How to Use Pulse Settings for Better TIG Beads

What TIG Pulse Is and Why It Improves Bead Quality

TIG pulse is a feature that automatically alternates the welding current between a higher “peak” amperage and a lower “background” amperage at a set rhythm. By cycling the heat into the puddle and then letting it cool slightly, pulse helps you control heat input, narrow the heat-affected zone, and reduce distortion—especially on thin-gauge metals. The pulsing action also creates a natural timing cue that improves filler placement and promotes a uniform “stacked dimes” appearance. In short, pulse can make your beads cleaner, flatter, and more consistent while protecting the base metal from overheating.

Beyond looks, pulse is valuable for metallurgy and fit-up. On stainless steel, lowering average heat input limits oxidation, so post-weld color stays closer to straw rather than blue or gray. On thin aluminum, pulsing can prevent collapse at the joint by giving the puddle brief moments to solidify. Out-of-position welding also benefits because the puddle is less prone to sag, and the timing rhythm simplifies filler addition and travel.

Know Your Pulse Controls: Frequency, Peak/Background Amperage, and Duty Cycle

Most inverters offer three primary pulse controls: frequency (also shown as pulses per second or PPS/Hz), peak amperage and background amperage (sometimes set as a percentage of peak), and duty cycle (the percent of time spent at peak during each pulse). Frequency dictates how fast the current alternates; low frequencies provide a manual “metronome,” while high frequencies can tighten the arc and reduce overall heat input. Peak/background define how hot the puddle gets versus how much it cools, and duty cycle changes how long the arc dwells at peak for fusion. Some machines add pulse shape (square, triangular, sine), which affects how abruptly current changes and how “soft” or “crisp” the puddle feels.

As a practical rule of thumb, start with a background amperage around 30–50% of peak and a duty cycle near 30–50%. At low PPS (0.8–2 Hz), the pulse becomes an audible and visual cue: dip filler on the peak, move during background. At higher PPS (30–200+ Hz), the effect is less about timing and more about lowering average heat and tightening the arc, which is useful for very thin sheet or delicate joints. For most manual work, 1–2 Hz is a comfortable rhythm, while advanced users may prefer 30–60 Hz to stabilize a small puddle without an obvious “beat.”

Baseline Setup: Dialing In Pulse on DC for Steel and Stainless

Begin by determining your peak current based on thickness and joint type. A quick ballpark for carbon and stainless steel is 1 amp per 0.001 inch of thickness, then adjust for joint efficiency, fit-up, and position. Set background to 30–40% of peak to keep the puddle alive without overheating the joint. Choose a duty cycle around 35–45% so the puddle gets enough energy for fusion on the peak but has time to firm up on background. For a manual rhythm and “dime” spacing, start at 1–1.5 Hz; stabilize travel and filler timing before you tweak fine details.

A quick-start recipe

• Electrode: 2% lanthanated, sharpened to a point with a small flat; diameter 1/16 in (1.6 mm) for thin work.
• Shielding gas: Argon 100%, 12–20 CFH with a gas lens and #8–#12 cup as needed for coverage.
• Peak current: Approx. material thickness in thousandths (e.g., 0.060 in ≈ 60 A), then refine by test coupons.
• Background: 35–40% of peak.
• Duty cycle: 35–45% on-time at peak.
• Frequency: 1–1.5 Hz for manual timing; 30–60 Hz for tighter puddles on thin sheet.

Fine-tuning by material thickness

On 0.040–0.063 in stainless butt joints, keep background near 35% and duty cycle around 35–40% to limit color and distortion. If the ripples look too tall or the puddle feels sluggish, raise duty cycle slightly or increase peak by 5–10 amps. For 0.090–0.125 in fillets, increase duty cycle toward 45–50% to improve wash-in at the toes; if heat builds too much, bump frequency from 1 Hz to 1.5–2 Hz or raise background so the puddle does not chill excessively between peaks. Always keep arc length tight—about one tungsten diameter—to focus energy where you need it.

AC TIG and Aluminum: Using Pulse with Cleaning Action

On aluminum, pulse interacts with AC balance and AC frequency. You still set peak/background, duty cycle, and PPS, but you also need enough cleaning (electrode positive time) to break oxide and enough AC frequency to stabilize the arc. On thin sheet or heat-sensitive edges, 1–2 Hz with 40–50% background and 35–45% duty cycle creates a steady rhythm for dabbing filler at the peak and gives the puddle a chance to firm up on the background. Too much PPS on AC can feel “buzzy” and may fight puddle wetting, so keep manual pulse rates low unless you are using high-frequency micro pulse for specialized thin work.

• AC balance: Start 70–75% EN (cleaning at 25–30% EP). Increase EP only as needed to remove oxide; more EP equals more heat on the tungsten and the work surface.
• AC frequency: 80–120 Hz for crisp arc focus on fillets; lower toward 60–80 Hz for broader puddles on butt joints.
• Pulse frequency: 1–1.5 Hz for rhythm and heat control; 20–50 Hz only for very thin aluminum where micro pulse stabilizes a tiny puddle.

If the puddle looks “frosty” or resists wetting, add a touch more EP or reduce PPS to let the puddle fully form on peak. If edges are melting away, decrease duty cycle, raise background slightly, or slow travel and add filler earlier in the peak. Keep your tungsten tip clean and your AC balance under control to avoid excessive cleaning etch alongside the bead.

Torch Technique and Filler Timing: Making the Pulse Work for You

Pulse is most effective when your torch, arc length, and filler rhythm are consistent. Keep the arc length tight—roughly 1–1.5 times tungsten diameter—so peak energy goes into the joint and not into the surrounding plate. Travel smoothly during background and pause slightly at peak for fusion and filler. If you are chasing “stacked dimes,” the visual spacing of ripples corresponds to your travel distance per pulse; match your motion to the beat and keep filler size consistent. A gas lens and adequate cup size improve shielding around the puddle, which is especially important at the cooler background moments when oxidation can creep in.

