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Blackening Hot Dip Gal/Bright Zinc Parts

Q. Howdy,

I have a project coming up where I need to blacken/darken a large range of zinc-coated parts - I can either have them in hot dip gal, or bright zinc. Parts themselves are steel. They don't need to be particularly corrosion resistant or uniform, but all need to be black as it's part of a large exhibition piece. Paint isn't an option.

Previously I have removed zinc coatings with muriatic acid, then heated in a kiln + quenched in oil. I tried it without the muriatic acid step and it turned out garbage. It's worked fine, but for this job there's probably about 100 fasteners, around 50 large brackets and numerous other small parts, so it would be incredibly time/labour consuming.

Is there a chemical bath or easier process that would work? I've asked a local blacksmith, and he said the oil quench process was the only one he knew of. If it's anything that's less toxic that would be a great benefit.

Thanks

D Spriggs
- Brisbane QLD
June 25, 2024

Thanks - have read these and dozens of similar posts, and there has always been suggestions that things 'should' work but never any real confirmation that anybody had actually done it.

Unfortunately I can't order any of the parts in black chromate or this would make my life much easier.

Cheers

D Spriggs [returning]
- Brisbane QLD
June 27, 2024