TIG Tungsten Electrode Guide: Colour Codes, Thoriated vs Lanthanated vs Ceriated, Sharpening & Selection for Australian Welders

The tungsten electrode is the only non-consumable electrode in the welding family. Where MIG wire and stick electrodes burn into the weld puddle, the tungsten in a TIG torch stays out of the weld — it forms the arc, the puddle is formed by base metal and filler rod, and the same tungsten can produce dozens or hundreds of welds before it needs regrinding. That makes tungsten selection different from every other welding consumable decision: you're not choosing a single-use rod, you're choosing the electrode that will sit at the end of your torch through every weld in a job and define arc behaviour, weld appearance and electrode life.

This guide explains the AWS A5.12 colour-code system that identifies every tungsten type at a glance, the practitioner-validated thoriated-vs-lanthanated-vs-ceriated decision (and why most Australian workshops have migrated away from thoriated for safety reasons), point geometry and sharpening science, DC vs AC selection by material, sizing by amperage, the practitioner discipline that separates clean welds from contaminated ones, and the AIMS supply story across Bossweld and the broader Australian welding-consumable market.

Why tungsten matters in TIG welding

TIG (GTAW — Gas Tungsten Arc Welding) creates the welding arc between a tungsten electrode held in the torch and the workpiece. Argon shielding gas flows around the electrode and arc, protecting the molten puddle from atmospheric contamination. Filler rod is fed by hand if filler is needed. The tungsten is theoretically non-consumable — in practice, the tungsten erodes over time, contaminates if it touches the puddle or rod, and must be regularly resharpened and occasionally replaced.

Tungsten as a refractory metal has the highest melting point of any pure metal at 3422°C. That is the property that makes the TIG electrode possible: an arc temperature of 5500-7000°C melts the workpiece but does not vaporise the tungsten provided the electrode is correctly sized and operated. Pure tungsten alone works adequately on AC but performs poorly on DC. The fix discovered in the 1940s: blend small percentages of rare-earth or other oxides into the tungsten matrix to improve electron emission, arc stability, and tip wear characteristics.

The result is the modern tungsten electrode market — eight major types, each with a specific oxide blend tuned for a particular application, all marked with a standardised colour code that lets welders identify the right tungsten through the packaging on a busy shop floor.

The AWS A5.12 colour-code system — the welder's reference chart

AWS A5.12/A5.12M:2009 (modified from ISO 6848:2004) is the international specification that defines tungsten electrode types and the colour-band identification system used worldwide. The Australian adoption is AS/NZS 1167.5. The colour band is painted at one end of the electrode; for boxed electrodes, the colour also appears on the packaging label. The system lets a welder identify the correct tungsten without reading labels — critical when juggling multiple TIG jobs with different material requirements.

AWS Code	Colour	Oxide	%	Best for
EWP	Green	None (pure tungsten)	99.5%+ W	AC aluminium and magnesium (legacy transformer welders)
EWCe-2	Grey (Orange in older AWS)	Cerium oxide (CeO2)	2.0%	Low-amperage DC, thin-section work, orbital welding
EWLa-1.5	Gold	Lanthanum oxide (La2O3)	1.5%	Universal — DC steel/stainless + AC aluminium
EWLa-2 / WL20	Blue	Lanthanum oxide	2.0%	Universal — slightly tougher than 1.5%, modern workshop default
EWTh-2	Red	Thorium oxide (ThO2)	1.7-2.2%	Legacy DC steel/stainless — radioactive, being replaced by lanthanated
EWTh-4	Brown	Thorium oxide	3.0-4.2%	High-amperage DC — radioactive specialty
EWZr-1 / EWZr-8	White (Brown in older AWS)	Zirconium oxide (ZrO2)	0.15-0.40% / 0.7-0.9%	AC welding requiring stable balled tip
EWG (rare earth / mixed)	Purple	Unspecified rare earth blend	Varies	Manufacturer-specific specialty blends (Multi-Strike, Tri-Mix)

The colour-band system is more than a labelling convenience — it is a safety system. Mixing thoriated electrodes (radioactive) with lanthanated or ceriated in the same workshop without clear identification creates real risk. The colour code makes the type identifiable through the packaging, from across a workbench, after the original box has been thrown out.

Three practical rules from the colour-code chart:

• Green is pure tungsten — AC aluminium only. Don't use on DC steel.
• Red is thoriated — radioactive. Grinding dust contains thorium oxide. Workshop safety controls required.
• Gold (1.5%) and Blue (2%) lanthanated are the modern universal choice. Per Miller Welding and Practical Machinist consensus, 2% lanthanated typically offers the best balance between arc starting, stability and electrode longevity across DC and AC applications.

