EPi is the only supplier to offer all three types of metal blackeners, which are differentiated by the temperature at which the solution will properly blacken a part.

Black Oxide is a blend of caustic oxidizers and additives that are used to blacken ferrous metals. The black-oxide coating is produced by a chemical reaction.

The result is the formation of black oxide on the surface of the metal being coated. In-house metal blackening offers a variety of advantages, including:

  • Dimensional stability
  • Anti-galling properties
  • Smut-free, deep black finishes
  • Aesthetic appeal

Hot-temperature black oxide (285 F°) is a conventional hot process which produces a true black oxide iron magnetite (Fe3O4) finish. It is a premium-grade salt mixture which will blacken a wider range of steel alloys than any other process on the market.

Select a hot black-oxide process to:

  • Blacken parts in 10–20 minutes
  • Produce a glossy blue-black color
  • Create impressive abrasion and corrosion resistance
  • Finish hard-to-blacken metals 5–10 minutes faster
  • Produce no dimensional change
  • Generate less sludge
  • Blacken without baking, excessive handling, or producing volatile fumes
  • Save money thanks to a low product-to-water ratio
  • Work with cadmium, cast ironstainless steelsteel, and zinc

Featured products: Ultra-Blak 400, Ultra-Blak 455, Ultra-Blak 420


Mid-temperature black oxide (225–255 F°) is the latest development in blackening processes, producing a true black oxide iron magnetite (Fe3O4) finish. It produces no caustic boiling fumes and provides a safer working environment.

Select a mid-temperature process to:

  • Blacken metals in 30–45 minutes
  • Produce glossy black appearances
  • Achieve a uniform finish
  • Create smut-free, abrasion-resistant finishes
  • Blacken in a variety of methods
  • Save energy in heating costs
  • Pass oxalic acid military tests
  • Create safer working environments
  • Blacken steel, zinc, and copper-brass-bronze

Featured products: Kool-Blak 225


Room-temperature black oxide (65–85° F) is the preferred metal-blackening process for safe and convenient in-house blackening. It is an excellent non-bleed black finish for powdered metal and cast iron. It produces super deep blackness and corrosion resistance equal to hot oxide blackeners.

Select a room-temperature process to:

  • Blacken parts in 1–5 minutes
  • Produce grey-black satin finishes
  • Resist corrosion
  • Blacken cast iron, forged steel, tools, or powdered metals
  • Save money in heating costs
  • Produce no discharge and remain environmentally friendly
  • Avoid generating hazardous waste
  • Work with selenium compounds, rather than a true black oxide
  • Blacken aluminum, cadmium, cast iron, stainless steelsteel, zinc, and nickel

Featured products: Insta-Blak 333, Insta-Blak 333 GEL, Insta-Blak A-380