Hand-rubbed finishes are produced by rubbing with No. Uniform finishes are less expensive than satin finishes and are suitable for many architectural applications.

Uniform, a cost-effective finish produced by a single pass of a No. Directionally textured example: C11000, brush finished. Final grits range from 240 mesh to 320 mesh for fine satin and 80 mesh for coarse satin.įigure 3.1C. The six standard directionally textured finishes are:įine, medium and coarse satin, which reflect the coarseness of the final polishing abrasive. Their smooth, satin sheen is produced by wheel- or belt-polishing with fine abrasives that leave closely spaced, nearly parallel scratches. These finishes are the most frequently used mechanical treatments for architectural copper metals. Field repair is possible but expensive, since it involves extensive hand operations. Surfaces may contain minor scratches and imperfections. It is also produced by polishing and buffing, but to a lesser extent than that for smooth specular. Specular is a somewhat less-bright surface. It is especially important to protect smooth specular finishes during installation because they are challenging to apply or touch-up once installed. This is the most costly mechanical finish applied to copper metals. Smooth specular, a very bright, mirror-like surface produced by abrasive belt-grinding followed by polishing with progressively finer abrasives and buffing with extremely fine compounds. The two subclassifications of buffed finishes are: Polished and buffed finishes on interior surfaces are often protected from tarnishing using lacquers. Their high reflectivity imparts a tendency to reveal even slight distortions and lack of flatness. They are frequently used for hardware and small decorative objects. Their relatively high cost reflects the added value of preparation. Produced by sequential grinding, polishing and buffing operations, polished and buffed are extremely smooth and bright. The specular or mirror finish on this facade reflects the colors and images of its environment. As-fabricated finishes include:įigure 3.1B. Rolled finishes, for example, will replicate the surface of the final roll in the mill, and as-cast surfaces will betray the nature of the foundry method employed. They can also vary in appearance, both intentionally and accidentally. The term “mill finish” is commonly used for an “as fabricated” finish.Īs-fabricated finishes can be marred by secondary operations such as bending, milling and welding, in which case, they may require additional finishing operations. They are the least expensive finishes, and, while they may contain imperfections, they are uniform enough with sheet goods for applications such as roofing and wall cladding. These finishes are the mechanical surface conditions resulting from primary production processes, e.g., hot and cold rolling, extrusion, drawing and casting. As examples, buffing and grinding are mechanical operations whereas, oxidizing and patinating are chemical in nature. Mechanical finishes are imparted by physical rather than chemical means. Use the alpha-numeric codes in Tables 3.7B, 3.7C and 3.7D to specify these finishes. The following paragraphs, abstracted from the NAAMM/NOMMA Manual, describe these and a few other finishes. There are four recognized classes of finishes for copper alloys: mechanical, chemical, protective coatings and laminated finishes. Choice of worksite is normally reserved for the fabricator with consent of the architect. 1įield application is occasionally necessary for colored or oxidized finishes and for items such as large immobile statuary. In order to systematize this colorful collection and provide a basis for specification, the National Association of Architectural Metal Manufacturers (NAAMM) and the National Ornamental & Miscellaneous Metals Association (NOMMA) describe frequently used finishes in the Metal Finishes Manual for Architectural and Metal Products. The wide variety of textures and colors available with copper alloys provide architects with an almost limitless palette of visual effects. This lobby in Anchorage, Alaska, artfully displays panels of copper alloys using a variety of colorful chemical and mechanical finishes.

Patina aluminum coating