Pure tungsten (EWP / green) — the AC aluminium specialist

Pure tungsten contains no oxide additions — just 99.5%+ tungsten with trace impurities. Its single specialty is AC welding of aluminium and magnesium, primarily on older transformer-based AC TIG machines where the electrode is operated with a balled tip rather than a sharpened point.

The balled-tip mechanism: as AC alternates between electrode-positive and electrode-negative half-cycles, the electrode-positive cycle pulls electrons from the workpiece (cleaning the aluminium oxide layer) but heats the tungsten significantly. A pointed pure tungsten tip would melt and migrate. A balled tip — formed by initial high-current arc striking on copper scrap — provides a stable hemispherical surface that handles the AC heating cycle without further migration. Ball diameter approximately 1 to 1.25 times the electrode diameter.

Where pure tungsten still fits:

• Older transformer-based AC TIG welders (pre-inverter era) where square-wave AC is not available
• AC aluminium work where balled-tip arc behaviour is preferred — some welders find the broader arc cone gives better aluminium puddle control
• Magnesium welding — same balled-tip technique as aluminium

Where pure tungsten falls short: DC welding of steel and stainless. Pure tungsten has poor electron emission compared to oxide-enhanced alternatives. Arc starting is harder, arc stability is worse, and the electrode wears faster. Modern lanthanated, ceriated and thoriated alternatives outperform pure tungsten on DC by every measurable criterion.

The practitioner consensus visible across Miller Welding and WeldingWeb threads: modern AC inverter machines with square-wave AC run lanthanated or ceriated electrodes with sharpened points more successfully than pure tungsten with a ball. Pure tungsten remains in service primarily on legacy transformer machines and where workshop tradition dictates the balled-tip workflow.

Thoriated tungsten (EWTh-2 red, EWTh-4 brown) — heritage choice with safety baggage

Thoriated tungsten was the welding industry standard for DC TIG of steel and stainless from the 1950s through the early 2000s. 2% thorium oxide (EWTh-2 / red) delivers excellent arc starting at low amperage, stable arc behaviour across the working range, and long electrode life. 4% thorium (EWTh-4 / brown) is a higher-amperage specialty variant.

The catch — and it is a significant catch — is thorium's radioactivity. Thorium-232 is a naturally occurring radioactive isotope. The electrode itself emits low levels of alpha radiation that are blocked by the electrode coating and the user's gloves. The actual hazard is in the grinding dust: thorium oxide particles can be inhaled during electrode sharpening and accumulate in the lungs over years of exposure. The same dust contaminates the surfaces of the workshop tungsten grinder if it's shared with other materials.

Per AU workshop safety practice (AS/NZS 1674.2 welding safety + SafeWork Australia hazardous chemicals guidance):

• Dedicated tungsten grinder required. Bench grinder sharing tungsten with steel, aluminium or other materials cross-contaminates both directions and exposes the operator.
• Local exhaust ventilation at the grinder. Grinding dust must be captured at source, not allowed to settle on workshop surfaces.
• Respiratory protection during grinding. P2 filter respirator minimum when grinding thoriated electrodes.
• Disposal as low-level radioactive waste. Thoriated tungsten grinding residue is classed as low-level radioactive waste in many jurisdictions including Australia.

The practitioner response across Practical Machinist, Miller Welding and WeldingWeb threads has been a sustained migration to non-radioactive alternatives. 2% lanthanated (EWLa-2 / blue) and 2% ceriated (EWCe-2 / grey) deliver equivalent or better performance to thoriated on DC steel and stainless without the radioactivity hazard. Direct user quote from Miller Welding forum: "2% lanthanated typically offers the best balance between arc starting, stability, and electrode longevity."

Thoriated tungsten remains in workshops because of long-standing practitioner habit and existing inventory. It is not banned in Australia, and competent grinding practice manages the hazard adequately. But for a workshop choosing new tungsten supply today, lanthanated is the safer and equally-performing choice.

Lanthanated tungsten (EWLa-1.5 gold, EWLa-2 blue) — the modern universal

Lanthanated tungsten uses lanthanum oxide (La₂O₃) as the oxide additive. The lanthanum is a rare-earth element with excellent electron-emission characteristics, comparable to or exceeding thorium in TIG arc behaviour, and crucially non-radioactive.

Two grade variants dominate:

• EWLa-1.5 (Gold band) — 1.5% lanthanum oxide. Balanced choice for general workshop TIG across DC and AC modes. Slightly softer than EWLa-2 on high-amperage DC.
• EWLa-2 / WL20 (Blue band) — 2% lanthanum oxide. The modern universal workshop default. Better tip life at high amperage than 1.5%. Performs well on DC steel/stainless, AC aluminium (with modern square-wave inverter), and low-amperage thin-section work.

