How to Weld Corten Steel: Methods and Filler Materials
Corten steel is weldable using standard methods (MIG, TIG, stick) but requires specific filler materials to maintain weathering resistance at the joint. Using ordinary mild steel filler creates a weak point that rusts faster than the parent material.
Recommended welding methods
| Method | Best For | Filler Wire/Rod |
|---|---|---|
| MIG (GMAW) | Production welding, planters, edging | ER80S-G or Cor-Match 80-CW |
| TIG (GTAW) | Thin material, visible joints | ER80S-G |
| Stick (SMAW) | Field repairs, thick sections | E8018-C3 or Cor-Match 810W |
Key rules for welding corten
- Use weathering-grade filler: The filler must contain copper, chromium and nickel to match the parent metal’s corrosion resistance.
- No preheating needed: For material under 12mm, preheating is generally not required. Above 12mm or in cold conditions (below 5°C), preheat to 50–100°C.
- Grind mill scale: Remove 25mm of mill scale from each side of the joint before welding for proper fusion.
- Continuous welds: Avoid skip welding on planters and water-holding products. Continuous seams prevent water ingress at gaps.
- Post-weld: Do not paint the weld. Allow it to weather naturally with the parent material. The weld will initially look different but blends within 3–6 months.
For fabrication specifications on our products, see our planter fabrication details or contact our engineering team for welding procedure specifications (WPS) for your project.
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