The Harris ER5356 GTAW Aluminum Welding TIG Rod (part number 0535650) is a magnesium-alloyed aluminum filler metal classified ER5356 per AWS A5.10/A5.10M. Available in a 3/32 in (2.38 mm) diameter, 36-inch cut length, 10 lb box, this rod provides higher strength, better corrosion resistance, and improved anodize color match compared to silicon-bearing ER4043 filler. Harris Products Group, a Lincoln Electric company, manufactures ER5356 with rigorous lot chemistry control — magnesium content is closely managed at 4.5–5.5% to deliver consistent mechanical properties and arc behavior. The 3/32 in diameter is the production workhorse size for structural aluminum work on 1/8 in–1/2 in plate, extrusions, and medium-wall tube.
ER5356 is the stronger aluminum TIG filler metal: as-welded tensile strength exceeds 40,000 psi (275 MPa) versus approximately 29,000 psi for ER4043. This strength advantage, combined with ER5356's superior resistance to seawater and marine atmospheric corrosion, makes it the standard choice for 5083, 5086, and 5454 marine-grade aluminum structures, anodized architectural assemblies, and high-cycle-load-bearing structural weldments where long fatigue life is required. The magnesium in ER5356 also provides an anodize color match to 6061 and 6063 base metals that is not achievable with silicon-rich ER4043, which anodizes to a darker grey-brown tone.
| Attribute | Value |
|---|---|
| AWS Classification | ER5356 (AWS A5.10/A5.10M) |
| Harris Part Number | 0535650 |
| Diameter | 3/32 in (2.38 mm) |
| Cut Length | 36 in (914 mm) |
| Package Weight | 10 lb box |
| Magnesium Content | 4.5–5.5% |
| Chromium | 0.05–0.20% |
| Manganese | 0.05–0.20% |
| Silicon (max) | 0.25% |
| Copper (max) | 0.10% |
| Titanium | 0.06–0.20% |
| Tensile Strength (as welded) | ≥40,000 psi (276 MPa) |
| Yield Strength (as welded) | ≥28,000 psi (193 MPa) |
| Elongation (as welded) | ≥17% |
| Polarity | AC (Alternating Current) |
| Shielding Gas | 100% Argon |
| Process | GTAW (TIG) |
| Compatible Base Metals | 5052, 5083, 5086, 5454, 5456, 6061, 6063 aluminum alloys |
- Marine & Offshore Structures: Boat hulls, offshore platform decks, bulkheads, and structural frames in 5083, 5086, or 5454 marine-grade aluminum alloys. ER5356 is the specified filler for marine aluminum by AWS D1.2 and most marine classification societies because its magnesium composition provides matching corrosion resistance in saltwater exposure.
- Structural Aluminum — High Load Applications: Lifting attachments, gusset plates, heavily loaded weld joints, and fatigue-critical structures require the higher strength of ER5356 (40 ksi tensile) over ER4043 (29 ksi). Structural aluminum per AWS D1.2 structural welding code uses ER5356 as one of the primary approved filler metals for pre-qualified WPSs on 5xxx and 6xxx base metals.
- Architectural & Anodized Aluminum: Curtain walls, storefronts, window systems, and architectural extrusion assemblies in 6063-T5 or 6061-T6 where the welded joints will be anodized to match the base metal color. ER5356 anodizes to a silver-grey tone closely matching these alloys; ER4043 anodizes dark and is unacceptable for visible anodized joints.
- Transportation & Trailer Fabrication: Aluminum flatbed trailers, truck body panels, and dump body side plates in 5052 and 5083 alloys use ER5356 as the standard filler for structural welds that must withstand road-induced fatigue cycling.
- Pressure Vessels & Storage Tanks: Aluminum pressure vessels and cryogenic tanks in 5083 alloy (the primary cryogenic aluminum structural material); ER5356 is an approved filler metal per ASME Section VIII and AWS B2.1-aluminum WPS requirements for 5083 base metal.
