Three Mini Metal Finishing Systems

July 01, 2015

Birchwood Technologies offers three mini systems for use in small batch metal finishing at low temperatures. Mini systems are perfect for manufacturers looking to add in house capabilities but do not have the necessary volume or space for a full sized process line. Birchwood Technologies offers these uniquely versatile blackening solutions for the Presto Black and TruTemp processes for iron and steel parts, and the Lumiclad process for aluminum parts.

The cold PRESTO BLACK process forms a non-dimensional coating thickness of less than 0.5µm thickness and is ideally suited for components that require a black finish for visual appeal. PRESTO BLACK is a short fifteen-minute process that provides high corrosion resistance and is tested for up to 800 hours humidity exposure when sealed with an appropriate rust preventive. The PRESTO BLACK process offers a friable crystal structure that serves as a sacrificial barrier on sliding surfaces to protect the underlying steel itself from galling and deformation.

The low temperature TRU TEMP process forms a durable satin black magnetite coating, 0.5µm thick, with no effect on material hardness or tensile strength. The sealed finish withstands up to 100 hours of neutral salt spray or several hundred hours of humidity, and protects the metal surface during shipment and storage as well as in service. TRU TEMP black oxide operates effectively with alkaline chemistry that does not embrittle metal or create unsightly salt bloom in and around recessed part areas.

The LUMICLAD process forms a non-dimensional black oxide finish on all aluminum surfaces that is durable, clean and tightly adherent to the metal substrate. The LUMICLAD process develops a uniform coating thickness of 1.5µm that will not close down hole diameters or change critical part dimensions. The smooth black finish has a slightly porous crystal structure that absorbs an optional topcoat such as a dry-to-touch sealant, light oil, or clear polymer.

All three processes utilize a conventional seven-tank immersion process line, and operate at low or room temperature, making the processes easy and safe to operate in-house. Mini systems are perfect for short run sporadic production because the lines can be sealed and stored, with the chemicals in the buckets, for six to twelve months.

Related Glossary Terms

  • black oxide

    black oxide

    Black finish on a metal produced by immersing it in hot oxidizing salts or salt solutions.

  • corrosion resistance

    corrosion resistance

    Ability of an alloy or material to withstand rust and corrosion. These are properties fostered by nickel and chromium in alloys such as stainless steel.

  • galling


    Condition whereby excessive friction between high spots results in localized welding with subsequent spalling and further roughening of the rubbing surface(s) of one or both of two mating parts.

  • hardness


    Hardness is a measure of the resistance of a material to surface indentation or abrasion. There is no absolute scale for hardness. In order to express hardness quantitatively, each type of test has its own scale, which defines hardness. Indentation hardness obtained through static methods is measured by Brinell, Rockwell, Vickers and Knoop tests. Hardness without indentation is measured by a dynamic method, known as the Scleroscope test.

  • tensile strength

    tensile strength

    In tensile testing, the ratio of maximum load to original cross-sectional area. Also called ultimate strength. Compare with yield strength.


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