The BK-LC Mini Lumiclad line from Birchwood Casey is designed to enable in-house blackening of small lots of aluminum parts. The blackening process uses a simple dip-tank procedure to form a durable black-oxide coating that adheres to the aluminum substrate with no rub-off. Unlike conventional black anodizing, it uses a single, heated tank and does not require electrolytic current.
At 1.5 microns thick, the Lumiclad finish will not shrink hole diameters or add measurable thickness, the company says. Part dimensions also are maintained without requiring critical surfaces to be undersized to allow for excessively thick coatings.
The process is said to work well on virtually all cast- and wrought-aluminum alloys. Designed primarily for indoor applications, it is especially suited for pistons, valves, machine components, tooling, fixturing or other precision-machined components. Using baskets or rotating barrels, it can blacken small parts in bulk loads that are uneconomical to anodize, such as fasteners, screw machine parts and stampings, and other low-value parts