English
Views: 0 Author: Site Editor Publish Time: 2025-08-18 Origin: Site
What Is TIG Welding Aluminum?TIG means gas tungsten arc welding. We guide a tungsten electrode. It does not melt. We feed a separate filler rod by hand. Pure argon shields the arc and the puddle. It feels like drawing lines using light and metal. Many teams pick TIG for clean beads on industrial aluminum profile frames or custom brackets from extruded aluminum.
Non-consumable tungsten electrode
Separate filler wire
Inert shielding gas, usually 100 percent argon
Foot pedal or fingertip control for heat
Short arc length for a tight, stable puddle
A quick flow
Clean and degrease the joint and the filler.
Strike arc using high frequency start.
Form a shiny puddle.
Dab filler at the leading edge.
Taper off, fill the crater, hold post-flow.
We often demo on small jigs built from T slot aluminum profiles, then move to real parts from aluminum extrusion stock.
Aluminum grows a tough oxide skin. It melts far above the base metal. AC solves the puzzle.
Electrode positive, called EP, scrubs oxide.
Electrode negative, called EN, drives heat into the base metal.
Simple map
| AC aspect | What it does | Visual cue | When to adjust |
|---|---|---|---|
| EP time | Cleans oxide | White etch band near bead | Soot on bead, widen EP |
| EN time | Penetration | Deeper fusion line | Oxide islands, narrow EP |
| AC frequency | Arc shape | Higher tightens the arc | Outside corners, fillets |
We tune these dials for thin sheet, cast parts, or thick plate. It keeps beads bright and consistent.
Both weld aluminum. Each shines in a different lane. We pick based on finish, speed, and part style. A robot cell frame in a lab might need TIG for clean joints around aluminum angle gussets. A long run on plate might call for MIG.
| Factor | TIG welding aluminum | MIG on aluminum |
|---|---|---|
| Bead appearance | Smooth, tight ripple | Wider, more build |
| Control on thin stock | High, precise heat | Tricky on very thin |
| Speed on long seams | Slower | Faster |
| Setup | More parameters | Simpler once dialed |
| Best use | Workbenches, fixtures, show parts | Brackets, trays, long seams |
Yes, in rare cases. It needs skill and strict prep. DCEN plus helium can push heat into very thick sections. Big drawbacks remain, since oxide removal does not happen like AC.
Surface must stay ultra clean.
Arc start feels sluggish on cold parts.
Oxide can streak across the puddle.
Black soot shows up fast if gas coverage drops.
Quick checklist for DC experiments
Helium or Ar-He mix for heat density
Larger tungsten, tight arc, gas lens
Short runs, constant cleaning between passes
Most beginners stick to AC. We do the same when building fixtures for machine guarding near aluminum tube frames from our shop inventory. It keeps results repeatable and inspection friendly.
We stay safe first. It pays off every single bead. Keep eyes, lungs, skin, and crew in mind. Simple habits prevent big problems.
The arc throws intense UV and IR. Eyes and skin feel it fast. We pick a helmet shade that keeps the puddle clear and glare low.
Helmet shade quick map
| Amperage on AC | Suggested shade | What you see | Notes |
|---|---|---|---|
| 40–80 A | 9–10 | Clear puddle, mild glare | Good for thin sheet and tacks |
| 80–150 A | 10–11 | Crisp edges, ripple visible | Daily work range |
| 150–200 A | 11–12 | Bright but controlled | Plate and fillets |
| 200–250 A | 12–13 | Manageable brightness | Heavy sections |
Wear safety glasses under the hood. It protects eyes during brushing and grinding.
Cover skin. Jacket, neck, and hands. No gaps. UV burns feel sneaky.
Check lens for pits or haze. If it blurs the puddle, we swap it out.
TIG on aluminum can create ozone and NOx near the arc. Lungs hate it. We pull fumes away while the argon shield stays calm.
Use local extraction. A fume arm or hood close to the plume. Not so close it disturbs the gas.
Aim for a gentle draw. If the arc flickers or the puddle soots up, airflow runs too hard.
Try a simple test. Hold a small smoke source near the joint. It should drift into the hood, not swirl over the cup.
Keep shop air moving. Doors open, fans set for smooth flow. No direct blast at the torch.
Airflow do and don’t
Do position the hood slightly above and to the side of the puddle.
Don’t point a fan straight at the cup. It strips the shield.
