What are rack marks/clamp marks and how will they affect my material?
Clamp marks on fabricated materials are inherent in the post-anodizing process and are essentially unavoidable. In order to maintain the proper flow of current, material is typically clamped in from the ends. This will leave marks on both sides of the material, usually about the size of a nickel or dime. When anodizing pre-formed parts, it is often possible to specify which area is the least exposed after installation and clamp accordingly. Sheets are typically clamped in the two adjacent corners of the length of the sheet. Material that is not excessively heavy may be racked using a pin clamp, resulting in marks that are considerably smaller than those caused by a normal clamping situation. All pre-finished anodized sheet under .125″ thick will have no exposed rack or clamp marks whatsoever. This is due to the fact that the material was anodized in coil form, rather than as individual sheets. Rack marks are also unavoidable on anodized extrusions, but on some shapes we can choose whic