Practitioner advantages compared to thoriated (red) and ceriated (grey):

• Equal or better arc starting — particularly with HF (high-frequency) arc start systems
• Lower amperage requirement for given weld — practitioner reports of 10-20% amperage reduction vs thoriated at equivalent arc behaviour
• Longer electrode life on stainless and chrome-moly work — oxide migrates more slowly than ceriated
• Non-radioactive grinding — workshop safety obvious
• Works on AC and DC — single tungsten type stocked for both modes

The buying decision filter most workshops apply: start with 2% lanthanated (blue) as the workshop default; add specific types for specialty work. A workshop running general fabrication can run 2% lanthanated on virtually every job — DC steel, DC stainless, AC aluminium with modern inverter, and the practitioner discipline transfers directly between materials without learning new arc behaviour. The cost premium versus thoriated is modest; the safety benefit is significant.

Ceriated tungsten (EWCe-2 / grey) — low-amperage specialist

Ceriated tungsten uses 2% cerium oxide (CeO₂) as the additive. Like lanthanated, it is non-radioactive. Its specialty is low-amperage DC TIG on thin sections and orbital welding — applications where arc starting at very low amperage and a stable narrow arc cone matter more than electrode longevity at high amperage.

Where ceriated wins:

• Orbital tube welding — pharmaceutical, semiconductor, food processing tubing. Ceriated delivers consistent starts and stable arc at the very low amperages typical of this work.
• Thin-section sheet metal TIG — under 1.5 mm aluminium or stainless. The narrow arc cone gives precise puddle control.
• DC pulse TIG — pulsed-current TIG with sub-100 A peaks. Ceriated arc-restart characteristics fit pulse mode well.

Where ceriated falls short — and this is the critical practitioner warning documented across Diamond Ground Products and BakersGas industry content: at higher amperages, the cerium oxide migrates quickly from the body of the electrode to the heated tip, depleting the oxide content and nullifying the performance advantage. A ceriated electrode used at high amperage degrades quickly to behaviour equivalent to pure tungsten — poor arc starting, tip melting, electrode wear.

The practical rule from forum consensus: ceriated below 100 A; lanthanated above 100 A. The two are complementary rather than competitive. Workshops doing both thin-section orbital work and heavier-gauge fabrication often stock both.

Zirconiated tungsten (EWZr-1, EWZr-8 / white) — AC alternative to pure tungsten

Zirconiated tungsten contains a small percentage of zirconium oxide (ZrO₂) — 0.15-0.40% in EWZr-1 (brown band in older AWS) or 0.7-0.9% in EWZr-8 (white band). It is designed as an improved alternative to pure tungsten for AC aluminium welding — better arc stability, longer electrode life, less spitting at the workpiece, while still forming a stable balled tip.

Where zirconiated fits:

• AC aluminium welding on transformer or older AC TIG machines where the balled-tip workflow is preferred
• Critical aluminium welding where weld contamination from tungsten spitting is unacceptable — aerospace, marine, food-grade fabrication
• High-purity aluminium grades where tungsten contamination must be minimised

In modern AC inverter machines, 2% lanthanated with a pointed tip often outperforms zirconiated with a balled tip on aluminium. Zirconiated remains in service primarily on legacy transformer AC welders and in specific industries where the balled-tip protocol is tradition.

Rare-earth blends (EWG / purple) and recent specialty types

EWG ("rare earth, unspecified" — purple band) is the AWS A5.12 category for manufacturer-specific rare-earth oxide blends that don't fit the named categories. Specific commercial examples:

• Multi-Strike (Diamond Ground Products) — purple band, proprietary rare-earth blend designed for universal AC/DC use with extended arc life
• Tri-Mix — multiple manufacturer proprietary blends with various rare earth combinations

These specialty electrodes target the same universal-use position as lanthanated and offer comparable performance. The practical buying-decision difference: lanthanated has the longest track record and broadest workshop familiarity. Specialty blends offer modest performance gains in specific applications but require workshop training to use effectively.

DC vs AC tungsten selection — the decision matrix

Mode	Material	Recommended tungsten	Tip geometry
DCEN (DC straight polarity)	Carbon steel	2% lanthanated (blue) — workshop default. 2% thoriated (red) as legacy alternative.	Sharpened point, 20-30° included angle
DCEN	Stainless steel	2% lanthanated (blue) — preferred for tip longevity. 2% ceriated (grey) for low-amperage thin section.	Sharpened point with truncated tip 0.13-0.25 mm flat
DCEN	Chrome-moly (P11, P22, P91)	2% lanthanated (blue) — best electrode life on Cr-Mo	Sharpened point, 25-30° included angle
DCEN	Titanium	2% lanthanated (blue) — high-purity argon required + back purge	Sharpened point, 20-25° included angle, truncated tip
DCEN	Copper and copper alloys	2% lanthanated (blue) — high amperage typical	Sharpened point, 30-45° included angle
DCEN	Orbital tube welding (low amp)	2% ceriated (grey)	Sharpened point, 15-20° included angle
DCEP (DC reverse polarity, rare)	Aluminium thin section	2% lanthanated or larger diameter — electrode runs hot	Balled tip required (electrode-positive heats tip)
AC (square-wave inverter)	Aluminium	2% lanthanated (blue) — modern workshop default with pointed tip	Sharpened point, 30-45° included angle, slight truncation
AC (transformer / sine wave)	Aluminium	Pure tungsten (green) — balled tip workflow. EWZr-8 (white) as enhanced alternative.	Balled tip, 1-1.25× electrode diameter
AC (transformer)	Magnesium	Pure tungsten (green)	Balled tip, 1-1.25× electrode diameter