Do brush and wipe parts clean. Less smoke, fewer irritants.
Argon feels safe. It displaces oxygen, it has no smell, it gives no warning. Confined spaces turn risky fast.
Avoid pits, tanks, tight rooms. If we must enter, use an oxygen monitor.
Keep cylinders upright and chained. Caps on during transport.
Check for leaks using soapy water. Hissing means we close the valve and fix it.
Purge lines only as needed. No long free flows into the room.
Cylinder handling mini checklist
Secure at two points
Cap on during move
Valve closed when idle
Regulator intact, gauges readable
Fire loves grinders, spatter, and dust. We set the bay for safe work before we strike an arc.
Fire safety
Clear combustibles from the zone.
Keep a rated extinguisher close. Everyone knows it and can grab it.
Assign a fire watch for spark-heavy jobs.
Cool the part on a nonflammable surface. No oily rags nearby.
Cable routing
Lay leads flat, away from sharp edges.
No loops around the body. No knots under boots.
Tape or cover passages so feet do not snag.
Ground clamp near the joint. Short return path helps stability.
PPE checklist
| Item | Use | Ready |
|---|---|---|
| Auto-darkening helmet | UV/IR and spatter | ☐ |
| Safety glasses | Brush and grind | ☐ |
| Welding jacket and sleeves | Skin coverage | ☐ |
| TIG gloves | Dexterity and heat | ☐ |
| Leather boots | Foot protection | ☐ |
| Respirator (when needed) | Ozone/particulates | ☐ |
| Hearing protection | Grinding and cutting | ☐ |
Before we weld
Parts degreased and brushed. Clean bench.
Extraction on. Fan set for smooth flow.
Cylinder secure. Regulator set. No leaks.
PPE on. Extinguisher in reach. Ground close to the weld.
We keep this simple and practical. Grab the right kit, dial a few basics, then strike clean arcs.
AC mode for aluminum. Oxide breaks under EP, metal heats under EN.
HF start for clean arc starts. No tungsten taps.
Amperage rule: about 1 amp per 0.001 in thickness. Bump up for large heat sinks.
AC balance starter: 65–75 percent EN. More EN for penetration, more EP for cleaning.
AC frequency starter: 100–120 Hz for corners and fillets, 60–80 Hz for a wider puddle.
Independent EN/EP amperage when the power source allows. Higher EN than EP for deeper fusion and cooler tungsten.
Post-flow gas: keep shielding over the bead and tungsten for a few seconds.
Feature quick map
| Control | Why it matters | Starter move |
|---|---|---|
| AC mode | Oxide removal plus fusion | Always on for aluminum |
| AC balance | Cleans vs penetrates | 70% EN, tweak by etch band |
| AC frequency | Arc width vs focus | 100–120 Hz for tight work |
| EN/EP split | More fusion, less tungsten heat | EN above EP on advanced inverters |
| Post-flow | Protects bead and tungsten | 5–10 s, longer on big cups |
Gas lens gives smoother flow and broader coverage. Handy near edges and corners.
Standard cup works fine on open joints and practice coupons.
Cup size guide:
#6–#7 for light work up to ~120 A
#8–#10 for 120–200 A or tight access
Larger cups for outside corners, long stickout, heavy sections
Collet body: standard for general use, gas lens body for calmer shielding.
Back cap: short cap for tight spaces, long cap for convenience at the bench.
Cup chooser
| Joint style | Thickness | Cup | Gas flow (L/min) |
|---|---|---|---|
| Butt, thin sheet | ≤ 1.6 mm | #6–#7 | 7–10 |
| Outside corner | 2–6 mm | #8–#10 | 9–14 |
| Fillet in a frame | 3–10 mm | #8–#10 | 10–14 |
Pick 2% lanthanated for a strong all-round choice. Ceriated or zirconiated also run well.
Pure tungsten and big spherical balls get a pass on modern inverters. Arc wanders, heat loads the tip, cleaning band grows too wide.
Shape the tip to a truncated cone or a slight dome. Keep it short and tidy.
Tungsten size guide
| Diameter | Current range | Notes |
|---|---|---|
| 1.6 mm (1/16 in) | ~40–130 A | Thin sheet, small cups |
| 2.4 mm (3/32 in) | ~90–200 A | Daily workhorse |
| 3.2 mm (1/8 in) | ~150–300 A | Thick plate, long runs |
ER4043: smooth puddle, easy feeding, good crack resistance on many jobs.
