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Bluing

Home > Modern Firearms Manufacture > Cosmetic Finish > Bluing
Metal that has been through the bluing process with scratches to see the bare metal underneath

Bluing is about 2 millionths of an inch thick.
A knife test easily scratches the surface,
revealing the bare metal beneath.

Photo Courtesy of Evolution Gun Works, Inc.

Bluing is used on steel metal parts to provide a protective coating. This involves an oxidizing chemical process that provides some protection against corrosion. Depending on the specific process, the resulting coating appears as a blue or blue-black color on the metal exterior.

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