High-Silicon Brazing Wire vs Standard Aluminum Filler
ER4047 with 12% silicon for brazing and castings vs ER4043 with 5% silicon for general aluminum welding.
Key Differences
| Attribute | ER4047 | ER4043 |
|---|---|---|
| Silicon Content | ~12% | ~5% |
| Melting Range | 1070-1080F (lowest) | 1065-1170F |
| Fluidity | Maximum - flows into tight joints | Good - standard flow |
| Tensile Strength | 28,000 psi | 33,000 psi |
| Crack Resistance | Excellent - high Si prevents cracking | Good |
| Anodizing | Not anodizable (turns dark) | Limited color match when anodized |
| Best Application | Brazing, castings, thin sheet | General 6xxx series welding |
| Availability | Specialty - less common | Very common - widely stocked |
Use ER4047 when:
Use ER4043 when:
How ER4047 and ER4043 Work Together
ER4043 is the default aluminum filler for 6xxx series alloys. ER4047 is specialized for brazing, casting repair, and applications where maximum fluidity and minimum cracking are needed. The higher silicon in ER4047 lowers the melting point and makes the weld pool flow into tight joints. If you are welding standard 6061 aluminum with TIG or MIG, use ER4043. If you are brazing aluminum, welding castings, or working with very thin material, ER4047 may produce better results.
Common Mistake With High-Silicon Brazing Wire
Using ER4047 for structural aluminum welding expecting higher strength. ER4047 is weaker than ER4043 (28 ksi vs 33 ksi tensile). Its advantage is fluidity and crack resistance, not strength. For structural aluminum, ER4043 or ER5356 is correct.
Where to Buy
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Data sourced from .