The simplest practical workshop rule: stock 2% lanthanated (blue) in 1.6 mm, 2.4 mm and 3.2 mm sizes. It covers 90%+ of AU general workshop TIG work across DC steel, DC stainless, DC chrome-moly, and AC aluminium with modern inverter machines. Add ceriated (grey) for low-amperage specialty work, and pure tungsten (green) if running a transformer-based AC machine for aluminium. Browse AIMS TIG tungsten range for current stocked sizes and types.

Sizing tungsten by amperage — diameter selection rule

Tungsten diameter	DC amperage range	AC amperage range	Typical use
1.0 mm (0.040")	5-60 A	5-30 A	Thin sheet, miniature parts, orbital tube
1.6 mm (1/16")	30-150 A	20-100 A	General workshop steel/stainless thin to medium
2.4 mm (3/32")	50-200 A	30-180 A	The workshop default — covers medium-section work
3.2 mm (1/8")	100-300 A	60-250 A	Heavy-section steel and aluminium
4.0 mm (5/32")	200-400 A	100-350 A	Heavy fabrication, structural welding
4.8 mm (3/16")	300-500+ A	200-450+ A	Specialty heavy-section work

Two practical sizing failures show up regularly in workshop welds:

• Oversize tungsten — running 3.2 mm at 60 A or 2.4 mm at 30 A. The arc has trouble starting because the amperage isn't high enough to heat the larger electrode to emission temperature. Symptoms: erratic starts, wandering arc, poor puddle control.
• Undersize tungsten — running 1.6 mm at 180 A or 2.4 mm at 250 A. The electrode tip melts because amperage exceeds tip dissipation capacity. Symptoms: tip droops or melts off into the puddle, weld contaminated, electrode requires regrinding mid-job.

The workshop discipline: match tungsten diameter to peak amperage of the job, not to a single fixed stock size. 1.6 mm, 2.4 mm and 3.2 mm covers 95% of general fabrication; adding 1.0 mm covers thin work; adding 4.0 mm covers heavy structural. View AIMS tungsten size range.

The sharpening science — point angle, truncated tip, lengthwise grinding

Tungsten sharpening is the single most-discussed TIG technique on welding forums because the practitioner discipline directly affects every weld. Three rules emerge consistently across Practical Machinist, WeldingWeb, Miller Welding and Diamond Ground Products published guidance.

Rule 1 — Point angle scales with amperage.

• Sharp 10-15° included angle for low amperage (under 50 A). Sharp point gives precise arc starting and narrow arc cone for thin-section work.
• Moderate 20-30° included angle for general workshop amperage (50-200 A). The workshop default — balances arc precision against tip durability.
• Obtuse 30-60° included angle for higher amperage (200+ A). The blunter tip resists melting and provides broader arc cone for wider puddle.

Rule of thumb from Diamond Ground Products: grind length 2 to 2.5 times the electrode diameter. For 2.4 mm tungsten that means a 4.8-6 mm conical grind length. Tighter gives sharper point; looser gives more obtuse.

Rule 2 — Truncate the absolute tip for higher amperage.

A pure sharp point works at low amperage but melts at high amperage. The fix is a small truncation flat at the very tip — typically 0.13 mm (0.005") to 0.25 mm (0.010") — that prevents tip melting and arc wander. The truncation looks like the point has been clipped — it has. Practitioner warning across multiple forum threads: an over-truncated tip (more than ~0.5 mm flat) creates arc starting difficulty; under-truncated (no flat at all) melts at production amperage.

Rule 3 — Grind LENGTHWISE, not crosswise.

This is the most-overlooked sharpening detail. Current flows from the body of the electrode to the tip along the surface, following the grind marks. Crosswise grind marks create radial current scatter — the arc lights up multiple grind grooves rather than concentrating at the tip. Lengthwise grind marks channel the current to the tip cleanly. The result is a more stable, more centred arc.

Practitioner discipline: orient the electrode with its long axis perpendicular to the grinding wheel face so the grind marks run from body to tip, not around the circumference. A tungsten ground crosswise looks fine visually but produces a noticeably wandering arc compared to the same tungsten ground lengthwise.