- Mining & Industrial Fabrication: Structural aluminum components for conveyors, platforms, walkways, and equipment structures where strength and durability are prioritized over cosmetics.
ER5356 TIG welding setup is essentially the same as ER4043 with a few important notes specific to the magnesium-bearing alloy:
Polarity — AC Only: Like all aluminum TIG rods, ER5356 requires AC polarity for cathodic cleaning of the aluminum oxide layer. The AC balance control on modern inverter machines (60–75% EN) is particularly important for ER5356 on 5xxx series alloys, which tend to develop thicker oxide layers than 6061 in service. More cleaning (lower EN%) may be required on heavily oxidized 5083 material.
Hot-Cracking Note: ER5356 has slightly higher sensitivity to hot cracking (solidification cracking) than ER4043 on 6000-series alloys, particularly in high-restraint configurations (T-joints, fillet welds on thick section) of 6061-T6. If hot cracking is experienced when welding 6061 with ER5356, switch to ER4043 — this is the common recommendation in the AWS D1.2 guidance. For 5xxx series base metals, hot cracking is not typically an issue with ER5356.
Amperage & Tungsten: Identical to ER4043 3/32 in setup. Use 100–230 A AC depending on material thickness, 3/32 in or 1/8 in 2% ceriated tungsten for inverter machines, 100% argon at 20–25 CFH.
| Material Thickness | Amperage (AC) | Travel Speed | Passes | Notes |
|---|---|---|---|---|
| 1/8 in 6061 | 100–130 A | 5–7 in/min | 1 | ER5356 or ER4043 acceptable |
| 1/4 in 5083 marine plate | 175–210 A | 4–5 in/min | 1–2 | ER5356 primary; back-purge available |
| 3/8 in structural Al | 220–260 A | 3–4 in/min | 2–3 | 3/32 in filler; cool between passes |
| 1/2 in 5083 plate | 250–300 A | 3–4 in/min | 3–4 | High-amp machine required; interpass cool |
- Moisture Is the Enemy: Like all aluminum TIG filler, ER5356 must be stored dry. Magnesium in ER5356 is hygroscopic — it reacts with moisture more readily than the pure aluminum rods, making moisture porosity control even more important. Keep sealed in original packaging until use.
- Temperature Range: Store at 60–120°F, relative humidity below 50%. Pre-warm cold rods to room temperature before use. For critical marine or pressure vessel work, oven-dry at 250°F for 1–2 hours if humidity conditions have been marginal.
- Dedicated Brushes: Always use a stainless steel wire brush dedicated exclusively to aluminum (not mixed with steel or stainless) for surface preparation. The stainless brush removes the oxide layer without embedding iron particles that cause porosity and corrosion.
- Lot Identification: Retain the certificate of conformance from each 10 lb box. For ASME pressure vessel and AWS structural code work, the C/C chemistry and mechanical data are required for WPS/PQR documentation. ER5356 heat traceability is particularly important for AWS D1.2 structural aluminum applications.
- No Mixing with ER4043: The two rods look essentially identical in cut-length form. Label opened boxes prominently and store in separate locations. Accidental use of ER4043 on 5083 marine hull welds, or vice versa (ER5356 on a 6061 casting repair), can cause quality failures. Harris rod boxes are color-coded and labeled — keep the label visible.
ER5356 requires an AC TIG machine with adequate amperage for the section thickness:
- Lincoln Electric Square Wave TIG 200 (K5126-1): Suitable for ER5356 work on 1/16–1/4 in aluminum. The 200 A maximum is the practical limit; for heavier-section 5083 structural work, a higher-capacity machine is needed.
- Lincoln Electric Aspect 375 (K2459-2): 375 A AC/DC machine handles all ER5356 applications through 1/2 in aluminum plate. Adjustable frequency and balance controls optimize performance for both 5xxx and 6xxx base metals.