ER5356: higher strength, better for structural parts and brackets, different color after anodize.
Diameters: 1.6 mm (1/16 in) for thin parts, 2.4 mm (3/32 in) for general plate, 3.2 mm (1/8 in) for heavy sections.
Filler chooser
| Filler | Strength | Crack behavior | Anodize color | Best fit |
|---|---|---|---|---|
| ER4043 | Medium | Friendly | Closer match | Castings, general fab |
| ER5356 | Higher | Stiffer | Darker shift | Frames, brackets, marine |
When to change wire size
Upsize for thick plate, big heat sink parts, long beads.
Downsize for thin skins, small corners, short stitch runs.
100 percent argon covers most work. Clean starts, stable arc, bright bead.
Argon–helium blends help on very thick aluminum. Hotter arc, deeper bite. Start near 75/25 Ar/He then tune.
Keep gas lines leak free. Smooth flow beats high flow.
Gas picker
| Part size | Gas | Why |
|---|---|---|
| ≤ 6 mm sheet | 100% Ar | Easy starts, clean ripple |
| 6–12 mm plate | 100% Ar | Add amps or preheat as needed |
| ≥ 12 mm plate | Ar–He blend | Extra heat density |
Stainless brush kept only for aluminum. No cross-contamination.
Acetone for degreasing before brushing.
Lint-free wipes for a final pass.
Clamps and fixtures for steady joints and repeat setups.
Copper chill bars or backing for thin edges and heat control.
Layout tools: scribe, square, deburring tools, fresh abrasives.
Bench checklist
Parts degreased, edges deburred
Brush ready, labeled for aluminum only
Cups and gas lens sorted by size
Fresh tungsten prepped and stored dry
Filler cut clean, ends wiped
Clamps, squares, copper backing on the table
We dial the machine first. It saves time, it saves rework. Simple dials guide clean beads on AC TIG aluminum.
Start near 1 amp per 0.001 in of base-metal thickness. Then nudge for joint style and position.
Starter table
| Thickness | Decimal | Amperage start | Notes |
|---|---|---|---|
| 1/16 in | 0.063 in | ~60–80 A | Thin sheet, short arc |
| 3/32 in | 0.094 in | ~90–120 A | Common brackets |
| 1/8 in | 0.125 in | ~120–160 A | Workhorse range |
| 3/16 in | 0.188 in | ~180–220 A | Add tacks, steady travel |
| 1/4 in | 0.250 in | ~240–300 A | Preheat or Ar–He helps |
Tips
Flat position runs cooler. Vertical or overhead needs a touch less heat.
Copper backing lowers burn-through risk on thin edges.
Long beads pull heat in. We pulse the pedal or pause between sections.
AC splits time between EP and EN. The pale etch band tells the story.
What the bead says
| Balance issue | What we see | What we do |
|---|---|---|
| Too much EP | Soot on toes, hot tungsten, wide white band | Shift toward more EN |
| Too little EP | Oxide islands, dull edges, poor wet-in | Add EP until islands vanish |
| About right | Narrow even etch, bright bead, stable tip | Leave it, focus on arc length |
Starter move
Set ~70 percent EN. Watch the etch. Adjust a few points at a time.
If the tip glows early, EP runs high. If oxides skate across the puddle, EP runs low.
Frequency changes arc shape and steering.
Quick choices
| Frequency | Arc behavior | When we use it |
|---|---|---|
| 60–80 Hz | Wider, softer arc | Flat plate, open butt joints |
| 100–150 Hz | Tighter, more directional | Fillets, outside corners |
| 200+ Hz | Very tight, crisp edges | Thin corners, small joints, precise heat |
Higher numbers focus the arc. Lower numbers spread heat for wider wet-in.
Some inverters split current on each half cycle. We use it for deeper fusion and cooler tungsten.
Boost EN above EP. It pushes heat into the work.
Keep EP modest. It cleans oxide, it stops tip overheat.
Small changes go far. We track the etch band and puddle fluidity.
Shielding matters as much as amps. Calm gas, calm puddle.
By cup size
| Cup | Flow (L/min) | Notes |
|---|---|---|
| #6–#7 | 7–10 | Thin sheet, short stickout |
| #8–#10 | 9–14 | Daily work, corners, fillets |
| Big cups | 12–18 | Long stickout, outside corners |
Post-flow keeps the tungsten and bead under argon while they cool.