Sharpening tools — dedicated grinder vs bench grinder reality

The practitioner conversation about how to sharpen tungsten splits across three approaches.

Approach 1 — Dedicated tungsten grinder. Diamond Ground Products, ArcZone, Sumig and several other manufacturers produce dedicated tungsten sharpeners. They hold the electrode at a controlled angle, grind with a diamond wheel optimised for tungsten carbide, and include integral dust extraction. The workshop standard for any production TIG operation. Cost is significant but tip consistency, safety (especially for thoriated grinding), and electrode life all benefit.

Approach 2 — Bench grinder with dedicated tungsten wheel. A standard bench grinder fitted with a green silicon-carbide or diamond wheel dedicated to tungsten only. The wheel must never grind steel, aluminium or other materials — cross-contamination embeds particles into the tungsten tip and into subsequent welds. Adequate for workshop use provided the dedicated-wheel discipline holds.

Approach 3 — Bench grinder shared with general workshop use. Practitioner consensus across forum threads: this is the contamination trap that causes more bad welds than any other TIG mistake. Grinding tungsten on a wheel that has previously ground steel or aluminium embeds those metal particles into the tungsten surface, then transfers them into the next weld. Weld contamination, porosity and arc instability follow. Where a workshop must use a shared bench grinder, the practitioner workaround is a dedicated grinding stone (silicon carbide stick) used only on a clean section of the wheel — but the result is still inferior to a true dedicated tungsten grinder.

For workshops grinding thoriated tungsten: local exhaust ventilation and P2 respirator are mandatory. Thorium oxide grinding dust is a respiratory carcinogen at chronic exposure levels. The dedicated tungsten grinder with integral extraction is the only fully-compliant solution. For workshops that have migrated entirely to lanthanated and ceriated, the dust hazard is reduced to general nuisance dust but extraction remains best practice. View AIMS welding PPE range.

AC aluminium ball-tip procedure — when, how, and why

On older transformer-based AC TIG machines, the standard preparation for aluminium welding is to ball the tungsten tip before commencing the weld. Modern square-wave inverter AC machines often work better with a sharpened pointed tip on lanthanated tungsten — but the balled-tip workflow remains widely practised in AU workshops with traditional AC welders.

The balling procedure:

1. Use pure tungsten (EWP / green) or zirconiated (EWZr-8 / white). Lanthanated and ceriated can be balled but the procedure is harder and the resulting ball less symmetric.
2. Set up clean copper or copper-alloy plate as a scrap target — not aluminium, not steel.
3. Set the machine to AC at moderate amperage (typically 100-150 A for 2.4 mm tungsten).
4. Strike an arc with high-frequency start (preferred) or scratch start on the copper.
5. Hold the arc steady for 2-3 seconds until the tip visibly melts and forms a hemisphere.
6. Ball diameter should be 1 to 1.25 times electrode diameter. 2.4 mm tungsten should ball to 2.4-3.0 mm. Smaller ball melts off mid-weld; larger ball produces wide unfocused arc.
7. Ball must be symmetric. An off-centre or pointed ball indicates uneven arc and will produce poor weld results. Re-ball if asymmetric.

Common balling mistakes:

• Balling on aluminium scrap — contaminates the tungsten with aluminium
• Insufficient amperage — fails to fully melt and form symmetric ball
• Excessive amperage — over-melts and ball drops off into copper
• Re-using a contaminated ball — old aluminium in the tip from a previous weld touches puddle, makes the contamination worse

For modern square-wave inverter AC machines: skip balling entirely. Use 2% lanthanated (blue) with a sharpened point and let the inverter electronics handle the AC waveform. The pointed-tip approach often produces cleaner AC aluminium welds than the balled-tip approach on modern machines.

Thoriated radioactivity safety — AU regulatory context

Thorium-232 in thoriated tungsten emits alpha radiation. The electrode itself is not dangerous to handle — alpha particles are stopped by skin or gloves. The hazard is exclusively in grinding dust, which contains thorium oxide particles small enough to be inhaled. Chronic inhalation can lead to thorium accumulation in lung tissue and bone.

The AU regulatory and best-practice framework:

• AS/NZS 1674.2 — Safety in welding and allied processes covers ventilation and respiratory protection for welding operations including tungsten grinding.
• SafeWork Australia — Hazardous Chemicals Code of Practice covers occupational exposure limits for radioactive dust.
• ARPANSA (Australian Radiation Protection and Nuclear Safety Agency) regulates radioactive substances. Thoriated tungsten as supplied is not regulated as a controlled radioactive material because the activity level is low; the grinding waste, however, has regulatory implications in some jurisdictions.
• State-based EPA disposal rules classify thoriated tungsten grinding residue as low-level radioactive waste. Disposal cannot be via general waste; collection by licensed radioactive waste handler is required in NSW, Vic and other states.