- Lincoln Electric Square Wave TIG 355 / 405: For heavy structural 5083 or 5086 marine aluminum work with 3/32 in ER5356 at high amperage on thick plate.
| Base Metal | ER5356 Compatibility | Notes |
|---|---|---|
| 5083 / 5086 / 5456 | ✅ Primary | Marine-grade alloys — ER5356 is the standard per AWS D1.2 and marine codes |
| 5052 / 5454 | ✅ Primary | Mid-strength marine alloys; ER5356 is standard |
| 6061-T6 (structural) | ✅ Acceptable (verify) | Check for hot cracking in high-restraint joints; use ER4043 if cracking occurs |
| 6063 (anodized finish) | ✅ Preferred (anodize match) | ER5356 is required when anodizing welded 6063 to match base metal color |
| 356 / A356 castings | ⚠️ Check | ER4043 preferred for cast aluminum repair; ER5356 may hot-crack on silicon-rich castings |
| 7075 / 2024 | ❌ | Non-weldable alloys — consult engineer |
ER5356 is the highest-strength standard aluminum TIG filler rod, with 40,000 psi tensile — significantly stronger than ER4043 (24,000 psi). This strength advantage makes ER5356 the preferred choice for structural aluminum welding, marine applications, and any joint where weld metal strength is engineered into the load path.
Harris ER5356 is classified per AWS A5.10/A5.10M: Mg 4.5–5.5% (primary strengthening element), Cr 0.05–0.20% (grain refinement, improved corrosion resistance), Mn ≤0.10%, Ti 0.06–0.20% (grain refinement), Si ≤0.25%, Cu ≤0.10%, Zn ≤0.10%, Al balance. The 5000-series (Al-Mg) classification produces high-strength, work-hardenable deposits with excellent resistance to seawater and marine atmosphere corrosion.
The strength of ER5356 comes from solid-solution hardening by magnesium (Mg): each 1% Mg adds approximately 3,000–4,000 psi to aluminum alloy tensile strength. With 4.5–5.5% Mg, the weld deposit achieves 40,000 psi tensile — comparable to 5052-H32 and 5083-H116 base metal tensile strengths. This allows structural engineers to design 5xxx-series aluminum weldments without reducing allowable stress at the weld joint, which is necessary when using the weaker ER4043 filler on 5xxx-series base metals.
For marine structural aluminum (5083, 5086, 5052, 5456) in saltwater service, ER5356 provides two advantages over ER4043:
- Corrosion resistance: 5xxx Al-Mg alloys with 4–5% Mg resist saltwater pitting and crevice corrosion better than 4xxx Al-Si alloys. Matching filler composition in ER5356 ensures the weld deposit has similar galvanic potential and passivation behavior as the base metal — preventing weld-zone preferential attack.
- Strength matching: Structural aluminum boat hulls, deck structures, and bulkheads require joint efficiency ≥0.90 (90% of base metal strength). ER4043 on 5083 base metal provides only ~60% joint efficiency — unacceptable for structural design. ER5356 provides 100%+ joint efficiency on 5052 and approximately 90% on 5083-H116.
ER5356 is the preferred aluminum TIG filler when weldments will be anodized (Type II or Type III hard coat). The Mg-based deposit anodizes in a color and finish very similar to 6061 and 5xxx base metals — the anodized weld bead is nearly invisible. ER4043's high silicon content produces a dark gray anodize deposit that creates highly visible dark-colored weld beads on clear-anodized finishes — unacceptable for architectural aluminum fabrication and consumer products requiring cosmetically uniform anodizing.
ER5356 deposits (and 5xxx-series Al-Mg alloys with >3% Mg) can become sensitized to intergranular corrosion after extended exposure to temperatures above 150°F (65°C). For this reason, ER5356 is NOT recommended for applications involving sustained elevated temperatures (engine cooling manifolds, elevated-temp process piping). In these applications, ER4043 (Al-Si, no Mg) is the correct choice. AWS D1.2 and Aluminum Association guidance explicitly warns against using ER5356 for high-temperature structural aluminum.
