The Harris ER4043 Aluminum GTAW Aluminum Welding TIG Rod (part number 04043305) is a fine-diameter, silicon-alloyed aluminum filler metal classified ER4043 per AWS A5.10/A5.10M. Available in a 1/16 in (1.6 mm) diameter, 36-inch cut length, 5 lb box, this rod is the correct choice for precision TIG welding of thin-gauge and small-section aluminum components in 6061, 6063, 3003, and cast aluminum alloys. Harris Products Group, a Lincoln Electric company, produces this rod with consistent silicon content (4.5–6.0%) and tight dimensional tolerances for reliable arc starts and smooth bead formation at low amperage settings. The 1/16 in diameter is particularly valuable for: welding aluminum sheet below 1/8 in thickness where the 3/32 in rod deposits too much filler per unit length, precision TIG work on aluminum tube fittings and manifolds, casting repair on small investment castings and die castings, and detailed automotive fabrication on thin aluminum body panels.
The 5 lb box format (approximately 400–450 individual 36-inch rods) is sized for job shop and prototype/repair work where a full 10 lb box would sit open for extended periods and risk moisture absorption. The 1/16 in diameter in a 5 lb box provides an economical quantity for shops needing fine-diameter aluminum TIG capability without committing to the full 10 lb production quantity.
| Attribute | Value |
|---|---|
| AWS Classification | ER4043 (AWS A5.10/A5.10M) |
| Harris Part Number | 04043305 |
| Diameter | 1/16 in (1.59 mm) |
| Cut Length | 36 in (914 mm) |
| Package Weight | 5 lb box |
| Silicon Content | 4.5–6.0% |
| Copper (max) | 0.30% |
| Manganese (max) | 0.05% |
| Magnesium (max) | 0.05% |
| Tensile Strength (as welded) | ≥29,000 psi (200 MPa) |
| Yield Strength (as welded) | ≥21,000 psi (145 MPa) |
| Elongation (as welded) | ≥10% |
| Polarity | AC (Alternating Current) |
| Shielding Gas | 100% Argon |
| Process | GTAW (TIG) |
| Compatible Base Metals | 6061, 6063, 3003, 1100, 356 castings |
- Thin-Gauge 6061 Sheet (0.040–0.125 in): Chassis panels, fairings, instrument enclosures, and sheet metal fabrication in 6061-T6 and 6063 where the 3/32 in rod would overfill the joint. The 1/16 in diameter provides precise heat and filler control on thin sheet, reducing distortion and burn-through.
- Small-Bore Aluminum Tubing: 1/4 in to 3/4 in OD aluminum tube assemblies, instrument manifolds, and pneumatic plumbing where the joint geometry is too small for 3/32 in filler. The 1/16 in diameter fits naturally in small-radius corners and tight joint access situations.
- Aluminum Casting Repair — Small Parts: Carburetor bodies, small valve housings, die-cast housings with porosity or cracks, and investment cast aluminum parts with defects. The 1/16 in diameter allows precise filler addition in small areas without flooding adjacent thin sections.
- Automotive Precision Work: Custom aluminum intake runners, throttle body flanges, small radiator tanks, and specialized aluminum brackets. Detail work that demands the fine control only a small-diameter filler rod provides.
- Aluminum Sheet Metal Fabrication: Boxes, enclosures, and custom sheet metal work in 3003 or 5052 aluminum at 0.040–0.100 in thickness; the 5 lb box size matches typical small-shop consumption for these occasional jobs.
- Educational & Training: Welding programs and training centers that teach aluminum TIG typically start students on 1/16 in filler on 1/8 in aluminum plate — the smaller diameter is easier to manipulate and feed at training amperage settings (60–90 A).
The 1/16 in ER4043 rod setup is identical in process to the 3/32 in, with adjusted parameters for the finer diameter and thinner material it's typically used on:
Amperage: 50–120 A AC for most 1/16 in rod applications. For 1/16 in base metal sheet, run 50–70 A with a foot pedal and modulate carefully — thin aluminum reaches burn-through quickly. For 3/16 in plate, 120 A provides adequate fusion with 1/16 in rod, though deposition rate is slower than 3/32 in rod.
Tungsten: 1/16 in 2% ceriated tungsten works well with 1/16 in rod on thin aluminum. For applications above 100 A, use 3/32 in ceriated tungsten. On inverter machines, the ceriated tungsten forms a proper ball at AC current; maintain a moderate ball of 1.5–2x the electrode diameter. An excessively large ball on 1/16 in tungsten may wander — if this occurs, trim back the tungsten and reform the ball at correct amperage.
