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Mil Spec for hard anodizing
OK. I'm new to this Mil Spec for hard anodizing. It looks that type III is the most popular one. Does that mean there are type I and II? If they are, what's the difference among them? Also class means dyed or non-dyed, right? What kind of chemical they use for dyed? Only color is different between dyed or non-dyed? Or any chemical characteristic difference is there?Steve Lee
engineer - Placentia, California, USA
One thing you'll want to do, Steve, is get the spec you are talking about. I think you are referring to
Mil-A-8625 [link is to free spec spec at Defense Logistics Agency, dla.mil], which is available for free viewing or downloading at
Type I and II are types of anodizing, but they are not hard anodizing. Yes, Class refers to dyed or undyed, but as you will see in the spec, Class doesn't really apply to Type III coatings.
Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha
P.S. July 2013: This week the DLA site is at quicksearch.dla.mil