Post-flow time: ~5–10 s on small cups, longer on big tungsten or hot runs.
Hiss stops too soon, tips go gray. We add seconds until tips stay shiny.
Clean starts, clean stops. We let the machine help us.
HF start or HF continuous for arc stability near edges.
Pre-flow: 0.3–0.7 s so gas arrives before arc.
Upslope: short ramp-in for smooth puddle formation.
Downslope: gentle ramp-out, then crater fill using a small dab at the end.
Hold the cup for post-flow. It protects the cooling bead and the hot tip.
Control map
| Control | Purpose | Starter value |
|---|---|---|
| Pre-flow | Flood the cup before arc | 0.5 s |
| Upslope | Prevent cold starts | 0.3–0.7 s |
| Downslope | Prevent crater cracks | 0.7–1.5 s |
| Post-flow | Shield tungsten and bead | 5–10 s |
Mini checklist
Amps set by thickness, then trimmed for joint and position
Balance tuned by the etch band, not guesswork
Frequency matched to joint geometry
EN above EP on advanced machines for fusion and tip life
Gas flow steady, post-flow long enough for a bright tip
We slow down, then make each move count. Short arc, clean dabs, calm hands. It feels like writing your name in light.
Ground placement
Clamp close to the joint. Paint and anodize removed under the clamp.
Solid contact. No paint. No oil.
Torch build
Gas lens for smooth shielding on edges and corners.
Standard cup for open joints or practice runs.
Cup numbers: #6-#7 for thin sheet, #8-#10 for most jobs, larger for long stickout.
Tungsten: 1/16 in to 3/32 in for common work. Tip shaped to a truncated cone or a slight dome.
Quick torch guide
| Part style | Cup | Tungsten dia | Stickout | Note |
|---|---|---|---|---|
| Thin sheet butt | #6-#7 | 1/16 in | Short | Easy starts, small puddle |
| Fillet or corner | #8-#10 | 3/32 in | Short-medium | Tighter arc helps toes wet in |
| Outside corner, long reach | #10+ gas lens | 3/32 in | Longer | Extra flow keeps shield stable |
Two hands locked in. One on torch, one on filler, wrists braced on the table or part.
Torch push angle near 10-15 degrees. Small lean, steady wrist.
Set your line of travel before arc start. Eyes on the next 10 mm, not the tip only.
Keep arc length near 1 to 1.5 x tungsten diameter.
Short arc tightens heat, lowers porosity, brightens the bead.
If the arc hisses or wanders, move closer and reset the hand brace.
Arc cues
Too long: grainy puddle, sooty toes, lazy tie-in.
Just right: crisp puddle edge, quiet sizzle, narrow etch band.
Start the arc, wait for a shiny, liquid lens. Edges look bright and mobile.
No rush on the first dab. Let base metal open.
If it looks dull or sluggish, add a breath of pedal or bump AC balance toward more cleaning on the machine.
Visual checklist
Shiny pool center
Clean halo at the edge
No pepper in the surface
Feed at the leading edge of the puddle. Keep the wire inside the gas envelope.
Short, frequent dabs. Small rhythm controls heat and bead width.
Pull back the wire before travel resumes. No wire dragging in open air.
Filler do and dont
Do trim and wipe the end before a run.
Do keep the hand low and steady.
Dont dip the tungsten. If it happens, stop, regrind, reset.
Ramp-in: ease to heat, let the puddle open.
Steady travel: hold a mid-pedal point, then modulate during each dab.
Crater fill: slow down at the end, add a small dab, then ramp-out to zero.
Hold the cup in place for post-flow. The puddle and tungsten cool under argon.
Pedal timeline
| Phase | Pedal move | Purpose |
|---|---|---|
| Start | Smooth ramp up | Form a clean puddle |
| Run | Small pulses during dabs | Keep bead even, limit overheat |
| End | Slow ramp down | Stop crater cracks |
Use a step-and-dab cadence. Move a few millimeters, pause, dab, move again.
Count in your head. One-two, one-two.
Ripple spacing matches your count. Even count, even texture.
If the puddle grows too wide, shorten the arc, speed the travel, add smaller dabs.
We pick filler before we strike an arc. It shapes strength, look, and post-finish results. Simple rules help, then tests on scrap confirm the choice.
Flows easy. Wetting feels calm, bead lays flat.