AC Balance & Frequency: Same recommendations as for 3/32 in rod. On thin aluminum, use 70–75% EN balance (less cleaning) to reduce heat input. For contaminated or heavily oxidized base metal, increase cleaning (lower EN to 65%). Frequency 80–120 Hz for thin aluminum to focus the arc and reduce input per cycle.
| Base Metal Thickness | Amperage (AC) | Tungsten | Ar Flow CFH |
|---|---|---|---|
| 16–18 gauge (0.050–0.063 in) | 50–70 A | 1/16 ceriated | 18–20 |
| 12–14 gauge (0.078–0.109 in) | 70–95 A | 3/32 ceriated | 20 |
| 1/8 in (0.125 in) | 90–115 A | 3/32 ceriated | 20–22 |
| 3/16 in (0.188 in) | 115–140 A | 3/32 ceriated | 22 |
Joint Preparation: On thin aluminum (below 1/8 in), use a square butt joint — V-groove preparations are not necessary and can increase burn-through risk. On 1/8–3/16 in plate, a slight 30–45° bevel on a single-sided butt joint improves penetration and eliminates the need for a root pass with 1/16 in filler. Clean the joint with acetone and stainless wire brush immediately before welding.
- Moisture Control Critical: The 1/16 in diameter has high surface area to volume ratio — moisture absorption is proportionally more impactful than on larger-diameter rods. Keep the 5 lb box sealed except during active welding. Opened boxes should be stored in a sealed plastic bag with a desiccant packet in a temperature-stable location.
- Avoid Cold Storage: Do not store in unheated areas where the rod can cycle below and above dew point. Condensation on cold aluminum rod is a primary source of hydrogen porosity. Bring rods to a stable room temperature before welding.
- Kink Prevention: The 1/16 in diameter is more susceptible to kinking than 3/32 in rods. Handle the box carefully and do not allow rods to be bent or dropped. Kinked sections create arc disturbances at the bend point — discard kinked rods rather than risk inconsistent welds.
- Small Quantity Advantage: The 5 lb box is intentionally sized to be consumed before significant moisture uptake occurs in normal shop conditions. Replace older boxes rather than risk porosity from rods that have been open for more than 3–6 months in a humid environment.
- Pre-Weld Rod Dry: For critical work, wipe individual rods with a clean acetone-dampened rag before use to remove any surface moisture or fingerprints, even from properly stored boxes.
Any AC TIG machine is compatible with 1/16 in ER4043. For thin aluminum, low-amperage arc stability is important:
- Lincoln Electric Square Wave TIG 200 (K5126-1): Ideal machine for 1/16 in ER4043 work on thin-gauge aluminum. The HF start provides reliable arc initiation at low amperage (50 A and below). Square wave AC output on this machine is well-suited for thin aluminum with precise amperage control.
- Any AC/DC TIG machine with foot pedal control: A foot pedal is essentially mandatory for 1/16 in rod work on thin aluminum. The ability to ramp down amperage as the weld pool heats up prevents burn-through on thin sections and taper-weld terminations.
| Base Metal | ER4043 1/16 Compatibility | Notes |
|---|---|---|
| 6061-T6 / 6061-T4 (thin) | ✅ Primary | Most common 1/16 in application |
| 6063 (thin extrusions) | ✅ Primary | Window frames, thin architectural extrusions |
| 3003 / 3004 sheet | ✅ Excellent | Roofing, automotive trim, signage |
| 1100 aluminum | ✅ Excellent | Pure aluminum sheet, foil, and deep-drawn parts |
| 356 / A356 small castings | ✅ Primary | Investment and sand castings; fine diameter for precision repair |
| 5052 sheet | ✅ Acceptable | ER5356 preferred for marine 5052 service; ER4043 acceptable for non-marine |
The 1/16 in (1.587 mm) diameter ER4043 rod is the precision-work size for aluminum TIG, covering the thin-gauge and automotive aluminum applications where the larger 3/32 in rod delivers too much filler per arc dip for controlled puddle management.
| Parameter | 1/16 in ER4043 | 3/32 in ER4043 |
|---|---|---|
| Best base thickness | 0.040–0.090 in (18–14 ga) | 0.090–0.250 in (14–8 ga) |
| Typical amperage | 40–120 A AC | 100–200 A AC |
| Applications | Automotive body, thin tube, extrusions | Structural plate, marine, trailers |
| Package weight | 5 lb box | 10 lb box |
Modern automotive aluminum components in 6000-series (6061, 6063, 6082) and 5000-series (5052) are joined by TIG welding in aftermarket performance fabrication and OEM prototype production. Harris ER4043 1/16 in rod is the standard choice for:
- Intake manifolds and plenums: Cast aluminum A356/A380 to 6061 plate TIG joints. ER4043's high Si content provides excellent fluidity on A356 castings where porosity and oxide inclusions create difficult root fusion.
- Intercooler tanks and end caps: 0.060–0.090 in 3003 aluminum sheet TIG joints. 1/16 in rod balances filler volume to the thin tank wall for consistent root fusion on box-welded tank corners.
- Suspension brackets and linkages: 6061-T6 plate 0.075–0.125 in. ER4043 prevents hot tearing on 6061 that would result from autogenous TIG or ER5356 filler on this alloy.