Practical workshop safety controls:

• Dedicated tungsten grinder with integral dust extraction (HEPA-filtered if grinding thoriated)
• Local exhaust ventilation at the grinder station — minimum 0.5 m/s capture velocity at the source
• P2 respirator minimum during grinding; P3 recommended for thoriated-specific work
• Gloves to prevent skin contact with grinding dust
• Wet-cleaning of grinding station surfaces (not dry sweeping which re-suspends dust)
• Grinding residue collected and disposed of via licensed radioactive waste handler

The migration path most AU workshops have taken: switch entirely to lanthanated (or ceriated for low-amp specialty work) and eliminate thoriated from the workshop. The performance equivalence is well-documented; the safety improvement is significant; the cost premium is modest. Lanthanated electrodes in the AIMS Bossweld range cover virtually every application thoriated did. Browse AIMS lanthanated tungsten range.

Contamination, regrinding, and practitioner discipline

The single most-cited TIG practitioner discipline across all welding forums: if the tungsten touches the weld puddle or the filler rod, stop welding, regrind, restart. A contaminated tungsten produces:

• Erratic arc behaviour — arc wanders, sputters, won't strike consistently
• Puddle inclusions — bits of tungsten in the weld creating inclusion defects
• Discoloured weld appearance — tungsten contamination shows as dark spots or smears in the bead
• Reduced weld strength — tungsten inclusions are stress concentrators that crack under load

The trap: contaminated tungsten still welds. The arc still strikes, the puddle still forms, the welder can keep going. The contamination shows up in weld appearance and especially in radiographic or dye-penetrant testing afterwards. Production discipline says: any tungsten-to-puddle or tungsten-to-rod touch = stop, regrind, restart.

How tungsten touches the puddle:

• Operator inattention — torch dipped too close while watching filler rod
• Wrong arc length — arc length should be approximately 1× electrode diameter. Shorter than this risks tungsten-to-puddle contact.
• Filler rod touches tungsten — rod dipped too far forward, touches the electrode
• Workpiece deflection or fixture failure — workpiece lifts unexpectedly into the electrode
• Electrode stick-out wrong — too much electrode protruding from gas cup, vibrations cause tip excursion

Workshop discipline elements:

• Re-sharpen every shift minimum for production work, more often for critical welds
• Visually inspect tip before every weld — black discoloration, irregular shape, or visible inclusions = regrind
• Carry multiple pre-ground tungstens in a tungsten storage case — quick swap rather than mid-job regrind
• Don't reuse balled tungsten across materials — a tungsten balled for aluminium contaminates with aluminium and cannot be reused on steel without regrinding

The AIMS supply story — Bossweld and the AU welding market

AIMS Industrial stocks a comprehensive range of TIG tungsten electrodes covering the major types and sizes that AU workshops need. Primary brand:

• Bossweld — Australian-engineered welding consumables, dominant in the workshop TIG tungsten market. Full range of pure (EWP green), 2% lanthanated (EWLa-2 blue), 1.5% lanthanated (EWLa-1.5 gold), 2% ceriated (EWCe-2 grey), 2% thoriated (EWTh-2 red), and zirconiated (EWZr-8 white) in 1.0 mm, 1.6 mm, 2.4 mm and 3.2 mm × 150 mm standard length. Typically packaged in 10-piece packs.

Complementary brands sourced through the AIMS supply chain:

• Cigweld — long-established AU welding brand, full tungsten range
• UNIMIG — broad TIG/MIG accessory range with tungsten supply
• Welding Industries Australia (WIA) — premium tier for specialty applications
• Diamond Ground Products — US specialty Multi-Strike and Tri-Mix rare-earth blends — sourced on request for specific applications

Standard sizing and packaging:

• Length — 150 mm (6") is the universal default. Some specialty 175 mm and 75 mm exist but 150 mm covers all standard TIG torches.
• Diameter range — 1.0 mm, 1.6 mm, 2.4 mm and 3.2 mm cover 95% of AU workshop demand. Larger 4.0 mm and 4.8 mm for heavy structural work; smaller 0.5 mm for miniature/orbital specialty.
• Pack sizes — 10-piece packs are workshop standard. Bulk 50 and 100-piece packs for production users.

For TIG welding consumables more broadly — collets, collet bodies, gas cups, gas lenses, back caps, and TIG torch parts — browse the AIMS TIG welding accessories range. For TIG welders themselves see the AIMS TIG welder range. For broader welding context see our TIG Welding Guide, Welding Consumables Guide, and MIG vs TIG vs Stick Welding.

Need help selecting tungsten for a specific application? AIMS has a technical desk staffed by people who weld. Contact our team or call (02) 9773 0122 with your machine, material and amperage range — we'll get you the right type and size first time.

Frequently asked questions

What colour is 2% lanthanated tungsten?

