ER4047 High-Silicon Aluminum Brazing & Welding Wire
12% silicon aluminum wire for brazing, tight-joint welding, and applications needing maximum fluidity and crack resistance. Runs 50 to 180 amps on DCEP or AC, rated for flat, horizontal, vertical up, overhead. Amperage chart by diameter below.
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.
What Amps for ER4047?
| Diameter | Amperage Range |
|---|---|
| 0.030" (0.8 mm) | 50 - 140A |
| 0.035" (0.9 mm) | 70 - 180A |
| .045" (1.2 mm) | 100 - 250A |
| 1/16" (TIG) (1.6 mm) | 60 - 120A |
| 3/32" (TIG) (2.4 mm) | 100 - 180A |
Amperage by Individual Diameter
0.030 ER4047 Amperage
Set 0.030 ER4047 to 50 - 140 amps. Run DCEP or AC. This is the smallest available size. Best for vertical-up and overhead where you need a small, controllable puddle. Start around 95A.
0.035 ER4047 Amperage
Set 0.035 ER4047 to 70 - 180 amps. Run DCEP or AC. A versatile mid-range size. Start at 125A and adjust: lower for thin material and out-of-position work, higher for flat fillets on thicker stock.
.045 ER4047 Amperage
Set .045 ER4047 to 100 - 250 amps. Run DCEP or AC. A good choice when you need control. Run 100-175A for out-of-position work.
1/16 (TIG) ER4047 Amperage
Set 1/16 (TIG) ER4047 to 60 - 120 amps. Run DCEP or AC. Production size for flat work. If spatter increases above 108A, check your arc length.
3/32 (TIG) ER4047 Amperage
Set 3/32 (TIG) ER4047 to 100 - 180 amps. Run DCEP or AC. Largest available diameter. High deposition for flat and horizontal fillet welds on thick plate. Requires 100A minimum to run properly.
ER4047 Suitability Scores
How well this electrode matches common applications. Not a quality rating. all AWS-certified electrodes meet their specification.
What Is ER4047 Good For?
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.
Where ER4047 Falls Short
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.
Welding With ER4047
The Arc
Very smooth arc on TIG. The 12% silicon content drops the melting point even lower than ER4043, so the filler flows freely at lower amperages. On MIG, the arc is quiet and stable.
Technique
Same TIG and MIG technique as ER4043. The lower melting point means you can travel slightly faster or use slightly less amperage. The rod feeds into the puddle with less effort.
The Puddle
Extremely fluid puddle. The high silicon content makes the molten filler flow like water compared to ER4043 or ER5356. The bead wets out aggressively and fills gaps and tight joints easily.
When It Goes Wrong
If the bead is too wide and flat, you are running too hot for the material thickness. Reduce amperage. ER4047 flows so easily that it can spread beyond the joint if heat is too high.
ER4047 Size by Material Thickness
| Wire Size | Material Thickness | Application |
|---|---|---|
| 1/16" | 1/16" to 1/8" | Brazing and thin aluminum joints |
| 3/32" | 1/8" to 1/4" | Cast aluminum repair and fabrication |
| 1/8" | 1/4" and up | Heavier cast and wrought aluminum |
Shop Talk
ER4047 is the aluminum brazing and repair specialist. The 12% silicon drops the melting point below ER4043, making it ideal for filling gaps, repairing castings, and joining thin sections where heat control is critical. It produces the smoothest, shiniest beads of any aluminum filler. The trade-off is lower strength than both ER4043 and ER5356. Use it when fluidity and appearance matter more than load-bearing capacity.
Bottom Line
ER4047 earns its keep on repair jobs. It has no business on structural applications. The closest alternative is ER4043.
Setup & Safety Reference
How to Store ER4047
Store sealed. Same aluminum wire handling rules as ER4043.
Shielding Gas for ER4047
| Gas Mix | Common Name | When to Use |
|---|---|---|
| 100% Argon | Argon | Standard for MIG and TIG. |
| 75% Ar / 25% He | Ar/He | Better wetting and fluidity on castings. |
High-silicon aluminum wire. Pure argon standard. Helium helps with thick castings.
Preheat & Interpass Temperature for ER4047
Not required for thin sections. For material over 1/2 inch, preheat to 200-300F reduces porosity risk. Do not exceed 250F interpass on 5xxx-series base metals.
| Base Metal Thickness | Minimum Preheat (°F) |
|---|---|
| up to 1/2" | Not required |
| over 1/2" | 200°F |
Maximum interpass temperature: 250°F
Shielding gas flow rate: 25-35 CFH
Source: AWS D1.2, manufacturer data
Wire Feed Speed for ER4047
Requires spool gun or push-pull gun. Use 100% argon. ER4047 has higher silicon content than ER4043, giving better fluidity and wetting on thin aluminum.
| Diameter | Amperage | Wire Feed Speed (IPM) |
|---|---|---|
| 0.030" | 70-130A | 300-580 IPM |
| 0.035" | 90-170A | 250-480 IPM |
| .045" | 120-240A | 200-380 IPM |
Deposition Rates
| Diameter | Deposition Rate |
|---|---|
| 0.030" | 1-3 lbs/hr |
| 0.035" | 2-4 lbs/hr |
| .045" | 3-5 lbs/hr |
Fume Generation
Rating: Low
Typical fume rate: 0.1-0.3 g/min
Aluminum wire. Low fume. Same ozone considerations as other aluminum wires.
Common Brand Names for ER4047
Lincoln Electric SuperGlaze 4047 is the most common ER4047 on the shelf. 1 other manufacturers make the same classification.
| Manufacturer | Product Name | Notes |
|---|---|---|
| Lincoln Electric | SuperGlaze 4047 | |
| Harris | Harris 4047 |
Full Specs
| Property | Value |
|---|---|
| AWS Classification | ER4047 |
| Process | Aluminum MIG/TIG (GMAW) |
| Polarity | DCEP, AC |
| 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% Argon, 75% Ar / 25% He |
| Gas Flow Rate | 25-35 CFH |
| Max Interpass Temp | 250°F |
| AWS Specification | AWS A5.10/A5.10M:2021 |
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 38,000 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).
Where to Buy ER4047
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Manufacturer Data Sheets
External links to standards bodies and manufacturers. These leave GageRef.
Reference data only. Verify all settings against manufacturer documentation and the applicable welding code before use. Amperage ranges are starting points that vary by position, fit-up, and material. Welding involves serious injury risks including burns, electric shock, fume exposure, and fire. This site does not replace proper training, certification, or employer safety procedures. See full terms of use.
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.