Q1: What is the main difference between ER5356 and ER4043 for aluminum TIG welding?
ER5356 is magnesium-bearing (4.5–5.5% Mg), producing stronger welds (≥40,000 psi tensile) with better marine corrosion resistance and improved anodize color match to 6000-series aluminum. ER4043 is silicon-bearing (4.5–6.0% Si), producing welds with lower cracking sensitivity, better fluidity, and lower strength (≥29,000 psi tensile). Choose ER5356 for marine structures, 5xxx series alloys, structural load-bearing welds, or when anodizing. Choose ER4043 for 6061 fabrication, casting repair, or when cracking is a concern.
Q2: Can ER5356 be used on 6061-T6 structural aluminum?
Yes, ER5356 is AWS D1.2 pre-qualified for 6061-T6 in non-high-crack-sensitivity joint geometries (simple butt welds, groove welds). However, in high-restraint fillet welds and T-joints on thick 6061-T6, hot cracking (solidification cracking) can occur with ER5356. AWS D1.2 guidance recommends switching to ER4043 if hot cracking develops when welding 6061 with ER5356. For most shop work, ER4043 is a safer choice on 6061; use ER5356 on 6061 primarily when post-weld anodizing is planned.
Q3: What is the as-welded strength of ER5356 welds on 6061-T6?
On 6061-T6 base metal, the weld joint as-welded tensile strength is governed by the heat-affected zone (HAZ), not the weld metal. The HAZ of 6061-T6 softens to approximately 18,000–22,000 psi tensile during welding due to over-aging of the T6 precipitate structure. This means the joint breaks in the HAZ at below 22,000 psi regardless of whether ER5356 (40 ksi wire) or ER4043 (29 ksi wire) is used. Post-weld T6 re-treatment (solution heat treat + aging) restores parent metal strength but is impractical for most welded assemblies.
Q4: Why does ER5356 look darker when anodized versus ER4043?
The reverse is true. ER4043 (silicon-rich) anodizes to a dark grey-brown because silicon disrupts the anodize oxide layer and does not produce a clear, consistent oxide film. ER5356 (magnesium-bearing) anodizes to a bright silver-grey that closely matches the appearance of 6061 and 6063 base metal. For any application where welded aluminum will be anodized, ER5356 is required for color consistency.
Q5: Does ER5356 require preheating?
Preheating is not required for ER5356 welding of 5xxx or 6xxx series alloys under normal shop conditions. For extremely thick sections (above 3/4 in) in cold environments (below 40°F), a mild 150°F preheat improves fusion and reduces solidification cracking risk. Do not preheat 6xxx series alloys above 250°F for reasons noted in Q3 — HAZ strength reduction increases with higher preheat on heat-treatable alloys.
Q6: Is there a shear strength advantage to ER5356 over ER4043?
Yes. ER5356's higher tensile and yield strength translates to higher shear strength in fillet welds subject to shear loading. For structural connections calculated per AWS D1.2, using ER5356 (effective throat strength basis ≥40 ksi) allows smaller weld sizes for the same load versus ER4043 (≥29 ksi), potentially reducing welding time and distortion on load-bearing structures. Verify with your structural engineer that ER5356 is used in the WPS if the design basis uses 40 ksi filler strength.
Q7: Can I use ER5356 for welding aluminum exhaust systems?
ER5356 should NOT be used for aluminum exhaust or high-temperature applications (above 150°F/65°C continuous service). The magnesium content in ER5356 makes the weld metal susceptible to stress corrosion cracking (SCC) in sensitized condition at elevated temperatures. AWS A5.10 and most engineering references classify ER5356 as "not suitable for elevated temperature service." For high-temperature aluminum applications (engine components, exhaust manifolds, turbo piping), use ER4043 which is not susceptible to SCC at elevated temperature.