2% lanthanated tungsten (AWS classification EWLa-2 or WL20) has a BLUE colour band painted at one end of the electrode. It is the modern workshop default for general TIG welding across DC steel, DC stainless and AC aluminium with square-wave inverter machines. Per Miller Welding and Practical Machinist forum consensus, 2% lanthanated offers the best balance between arc starting, stability and electrode longevity across the broadest range of TIG applications.

What is the difference between thoriated and lanthanated tungsten?

Thoriated tungsten (EWTh-2 red, 2% thorium oxide) was the welding industry standard from the 1950s to early 2000s but contains radioactive thorium-232 — the grinding dust is an inhalation hazard. Lanthanated tungsten (EWLa-2 blue or EWLa-1.5 gold) uses non-radioactive lanthanum oxide and delivers equal or better arc starting, stability and longevity. Modern AU workshops have largely migrated from thoriated to 2% lanthanated to eliminate the radioactivity hazard with no performance loss. Thoriated is not banned but requires dedicated tungsten grinder, local exhaust ventilation and licensed waste handling.

What tungsten should I use for aluminium TIG welding?

For modern AC square-wave inverter TIG machines: 2% lanthanated (blue) with a sharpened point produces excellent AC aluminium welds. For older transformer-based AC TIG machines using the balled-tip workflow: pure tungsten (EWP green) is traditional, with zirconiated (EWZr-8 white) as an improved alternative offering longer electrode life and less tungsten spitting. The balled tip diameter should be 1 to 1.25 times electrode diameter, formed by initial arc strike on clean copper scrap. Never ball on aluminium scrap as it contaminates the tip.

What tungsten should I use for stainless steel TIG welding?

2% lanthanated (EWLa-2 blue) is the modern workshop standard for DC stainless steel TIG. It delivers excellent arc starting, stable arc behaviour and the longest electrode life on stainless and chrome-moly work compared to thoriated or ceriated. For low-amperage thin-section stainless work (under 100 A) or orbital tube welding, 2% ceriated (EWCe-2 grey) outperforms lanthanated at very low amperages. Sharpened point with truncated tip (0.13-0.25 mm flat) at 20-30 degree included angle is the standard geometry.

How do you sharpen a tungsten electrode?

Three rules: (1) Point angle scales with amperage — sharp 10-15 degrees for low amp, moderate 20-30 degrees for general workshop, obtuse 30-60 degrees for high amp. Grind length 2-2.5 times electrode diameter. (2) Truncate the absolute tip with a 0.13-0.25 mm flat to prevent tip melting at higher amperage — pure sharp points melt above 100 A. (3) Grind LENGTHWISE not crosswise — orient the electrode so grind marks run from body to tip, not around the circumference. Current follows the grind marks; lengthwise grinding channels current to the tip cleanly, while crosswise creates radial scatter and arc wander.

Why must I grind tungsten lengthwise and not crosswise?

Current flows from the body of the electrode to the tip along the surface, following the grind marks. Crosswise grind marks create radial current scatter — the arc lights up multiple grind grooves around the circumference rather than concentrating at the tip. Lengthwise grind marks channel the current cleanly to the tip. The result is a more stable, more centred, more predictable arc. Visually the two grinds look similar, but practitioner reports consistently show noticeable arc behaviour difference. Orient the electrode with its long axis perpendicular to the grinding wheel face.

Is thoriated tungsten dangerous to use?

Thoriated tungsten contains thorium-232 which emits alpha radiation. The electrode itself is not hazardous to handle — alpha particles are stopped by skin or gloves. The hazard is exclusively in grinding dust which contains thorium oxide particles small enough to inhale. Chronic inhalation accumulates thorium in lung tissue and bone, classified as a respiratory carcinogen at chronic exposure levels. Safe use requires dedicated tungsten grinder with integral dust extraction, local exhaust ventilation, P2 minimum (P3 recommended) respirator during grinding, and licensed radioactive waste disposal of grinding residue. Most AU workshops have migrated to non-radioactive lanthanated as the safer alternative with equivalent performance.

What is the AWS A5.12 standard?

AWS A5.12M/A5.12:2009 is the American Welding Society specification for tungsten and oxide-dispersed tungsten electrodes for arc welding and cutting. Modified from ISO 6848:2004. Defines the eight major tungsten electrode types (EWP pure, EWCe-2 ceriated, EWLa-1.5 and EWLa-2 lanthanated, EWTh-2 and EWTh-4 thoriated, EWZr-1 and EWZr-8 zirconiated, EWG rare earth), the colour-code identification system, oxide content tolerances, dimensions and packaging. The Australian adoption is AS/NZS 1167.5. ISO 6848 is the international peer.

What size tungsten should I use?

