Spec'ing a limit on Anodize Rack Marks

You will have to discuss, understand and finalize with your anodizer as to where the racking marks are acceptable on your articles. The racking has to be such that the articles do not loosen from the jigs during the entire process, from pretreatment to sealing. I am sure your anodizer should cooperate with you on this and rack the items in a manner that show very little marks.

Per MIL-A-8625

3.13.1 Contact marks. The size and number of contact marks shall be at a minimum consistent with good practice (see 6.14). If a specific location for contact marks is desired; the-location shall be specified-on the contract or
purchase order (see 6.2).

6.14 Size of contact marks. In order to obtain the desired current density without burning the parts, the size or number of contact marks will be greater on parts having higher surface areas. Because current density is a
measure of the required current per square foot of aluminum being anodized, a part having twice as much surface area relative to another will require twice as much current. Trying to force the higher currents required for larger parts through smaller contact areas sufficient for parts with lower surface areas may result In burning.