How Is Steel Blackened For External Uses?

Blacken steel is a popular choice for interior and exterior design due to its sleek, industrial look and ability to create a striking contrast with lighter materials. There are various methods to darken and become water-resistant, including hot blackening, cold blackening, wax and oil, mid-temperature blackening, and painted products.

Oxidizing steel is a process that achieves a blackened effect on steel, giving it a unique appearance and protection against corrosion. This can be achieved by dipping the steel in a heated chemical bath, which can develop a deep black oxide over the surface of the steel. Galvanized (Zinc Coated) steel sheets are most often required for exterior applications of this decorative finish. Blackening agents will darken the zinc, not the steel.

Mild steel blackening involves treating the surface of the mild steel with chemicals to create a dark, protective coating. Room temperature blackening for iron and steel (Presto Black®) and stainless steel (Presto Black® SSB) utilizes copper/selenium chemistry without heat and forms a black conversion coating.

To prepare metal, use acetone and a clean rag to wipe off excess oil, rust, etc. from metal parts. Mechanical finishes, such as grinding, sanding, or polishing, may be necessary to smooth the steel surface before blackening. A mixture of meths or turpentine, tannic acid, and a drop of oil can be applied with a brush when hot, giving a matt rich black/brown finish. SteelAge offers a more controllable and robust alternative to chemical blackening for your project.