Good crack resistance on many jobs, including cast repairs.
Likes heat control on thin skins. It forgives small gaps.
Anodize turns dark gray. Color contrast shows fast on show parts.
Where we grab 4043
General fab on 6xxx extrusions
Cast aluminum housings and brackets
Cosmetic joints that need smooth ripples before anodize or paint
Higher tensile strength. Stiffer bead under load.
Better choice for marine or bracket duty.
Feeds well in larger diameters for heavy plate.
Anodize usually closer to base color on 5xxx/6xxx parts.
Where we grab 5356
Frames, braces, and aluminum beams in fixtures
Marine hardware, ramps, machine stands
Parts that take vibration or shock
| Property | 4043 (Al-Si) | 5356 (Al-Mg) |
|---|---|---|
| Bead feel | Smooth, easy wet-in | Firmer, more build |
| Crack resistance | Strong on many alloys | Good, stiffer under flex |
| Tensile | Moderate | Higher |
| Feed in larger diameters | Moderate | Strong |
| Anodize color | Dark gray contrast | Closer match on many 5xxx/6xxx |
| Typical jobs | Cast repair, general fab | Structural frames, marine |
We keep both on the bench. It covers most work on industrial aluminum profile projects, including V Slot Aluminum Profile frames or curved rails from Curved Aluminum Profile stock.
Pick filler by base alloy first, then tune by service needs.
| Base alloy | Behavior | Go-to filler | Notes |
|---|---|---|---|
| 6061-T6 | Strong, heat-treatable | 4043 or 5356 | 4043 for smooth flow and crack resistance. 5356 for higher tensile and closer anodize color. HAZ softens after weld. |
| 5052-H32 | Non-heat-treatable, good formability | 5356 | Magnesium base pairs well. Nice for sheet enclosures and trays. |
| 3003 | Soft, very formable | 4043 | Easy puddle, clean cosmetic beads. |
| Cast aluminum (A356, similar) | Porosity risk, silicon rich | 4043 | Preheat helps. Short beads, frequent cleaning between passes. |
If a job mixes alloys, we choose the filler that protects crack risk first. Strength comes next.
| Diameter | Where it shines | Why we pick it |
|---|---|---|
| 1/16 in (1.6 mm) | Thin sheet, corners | Cooler dabs, tight control |
| 3/32 in (2.4 mm) | Daily plate work | Balanced deposit, steady rhythm |
| 1/8 in (3.2 mm) | Heavy plate, long beads | Fewer stops, stronger freeze |
We downsize for tiny corners on enclosures from 5052. We upsize for long fillets on guard frames or partitions similar to Guard Fence builds.
Different metals love different chemistries. Fusion welds across big gaps in composition form brittle layers fast. We use safe routes.
Aluminum to steel
Direct fusion: not recommended. Brittle intermetallics grow fast.
Safer path: bimetal transition strips or explosion-bonded inserts. Weld aluminum side using 4043 or 5356 per alloy, then join steel side using standard steel process.
Backup plan: mechanical fasteners, adhesive bonding, or TIG brazing on aluminum side plus steel welds nearby.
Aluminum to copper
High thermal conductivity pulls heat away. Pool goes sluggish.
Intermetallics grow brittle.
Options: mechanical joints, dedicated transition materials, or controlled TIG brazing using Al-Si filler on copper pads. Small beads, strict cleanliness, short heat cycles.
Decision matrix
| Pairing | Fusion TIG | Transition piece | Braze option | Mechanical |
|---|---|---|---|---|
| Al ↔ steel | No | Yes, preferred | Limited, niche | Yes |
| Al ↔ copper | Risky | Yes, where available | Possible on simple pads | Yes |
We test every dissimilar joint on coupons first. Short runs, fresh prep, tight gas coverage. It saves real parts from surprises.
We keep moves simple. Short arc, clean filler, calm hands. It pays off fast on real jobs like Aluminum Tube frames or light Factory Partition panels.
Hold arc length near one to one-and-a-half tungsten diameters.
Keep wire inside the shield. No feeding out in open air.
Wipe wire ends using acetone. Trim dull tips before a run.
If soot shows up, move closer, steady your brace, check gas flow.
Quick cue table
| Symptom | Likely cause | Fast fix |
|---|---|---|
| Grainy bead | Arc too long | Close the gap, shorten stickout |
| Sooty toes | Weak shielding or low EP | Increase flow a touch, add EP a few points |
| Dull, flat puddle | Dirty wire or base | Re-wipe, fresh brush pass |
Dab little, dab often. Puddle stays tight, bead stays narrow.
