Anodize Coatings for Aluminum Alloys

purple anodize aluminum partMore recently, we have been seeing manufacturing prints that call-out an incorrect military spec for anodize on aluminum parts. As a result, we wanted to do this blog post to better inform engineers of calling-out the right classifications for anodize. But first, here is a mistake we have recently seen that is a good example:

Incorrect: “Finish: Anodize MIL-A-8625 Type II, Class 1, Blue”

The issue with this incorrect call-out is the class number and color. According to Military Spec MIL-A-8625, Class 1 is designated as “non-dyed.” This contradicts the “blue” color that is called out. All Class 1 specifications need to be clear color. To designate a color (blue, black, etc.), Class 2 needs to be specified. Here is the proper way to call out the specification above (please note the following call-outs are an example pertaining to the incorrect call-out above. Call-outs can vary depending on the desired Type/Class/Color): Continue reading