Kansas City Star Production Facility
The production facility for the Kansas City Star includes a locally manufactured, custom-patinated copper, created by Zahner for the building's facade. The new production facility for the Kansas City Star was designed and developed by The Austin Company, an engineering design firm specializing in large-scale industrial facilities.
Zahner developed a preweathered copper patination system for this building. An estimated 4155 pre-patina copper panels were installed on the building's surface to create the 80,000 SF surface area. The building's green surface is mottled and variegated, a patina designed to age the building's copper surface by 200 years. The natural patina will continue to grow and change in appearance as it ages. The patina provides a layer of natural protection for the copper alloy.
Custom Patinated Copper
Copper alloys, whether they are prepatinated or not, will continue to transform as the surfaces age. This happens more rapidly when exposed to moisture, sun, and pollutants. Over time, this transformation will occur at a progressively slower rate as the copper surface reaches a chemical equilibrium. For example, bronze statues, exposed to the weather for centuries, often develop a darkish "bloom" in the form of a spot or streak. These localized changes are the product of natural pollutants and the further aging of the surface.The predominant oxide to develop on the surface of copper alloys exposed to the atmosphere is cuprous oxide, Cu2O. This oxide is essentially the mineral cuprite. The color is reddish brown, but often exhibits a range of color from orange to yellow, even purples, as can be seen in the Dirty Penny copper material developed by Zahner. The minerals of copper undergo a very slow aging process, though the process is somewhat faster when near the sea. Another somewhat common mineral formation on copper alloys combines carbon dioxide and forms carbonates over the initial cuprous oxide layer. The carbonate mineral forms are malachite and azurite. These relatively uniform corrosion products are difficult to artificially create.All copper and copper alloy surfaces exposed to the atmosphere undergo changes. On a molecular level they seek various compounds from the atmosphere and readily combine with them. They actually remove pollutants from the air, albeit very slowly, by combining with sulfur dioxide and carbon monoxide to form mineral compounds that effectively trap the pollutants.