Material guide
Welding Galvanised Steel: Fume Safety and Practical Settings
Galvanised steel welds fine — it's the zinc smoke that bites. Grind the coating back where you can, ventilate like you mean it, and know the flu-like symptoms of fume fever.
Process and filler selection
Default process: flux-core or stick 6013/7018 on it, MIG if you grind the coating back. Filler: same as mild steel; silicon-rich wires handle zinc slightly better.
Preparation
Grind the gal off the weld zone where you can — it's faster than fighting porosity. Fit-up matters more than settings: gaps eat filler and heat control at exactly the wrong moment.
Heat management
Zinc fume causes metal fume fever ('welders' flu') — ventilation or a fresh-air mask is non-negotiable under as 1674
Fume safety first
Zinc oxide fume causes metal fume fever — fever, chills and aches hours after welding. It passes, but it's a documented hazard and repeated exposure isn't something to shrug off. Grind the gal off the weld zone where practical (the cheapest control), use real extraction or cross-ventilation, and wear a P2 respirator. And no — milk does nothing; that's a myth we bury properly in our safety Q&A.
Settings and process
Expect more spatter and some porosity fighting the zinc: bump amps slightly, drag slightly, and let the anti-spatter spray earn its keep. Flux-core and stick tolerate the coating better than gas MIG. Post-weld, the burned zone loses its corrosion protection — brush, degrease and re-coat with a zinc-rich primer or the rust starts there first.
Frequently asked questions
Can you weld aluminium with a MIG welder?
Yes, with two conditions: the machine supports a spool gun or has an aluminium-capable drive, and you use 100% argon with aluminium wire (ER4043 or ER5356). Soft aluminium wire jams in long conventional MIG torch liners — that's what the spool gun solves. Thickness under ~1.6 mm belongs on TIG.
How to weld mild steel
To weld mild steel: use MIG or stick, gasless flux-core outdoors, filler matched to the parent metal (ER70S-6 MIG wire, E48xx stick rods, ER70S-2 TIG rod), and prepare properly — grind back to bright metal at least 20 mm each side of the joint. The key adjustment vs mild steel: baseline (40 A/mm MIG rule).
What filler wire or rod for mild steel?
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.
Best welding process for mild steel?
The best process for mild steel is MIG or stick, gasless flux-core outdoors — chosen for how the metal conducts heat and what contamination costs you.
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