Dab-on-peak rhythm

• Listen for the pulse and watch the puddle swell on peak; dab filler at the leading edge as it brightens.
• During background, advance the torch slightly while maintaining a tight arc length.
• Repeat: advance, peak/dab, background/advance. Keep your hand position steady and feed filler smoothly.

Foot pedal vs. torch switch

You can run pulse with a torch switch (locked current) or a foot pedal. With a switch, the machine controls the rhythm entirely—great for training your timing. With a pedal, most inverters scale both peak and background together as you modulate the pedal; stay steady to keep ripple spacing uniform, and make only small pedal changes for start, tie-ins, and crater fill. If your machine has slope controls, use a short downslope and maintain filler addition at the end to avoid a crater crack.

Practical Pulse Recipes by Material and Thickness

Use these starting points as baselines; verify on scrap coupons and adjust according to joint type, fit-up, position, and your machine’s behavior. Remember that every setting influences average heat input: increasing duty cycle or peak raises heat; increasing background raises heat more subtly; raising PPS reduces ripple spacing and can slightly lower average heat if duty cycle and amplitudes stay constant. Keep gas coverage generous on stainless to preserve color, and avoid long arc lengths that add heat and widen the bead.

• 0.035–0.040 in (0.9–1.0 mm) stainless butt, DCEN:
  • Peak 35–45 A; background 35–40% of peak; duty cycle 35–40%; 1–1.2 Hz.
  • 1/16 in ER308L filler; #10 cup with gas lens; 15–20 CFH argon; tight arc.
  • If color drifts blue, reduce duty cycle 5%, shorten arc, or increase travel slightly.
• 0.063 in (1.6 mm) stainless outside corner, DCEN:
  • Peak 55–65 A; background 35%; duty cycle 40–45%; 1.2–1.5 Hz.
  • Add filler sparingly at each peak to keep a crisp edge; back purge if inside is critical.
• 0.090–0.125 in (2.3–3.2 mm) mild steel fillet, DCEN:
  • Peak 90–130 A; background 40–45%; duty cycle 45–50%; 1–1.5 Hz.
  • Use a slight torch weave only if needed for toe fusion; otherwise let peak dwell do the work.
• 0.050–0.063 in (1.3–1.6 mm) aluminum butt, AC:
  • Peak 55–75 A; background 40–50%; duty cycle 35–45%; 1–1.3 Hz.
  • AC balance ~72–75% EN; AC frequency 90–110 Hz; dab 4043 filler right as peak brightens.
• Micro sheet 0.020–0.030 in (0.5–0.8 mm) stainless lap, DCEN:
  • Peak 18–30 A; background 30–35%; duty cycle 30–40%; 60–120 Hz.
  • High PPS stabilizes a tiny puddle; avoid obvious dabs and feed micro filler continuously.

Troubleshooting and Fine Adjustments for Consistent Pulse Beads

Reading the puddle and the ripple profile tells you how to adjust. Tall, spaced-out ripples with underfill suggest too little time at peak or insufficient heat—raise duty cycle 5% or bump peak 5–10 A. If the bead washes wide and sides overheat, reduce duty cycle or peak, or increase PPS from 1 to 1.5–2 Hz to tighten timing. A cold-looking root on butt joints may mean the background is set too low for the joint to stay fluid—raise background to 40–45% so the puddle doesn’t die between peaks. Arc wander or sooty edges point to poor gas coverage; switch to a gas lens, increase cup size, or correct torch angle.

• Ripples uneven or spacing inconsistent:
  • Stabilize hand position; lock your wrist and move from the shoulder.
  • Use a pedal more steadily or switch to a torch switch to let the machine keep time.
  • Set PPS to a tempo you can comfortably match—often 1–1.2 Hz for beginners.
• Lack of fusion at the toes on fillets:
  • Increase duty cycle or peak slightly; reduce travel speed on peak.
  • Shorten arc length to focus heat at the joint root.
• Excessive discoloration on stainless:
  • Lower average heat (reduce duty cycle/peak), increase argon flow within range, use trailing shield if necessary.
  • Back purge tubes and enclosed joints to protect the root from oxidation.
• Burn-through on thin edges:
  • Drop duty cycle 5–10%, raise background to 40–45% to smooth heat delivery.
  • Add filler earlier in the peak and decrease arc length; consider copper chill bars.
• Tungsten contamination:
  • Grind longitudinally and add a slight flat on the tip; keep arc tight to prevent spitting.
  • Reduce EP on AC if the tungsten is balling excessively; ensure adequate gas flow.

Essential Gear Choices That Enhance Pulse Results

While pulse settings shape heat input, your setup determines how reliably those settings translate to the puddle. A gas lens collet body with a larger cup (#8–#12) smooths gas flow, raises shielding coverage, and makes background phases cleaner. Choose electrode size for the current range; 1/16 in works well for many thin-to-medium tasks, but step up to 3/32 in for higher peaks to avoid tip erosion. Match filler diameter to puddle size; too large a rod will freeze the puddle between peaks, while too small can underfill. Keep workpieces clean and tight-fitting so the pulse can do its job without chasing contaminants or gaps.

Good foot control and cord management also matter. A stable rest for your torch hand (a prop or a dedicated rest) reduces shake and helps you hit the same distance per pulse. If you weld stainless or titanium frequently, add purge kits and trailing shields to your toolkit; pulse reduces heat tint, but shielding is what preserves metal quality. Finally, log your successful settings; noting PPS, duty cycle, background, and travel speed by material and joint type builds a personal database you can return to for repeatable results.