Match diameter to peak amperage of the job. 1.0 mm covers 5-60 A on DC and 5-30 A on AC (thin sheet, orbital tube). 1.6 mm covers 30-150 A DC and 20-100 A AC (general workshop thin-medium). 2.4 mm is the workshop default at 50-200 A DC and 30-180 A AC (medium-section work). 3.2 mm covers 100-300 A DC and 60-250 A AC (heavy-section steel and aluminium). 4.0 mm covers 200-400 A for heavy fabrication. Oversize tungsten produces erratic arc starting because amperage is insufficient to heat the electrode to emission temperature. Undersize tungsten melts at the tip.

Can I sharpen tungsten on a bench grinder?

Conditionally — but only with a wheel dedicated exclusively to tungsten grinding. Sharing a bench grinder wheel between tungsten and steel, aluminium or other materials embeds those metal particles into the tungsten tip and transfers them into the next weld, causing contamination, porosity and arc instability. The practitioner consensus across welding forums: shared bench grinder is the contamination trap that causes more bad TIG welds than any other mistake. The workshop standard is either a dedicated tungsten grinder (Diamond Ground, ArcZone, Sumig — purpose-built with diamond wheel and dust extraction) or a dedicated silicon-carbide wheel reserved exclusively for tungsten. For thoriated grinding, dedicated grinder with HEPA-filtered extraction is mandatory.

Why does tungsten get contaminated and what do I do about it?

Tungsten gets contaminated when it touches the weld puddle or filler rod during welding, when the workpiece deflects unexpectedly into the electrode, when arc length is too short, when filler rod is dipped too far forward, or when electrode stick-out from the gas cup is excessive. The contamination shows as black discoloration, irregular tip shape, or visible inclusions. A contaminated tungsten still strikes an arc — but produces erratic arc behaviour, puddle inclusions, discoloured weld appearance and reduced weld strength. The practitioner discipline is unambiguous: any tungsten-to-puddle or tungsten-to-rod touch means stop, regrind, restart. Carry multiple pre-ground tungstens in a storage case for quick swap rather than mid-job regrind.

What is the difference between 1.5% and 2% lanthanated tungsten?

Both are non-radioactive lanthanum-oxide tungsten electrodes. EWLa-1.5 (gold band, 1.5% lanthanum oxide) is balanced for general workshop TIG across DC and AC. EWLa-2 / WL20 (blue band, 2% lanthanum oxide) has better tip life at high amperage and is the modern workshop universal default. The performance difference at typical workshop amperages is modest — both deliver excellent arc starting, stability and longevity. For workshops standardising on a single tungsten type, 2% lanthanated (blue) is the recommended choice covering DC steel, DC stainless, DC chrome-moly and AC aluminium with modern inverter machines.

What is ceriated tungsten best for?

2% ceriated tungsten (EWCe-2 grey band) is the low-amperage specialist. It delivers consistent arc starts and stable narrow arc at very low amperages (under 100 A) where lanthanated and thoriated are less reliable. Primary applications are orbital tube welding (pharmaceutical, semiconductor, food processing tubing), thin-section sheet metal under 1.5 mm aluminium or stainless, and DC pulse TIG with sub-100 A peaks. Critical practitioner warning: at higher amperages the cerium oxide migrates quickly from the electrode body to the heated tip, depleting the oxide content and degrading electrode performance to pure-tungsten equivalent. Practical rule: ceriated below 100 A, lanthanated above 100 A.

How do you ball a tungsten electrode for AC aluminium welding?

Use pure tungsten (EWP green) or zirconiated (EWZr-8 white) — lanthanated balls less symmetrically. Set up clean copper scrap as the target (never aluminium — contaminates the tip). Set the machine to AC at moderate amperage (100-150 A for 2.4 mm tungsten). Strike an arc with high-frequency start, hold steady for 2-3 seconds until the tip melts to a hemisphere. Ball diameter should be 1 to 1.25 times electrode diameter — 2.4 mm electrode balls to 2.4-3.0 mm. Ball must be symmetric; re-ball if asymmetric. For modern AC square-wave inverter machines, skip balling and use 2% lanthanated with a sharpened point — often produces cleaner welds than the balled-tip workflow on modern equipment.

What tungsten does AIMS Industrial stock?

AIMS stocks a comprehensive Bossweld TIG tungsten range covering all major types: pure (EWP green), 2% lanthanated (EWLa-2 blue), 1.5% lanthanated (EWLa-1.5 gold), 2% ceriated (EWCe-2 grey), 2% thoriated (EWTh-2 red), and zirconiated (EWZr-8 white) in 1.0 mm, 1.6 mm, 2.4 mm and 3.2 mm × 150 mm standard length, typically packaged in 10-piece packs. Complementary brands including Cigweld, UNIMIG and WIA are also stocked or sourced. For broader TIG welding consumables (collets, collet bodies, gas cups, back caps) AIMS supplies a full TIG accessory range. For specific selection advice contact the AIMS technical team on (02) 9773 0122.