you travel. Each one changes heat concentration and shielding coverage. Practice them as separate micro-skills first, then combine them.
| Micro-skill | What you control | What you will see when it’s right |
|---|---|---|
| Consistent arc length | Distance from tungsten tip to work | Stable puddle size, even bead width, predictable ripples |
| Steady torch angle | Lead angle and side-to-side tilt | Even edge wetting on both sides, centered bead, clean toes |
| Controlled travel speed | How fast the puddle moves | Uniform bead profile, consistent reinforcement, no undercut |
Micro-skill 1: Establishing a consistent arc length
Concept: arc length is your “focus knob”
Arc length is the gap between the tungsten tip and the work. Shorter arc length concentrates heat and tightens the arc column; longer arc length spreads heat, increases the chance of wandering, and makes shielding less effective at the puddle edges. For beginners, the goal is not “as short as possible,” but “short and repeatable.”
Practical target and body mechanics
- Target gap: keep the tip close enough that the arc looks tight and stable, but not so close that you risk touching. Many beginners use a “matchbook-thickness” mental reference; the exact gap varies with setup, but consistency is the priority.
- Lock your hand: rest the side of your hand or pinky on the table/work (or use a steadying prop) so the torch height is controlled by your wrist, not your shoulder.
- Move from the forearm: glide your hand support along as you travel so the torch-to-work distance stays constant.
Drill: arc-length-only practice (no filler)
Goal: keep puddle size constant for a full bead length without adding filler.
- Set up a straight practice line on the plate with a marker or scribe.
- Start the arc and form a small puddle.
- Travel along the line while watching the puddle diameter. Adjust torch height only enough to keep the puddle the same size.
- Stop, let cool, and inspect bead width and color consistency.
Self-check: if the bead width grows and shrinks, your arc length is changing (or your travel speed is inconsistent). Fix one variable at a time: first arc length, then speed.
Visual cues for correct arc length
- Puddle size: stays nearly constant as you move; it should not “balloon” when you pause or “shrink” when you advance.
- Edge wetting: the molten edges flow smoothly into the base metal without leaving a sharp ridge at the toes.
- Bead profile: even width and consistent reinforcement; ripples look evenly spaced when your speed is also steady.
Arc starts and how to avoid tungsten contact
High-frequency (HF) start: best for avoiding contamination
HF start initiates the arc without touching the tungsten to the work. Your job is to hold a stable starting gap and avoid “diving” the tungsten as the arc lights.
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- Position: hover at your target arc length, torch steady, centered where you want the bead to begin.
- Start: initiate the arc and wait a moment for a small puddle to form.
- Move: begin travel only after the puddle is established; starting to move too early often causes a skinny, inconsistent first inch.
Lift start: controlled contact, then lift cleanly
Lift start uses a brief touch to initiate the arc, then you lift to establish arc length. The risk is dragging or sticking the tungsten, which contaminates it and can leave a dirty start.
- Touch lightly: place the tungsten tip gently on the start point without pressure.
- Initiate: trigger the start, then lift straight up a small amount to your target arc length.
- Hold: pause to establish the puddle before moving.
Key habit: lift vertically, not diagonally. A diagonal lift can scratch the tungsten and smear metal onto it.
How to avoid tungsten contact during the weld
- Don’t chase the puddle: if the puddle grows, reduce dwell or increase travel speed rather than lowering the torch into it.
- Keep the torch hand anchored: most tungsten dips happen during repositioning. Re-anchor before continuing.
- Separate filler and tungsten paths: if you add filler, feed it into the leading edge of the puddle while keeping the tungsten centered and slightly ahead. If the filler bumps the tungsten, stop and correct before continuing.
Micro-skill 2: Maintaining a steady torch angle
Concept: angle controls heat direction and shielding coverage
Torch angle has two parts: lead angle (tilting in the direction of travel) and side tilt (leaning left/right). A consistent angle keeps the arc centered and the shielding gas blanket symmetrical over the puddle.
Practical targets
- Lead angle: use a modest forward tilt. Too much lead angle stretches the arc and can expose the puddle to air at the trailing edge.
