ER4043 Aluminum Wire: MIG & TIG Amperage, Settings & Alloy Guide
ER4043 Amperage by Diameter
| Diameter | Amperage Range |
|---|---|
| .030" (0.8 mm) | 50 - 130A |
| .035" (0.9 mm) | 70 - 180A |
| 3/64" (1.2 mm) | 100 - 250A |
ER4043 is a silicon-alloyed aluminum filler wire used for MIG and TIG welding on most common aluminum alloys. The 5% silicon content lowers the melting point and improves fluidity, which means fewer hot cracks, easier bead starts, and smoother weld puddle control. It welds 1xxx, 3xxx, and 6xxx series aluminum alloys. The weld color will not match anodized base metal because the silicon content changes the surface appearance after anodizing. For general fabrication, repair work, automotive, marine, and most shop applications on 6061 or cast aluminum, ER4043 is the default wire. It forgives more operator error than ER5356.
What This Means in Practice
ER4043 means: ER (electrode rod for MIG/TIG) + 4043 (Aluminum Association alloy 4043, which is an Al-5%Si alloy). The 4xxx series aluminum alloys are silicon-alloyed, designed specifically as filler metals.
ER4043 Suitability Scores
How well this electrode matches common applications. Not a quality rating. all AWS-certified electrodes meet their specification.
When to Use ER4043
6061, 6063, 3003, and cast aluminum welding (MIG or TIG).
Automotive and marine aluminum repair.
General fabrication where anodized color match does not matter.
Brazing-like applications on thin aluminum.
Any situation where crack resistance is the priority.
ER4043 Limitations
Not for 5xxx series aluminum (5052, 5083, 5086), use ER5356 instead.
Weld beads will not match anodized color due to silicon content.
Lower shear strength in fillet welds compared to ER5356.
Not recommended where the weld will be exposed to sustained temperatures above 150 deg F (the dissimilar silicon creates a lower-melting eutectic).
ER4043 Storage Requirements
Keep sealed in original packaging. Store in dry environment. Aluminum wire oxidizes quickly when exposed to moisture.
ER4043 Technical Specifications
| Property | Value |
|---|---|
| AWS Classification | ER4043 |
| Process | MIG Welding (GMAW) |
| Polarity | DCEP |
| Positions | flat, horizontal, vertical up, overhead |
| Penetration | shallow |
| Coating Type | solid wire |
| Tensile Strength | 26,000 psi |
| Yield Strength | 11,000 psi |
| Elongation | 18% |
| Base Metals | 6061 aluminum, 6063 aluminum, 3003 aluminum, A356 cast aluminum, 1xxx series aluminum |
| Shielding Gas | 100% Argon |
| AWS Specification | A5.10 |
ER4043 Questions
When should I use ER4043 vs ER5356?
Use ER4043 for most general aluminum welding, especially 6xxx series alloys and castings. Use ER5356 for 5xxx series alloys, structural applications needing higher shear strength, and when anodizing color match matters.
Can ER4043 be used on all aluminum alloys?
No. ER4043 should not be used on 5xxx series alloys with more than 3% magnesium (like 5083, 5086, 5456) due to cracking risk. Use ER5356 for those.
What gas for aluminum MIG welding with ER4043?
Use 100% argon shielding gas for aluminum MIG welding. Do not use CO2 or argon/CO2 mixes as they cause contamination and porosity in aluminum welds.
Where to Buy ER4043
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External Resources
Manufacturer data sheets and standards for ER4043.
Data sourced from AWS A5.10/A5.10M. Amperage ranges are approximate starting points. adjust based on position, fit-up, and material thickness. Always follow manufacturer recommendations and applicable codes.