Materials
What filler wire or rod for mild steel?
Quick answer
For mild steel use ER70S-6 MIG wire, E48xx stick rods, ER70S-2 TIG rod. Matching filler to the parent grade is the rule — mismatched filler either cracks, corrodes or underperforms the base metal.
Filler selection
- Process choice: MIG or stick, gasless flux-core outdoors
- Filler: ER70S-6 MIG wire, E48xx stick rods, ER70S-2 TIG rod
- Prep: grind back to bright metal at least 20 mm each side of the joint
Why matching matters
Filler chemistry controls strength, corrosion behaviour and crack resistance. The classic Australian mistake is welding 316 stainless with 308 filler — it works, until the job sits in a coastal or chemical environment and the weld rusts first. When in doubt, weld with a filler at least as alloyed as the parent.