Pre chemical finishing or anodizing
Mechanical finishing, if specified, is done before chemical finishing or anodizing. Mechanical finishes give surface texture or remove surface defects and irregularities. Appearance can be varied but usually gives a uniform, matte finish, directional or nondirectional-sanded finish, or a specular (mirror-like) finish. The mechanical finish shows through the anodic oxides because uncolored anodic oxides are transparent or translucent and anodic oxides conform to the surface texture. This means that surface defects, as well as applied surface textures, are not covered up by anodizing. Examples of mechanical finishes are buffing, polishing, sanding, sand blasting, and shot peening. Refer to the appendix for specific designations of mechanical finishes.