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About Black Oxide

Black Oxide Finishes Are Used When a Long-Lasting, Durable Protective Black Coating is Required

Since 1939, Du-Lite has been a leading supplier of black oxide finishing equipment, chemicals, and accessory products to American and foreign manufacturers. Originally developed to replace highly poisonous cyanide methods of "bluing", our Steelkote™ process does not contain cyanide, mercury or heavy metals which are detrimental to the environment or a health hazard for the operator. An important part of our success has been the technical support we provide to our customers. We maintain a complete lab facility to assist customers in solving their most difficult black oxide problems. Technicians are available to answer questions from the field. We also maintain our own black oxide production facility, which is used to test sample parts. This allows proper recommendation of equipment and chemicals to prospective users.

What is Black Oxide Finishing?

Du-Lite's black oxide is a chemical blackening process for carbon steel parts. Du-Lite provides other chemical processes to blacken stainless steel, silver solder, cast iron, brass or copper. The black oxide process actually penetrates the metal surface to provide durable protection without altering the physical dimensions or properties of the metal itself.

Who Uses Black Oxide Finishing?

For many years, manufactuers of firearms, auto parts, turbines, bearings and electrical parts, along with tool and machinery builders have relied on Du-Lite for superior parts finishing. Du-Lite provides black oxide and protective oil products to 70% of the American firearms industry.

How Is Black Oxide Applied?

The black oxide process is produced from a specially developed alkaline nitrate solution which is heated to 285° F, producing the most durable black oxide finish available. The process consists of five steps.

  1. Alkakaline Soak Cleaner
  2. Warm Water Rinse
  3. Hot Black Oxide
  4. Cold Water Rinse
  5. Water Displacing Oil

How Do You Start With a Black Oxide System?

The first step to building a black oxide finishing system is to establish the necessary tank size to process your largest part. Also important to consider is the composition of your steel (mild, hardened, stainless, etc.). The composition will determine the make-up of your line.

Du-Lite provides entire systems or modifications to existing facilities. We will consider many factors to determine the precise system that best fits your needs and budget.