Cast iron

Insta-Blak 333 is an immersion/swab on blackening solution that results in a smooth, no-smut satin black finish on tools and architectural surfaces. One gallon of un-diluted Insta-Blak 333 concentrate can coat approximately 400–500 sq. ft. of metal parts.

Ultra-Blak 404 oxidizing salts are used to blacken cast iron, malleable iron, and some mild low-carbon steels with a deep, rich black finish.