Aim dabs at the leading edge. No dragging.
If the pool brightens too much, add a quick dab, lift off, continue travel.
Mini drill
Run a straight line on scrap.
Count one-two, dab on two.
Keep ripple spacing even across the line.
Keep a gentle 10–15° push. Steeper angles blow the shield and pull in air.
Plant both hands. Elbows down, wrists braced on the bench or part.
For awkward corners on Custom Aluminum Extrusion parts, swap to a short back cap, bring the body in close.
Angle vs effect
| Torch angle | Gas coverage | Result | Move |
|---|---|---|---|
| 0–5° | Strong | Deep, focused | Use on fillets |
| 10–15° | Balanced | Clean toes, stable arc | Daily target |
| 20°+ | Weak | Soot, porosity risk | Reduce angle, re-brace |
Pale etch band should look narrow and even.
Too much EP → hot tungsten, wide white band, soot. Shift toward more EN.
Too little EP → oxide islands, poor wet-in. Add EP a few points.
Balance cheat card
| Look | Read | Tweak |
|---|---|---|
| Wide white fringe | Excess EP | Add EN 5–10% |
| Dark islands in toes | Low EP | Add EP 5–10% |
| Bright bead, narrow fringe | On target | Leave it, watch arc length |
Stop once the puddle turns peppery or gray.
Re-wipe, dress the tack, re-grind tungsten if it touched metal.
Swap to a fresh cup or screen if flow feels rough.
Quick reset beats a long grind after a failed pass.
Reset checklist
Base wiped and brushed
Tungsten clean, slight dome or truncated tip
Gas lens clear, O-rings seated
Filler ends bright and dry
Pro tip box for real parts
On thin tray edges or door frames, park a copper chill bar under the seam. Puddle stays small, bead looks crisp.
For long seams on racks, add short pauses every 75–100 mm. Heat drops, color stays bright.
Keep a small kit of Aluminum Profile Accessories ready: end caps, corner clamps, quick squares. Setups go faster, beads land where we planned.
We all slip sometimes. Spot the sign, make one tweak, move on. Use this list at the bench.
| Mistake | What you see | Fast fix |
|---|---|---|
| HF not set correctly | Hard starts, arc drops out | Set HF start or HF continuous, check leads, clean ground pad |
| Wrong tungsten or over-balled tip | Wandering arc, wide etch band | Swap to 2 percent lanthanated or ceriated, dress to truncated cone |
| Contaminated surfaces or filler | Pepper in puddle, dull bead | Degrease → brush → final wipe, trim and wipe filler ends |
| Arc too long | Grainy bead, soot on toes | Shorten arc to 1–1.5× tungsten diameter |
| Excessive torch angle | Porosity spikes, noisy arc | Hold 10–15° push angle, re-brace both hands |
| Over or under AC balance | Sooty bead or oxide islands | Tune by etch width, add or reduce EP in small steps |
| Insufficient gas post-flow | Gray tungsten, hazy bead tail | Extend post-flow 5–10 s, hold cup over crater |
| Too much heat, no travel | Burn-through, warping | Raise travel speed, add pauses, use copper backing |
| Wrong wire diameter | Cold lap or over-cooling | Downsize for thin sheet, upsize for heavy plate |
| Skipping crater fill | Star cracks at the end | Downslope, small final dab, hold post-flow |
A: AC cleans oxide; DC only thick plate, helium.
A: 4043: smooth, crack resistant. 5356: stronger, structural.
A: About 1A per 0.001 in. 1/16: 60-80; 1/8: 120-160; 1/4: 240-300.
A: Two percent lanthanated; 1/16-3/32 in; truncated tip.
A: Clean metal and wire; short arc; steady gas; add EP.
A: Narrow even etch good. Wide white: reduce EP. Oxides: add EP.
A: Preheat only thick jobs. 140-250 F. Interpass below 300 F.
A: Downslope, tiny final dab, hold postflow.
A: Yes for thin sheet. Lowers heat, evens ripples.
A: Cast: prefer 4043, gentle preheat, short beads, frequent cleaning.
A: Postflow 5-10 s small cups; longer on hot tungsten.
A: Stop, regrind tip, reclean, restart.