- Aluminum radiator tanks: 0.050–0.080 in 3003/3105 aluminum. Very low amperage (50–80 A), small puddle, 1/16 in rod provides the fine control needed on radiator tank sheet.
Aluminum TIG requires AC (alternating current) for oxide removal via the EP (electrode positive) half-cycle. Key parameters for 1/16 in ER4043 on 6061:
- AC frequency: 80–120 Hz for most aluminum. Higher frequency (120–200 Hz) produces a tighter, more focused arc — better for thin gauge and precise welds. Lower frequency (60 Hz) produces wider arc cleaning action, useful on oxidized or anodized surfaces.
- AC balance: 65–75% EN (electrode negative) side is standard. Higher EN % increases penetration; lower EN (more EP) increases oxide cleaning but increases tungsten erosion. For thin 6061, 65–70% EN is recommended.
- Tungsten: Pure tungsten (green band) — develops a balled end on AC, which is correct for aluminum. 3/32 in pure tungsten for 60–160 A. Do not use ceriated or lanthanated tungsten on AC aluminum (they split rather than ball).
- Shielding: 100% argon, 100% helium, or Ar/He blends. For thin 6061 below 0.090 in, 100% argon at 18–22 CFH. Helium blends for 6061 plate above 0.125 in to improve fusion.
Harris ER4043 rod is manufactured and lot-tested to AWS A5.10/A5.10M. Certified Material Test Reports (CMTRs) are available for aerospace, defense, and quality-system regulated applications requiring documentation of chemistry and mechanical properties. Contact Harris/Lincoln Electric for CMTR requests on specific production lot numbers.
Q1: Why is 1/16 in ER4043 rod preferred for thin aluminum over 3/32 in?
The 1/16 in rod deposits less filler per dip cycle at the same amperage, which allows the welder to control the fill volume more precisely on thin material. On base metal below 1/8 in, using 3/32 in rod requires operating at lower amperage with larger, less frequent dips — technique that results in uneven bead height and inconsistent fusion. The 1/16 in rod provides a smoother, more consistent weld profile on thin material with less risk of overfilling and more natural rhythm.
Q2: Can I use 1/16 in ER4043 on 1/4 in aluminum plate?
Technically yes, but it is inefficient. Welding 1/4 in aluminum with 1/16 in filler requires many rapid dipping cycles per inch of weld, which is slower and tiring compared to using 3/32 in rod. For material 3/16 in and above, the 3/32 in diameter is more practical. The 1/16 in diameter is best reserved for its intended range: below 3/16 in base metal or applications where the joint geometry requires a fine filler.
Q3: What amperage should I set for welding 1/8 in 6061-T6 with 1/16 in ER4043 rod?
Start at 90–100 A AC with foot pedal control. For a lap joint or T-joint on 1/8 in 6061, you may need to push toward 110 A to achieve full fusion on the bottom member. For a square butt joint on 1/8 in with good fit-up, 90–95 A typically provides clean, full-penetration beads with 1/16 in rod.
Q4: How many rods are in a 5 lb box of 1/16 in ER4043?
Approximately 420–460 individual 36-inch rods per 5 lb box, depending on exact linear weight. Each 36 in rod of 1/16 in ER4043 weighs approximately 10–12 grams. For thin-aluminum sheet work consuming 3–5 rods per 12 in of weld, a 5 lb box lasts through a substantial repair or fabrication project.
Q5: Can I store 1/16 in ER4043 rod in an open tray on my welding cart?
Not recommended. Open storage on a welding cart allows the rod to accumulate weld spatter, oil mist, and atmospheric moisture — all of which degrade arc quality and increase porosity risk on aluminum TIG. Store in the original closed box or sealed container and remove only the quantity needed for the current session. Return unused rods to the box.
Q6: Is there a difference between 1/16 in ER4043 and 0.045 in ER4043 for TIG welding?
Yes — 1/16 in (0.0625 in / 1.59 mm) is a slightly larger diameter than 0.045 in (1.14 mm). The 0.045 in diameter is extremely fine — rarely used in manual TIG welding and more commonly used in MIG wire format. For manual aluminum TIG, 1/16 in is the standard "fine diameter" choice; .030 in is used only in precision applications or orbital welding where minimum heat input is critical. 0.045 in TIG rod for aluminum is an uncommon specialty item.
Q7: Will ER4043 1/16 in work with AC pulse TIG on thin aluminum?
Yes. AC pulse TIG with 1/16 in ER4043 is an excellent technique for thin aluminum. Pulse settings: 100–150 Hz background frequency, 60–80% EN balance, 2–5 Hz pulse frequency with 30–40% peak on-time, and peak current approximately 40–50% above background. The pulsing reduces total heat input while maintaining adequate fusion, which minimizes warpage and HAZ width on thin 6061 or 3003 sheet. Feed the 1/16 in rod in time with the pulse peak for the most controlled deposition.