- Side tilt: keep the torch upright side-to-side so both edges wet evenly. Side tilt often shows up as one toe washing out while the other stays tall.
Drill: angle-only practice (fixed arc length)
Goal: keep bead centered with equal wetting on both sides.
- Brace your hand so arc length is stable.
- Run a short bead while focusing only on keeping the torch angle constant (imagine the torch riding on invisible rails).
- Inspect the bead toes: they should look similar on both sides.
Self-check: if one side shows undercut or a sharper toe, reduce side tilt and re-center the arc.
Visual cues for correct torch angle
- Edge wetting symmetry: both sides of the puddle “wet” equally; the puddle should look centered under the tungsten.
- Bead alignment: bead follows your intended line without drifting.
- Surface color consistency: uneven angle can disturb shielding and cause localized discoloration near one edge.
Micro-skill 3: Controlling travel speed
Concept: speed sets bead width and reinforcement
With amperage held steady, travel speed determines how much heat is delivered per unit length. Too slow overheats the joint (wide bead, undercut risk, oxidation risk). Too fast starves the puddle (narrow ropey bead, lack of fusion risk).
Drill: speed control using puddle size as the metronome
- Start and establish a puddle of your chosen size.
- Move forward just fast enough that the puddle stays the same diameter.
- If the puddle grows, increase speed slightly; if it shrinks and looks “tight,” slow down slightly.
Ripple spacing cue: even ripples usually indicate steady speed (assuming arc length and angle are steady). If ripples bunch up, you slowed down; if they stretch out, you sped up.
Bead profile cues tied to speed
- Too slow: bead gets wider, flatter, and may show undercut at the toes.
- Too fast: bead becomes narrow and tall (ropey), with poor tie-in at the edges.
Putting the micro-skills together: a simple practice sequence
- Run 3 beads with no filler focusing only on arc length consistency.
- Run 3 beads with no filler focusing only on torch angle symmetry (keep arc length intentionally unchanged).
- Run 3 beads with no filler focusing only on travel speed (use puddle size to pace yourself).
- Run 3 beads combining all three and evaluate: bead width, toe wetting, and ripple uniformity.
Troubleshooting matrix: defects linked to arc length and angle
| Symptom/defect | Likely cause (arc length/angle/speed) | What you’ll notice while welding | Correction (single-variable first) |
|---|---|---|---|
| Wide bead | Arc too long; travel too slow; excessive lead angle | Puddle grows and feels hard to “contain” | Shorten arc slightly; increase travel speed; reduce lead angle to a modest tilt |
| Undercut at toes | Arc too long; too much heat at edges from angle; travel too slow | Edges look like they’re washing away; toe line becomes sharp | Shorten arc; re-center torch (remove side tilt); speed up slightly to reduce dwell |
| Lack of fusion (cold lap/poor tie-in) | Travel too fast; arc too long (diffuse heat); torch angle pushing heat away from edge | Puddle looks small and “skates” on top; edges don’t melt in | Slow down slightly; shorten arc; adjust angle so arc is centered on the joint/edge |
| Oxidation/discoloration on bead surface | Arc too long; excessive lead angle exposing trailing puddle; inconsistent torch angle causing shielding gaps | Color changes appear behind the puddle; surface looks dull/rough | Shorten arc; reduce lead angle; keep torch more upright and steady to maintain coverage |
| Tungsten dipping/contamination | Arc too short for your control level; unstable hand support; torch height changes during repositioning; filler contacting tungsten | Arc becomes erratic; tungsten tip may ball or spit; puddle may show dark specks | Regrind/replace tungsten as needed; re-establish a slightly longer but consistent arc; improve bracing and move the support smoothly; keep filler path away from tungsten |
Fast diagnostic: what to watch in the moment
- If puddle size is changing: fix arc length first, then speed.
- If one edge wets and the other doesn’t: fix side tilt (torch not centered).
- If the bead is consistent but too wide or too narrow: adjust travel speed in small increments while holding arc length constant.
- If starts look dirty or inconsistent: refine your start method timing (hold steady gap, establish puddle, then move) and avoid any tungsten contact.
