ER4047 High-Silicon Aluminum Brazing & Welding Wire
ER4047 Amperage by Diameter
| Diameter | Amperage Range |
|---|---|
| 0.030" (0.8 mm) | 50 - 140A |
| 0.035" (0.9 mm) | 70 - 180A |
| 3/64" (1.2 mm) | 100 - 250A |
| 1/16" (TIG) (1.6 mm) | 60 - 120A |
| 3/32" (TIG) (2.4 mm) | 100 - 180A |
ER4047 is an aluminum-silicon alloy wire classified under AWS A5.10 containing approximately 12% silicon. The high silicon content produces the most fluid weld pool of any common aluminum filler metal, with a melting range of 1070-1080F (577-582C), well below the melting point of most aluminum base metals. This low melting point and high fluidity make ER4047 ideal for brazing, braze-welding, and welding applications where tight joints, thin material, or crack-prone castings require maximum wetting and minimal heat input. ER4047 produces less distortion and less porosity than ER4043 on many applications due to the lower welding temperature. The weld deposit is not anodizable (the high silicon turns dark gray when anodized). ER4047 is commonly used in automotive heat exchangers, radiator manufacturing, HVAC components, and repair of aluminum castings.
What This Means in Practice
ER4047 has roughly twice the silicon content of ER4043 (12% vs 5%). This extra silicon makes the weld pool extremely fluid with the lowest melting point of common aluminum fillers. The high fluidity fills tight joints and minimizes cracking. It is primarily used for brazing aluminum, welding castings, and joining thin aluminum where burn-through risk is high.
ER4047 Suitability Scores
How well this electrode matches common applications. Not a quality rating. all AWS-certified electrodes meet their specification.
When to Use ER4047
Use ER4047 for brazing or braze-welding aluminum, welding aluminum castings where maximum fluidity reduces cracking, joining thin aluminum where low heat input minimizes distortion, and manufacturing heat exchangers or radiator cores.
Suitable for 1xxx, 3xxx, and 6xxx series base metals where anodizing appearance is not a requirement.
ER4047 Limitations
Weld deposit is not suitable for anodizing (turns dark gray).
Lower tensile strength than ER5356.
Not suitable for structural applications requiring high weld strength.
Not compatible with 5xxx series aluminum (magnesium-silicon interaction causes cracking).
More specialized and expensive than ER4043.
ER4047 Storage Requirements
Store in sealed packaging. Aluminum wire oxidizes when exposed to air, reducing weld quality. Use within a reasonable time after opening.
ER4047 Technical Specifications
| Property | Value |
|---|---|
| AWS Classification | ER4047 |
| Process | aluminum-wire () |
| Polarity | DCEP |
| Positions | flat, horizontal, vertical up, overhead |
| Penetration | shallow |
| Coating Type | bare wire |
| Tensile Strength | 28,000 psi |
| Yield Strength | 15,000 psi |
| Elongation | 8% |
| Base Metals | 1xxx series aluminum, 3xxx series aluminum, 6xxx series aluminum, Aluminum castings (3xx.x series) |
| Shielding Gas | 100% Ar |
| AWS Specification | A5.10 |
Frequently Asked Questions
What is the difference between ER4047 and ER4043?
ER4047 contains approximately 12% silicon versus 5% in ER4043. This higher silicon content produces a more fluid weld pool with a lower melting temperature (1070F vs 1115F for ER4043). ER4047 is better for brazing, tight joints, and crack-prone castings. ER4043 is the general-purpose choice for most aluminum MIG and TIG welding. ER4047 is a specialty wire for specific applications.
Can I use ER4047 for structural aluminum welding?
No. ER4047 has relatively low tensile strength (28,000 psi versus 40,000 psi for ER5356) and is not suitable for structural applications. It is designed for brazing, heat exchangers, casting repair, and thin material where fluidity and low heat input are more important than weld strength.
Can I anodize welds made with ER4047?
No. The high silicon content (12%) causes the weld deposit to turn dark gray or black when anodized, creating an obvious contrast with the anodized base metal. If the finished part will be anodized, use ER5356 (which anodizes well) or ER4043 (which anodizes slightly darker but is acceptable for many applications).
External Resources
Manufacturer data sheets and standards for ER4047.
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.