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Hard Coat Anodize Clear, FDA

Q. My company manufactures a product that bags ice and the unit was not designed by my company. Two of the parts have finish specifications of, "Hard Coat Anodize, Clear, FDA." There is no reference to thickness and I cannot find the FDA specification for hard coat anodize. Is there a non-destructive way to verify this finish along with the thickness so I at least can have a record that it was checked?

Richard Webb
Comercial Metal Fabrication - Elk Grove Village, Illinois ,USA

A. Most likely, this is a hard anodize per MIL-A-8625 / MIL-PRF-8625 [on DLA] type III class 1 (undyed) either unsealed or sealed in boiling DI water... however, the only way to be certain is to ask the person that did the original anodize.

In terms of verifying, first download a copy of the above specification (there are links to the ASSIST website from the homepage of, then use their search engine) so you know what the requirements are. Then, either obtain certification from the anodizer or purchase a handheld thickness tester and verify the coating thickness.

The only way to non-destructively verify the type of seal used (if used - by default it won't be, but it may be necessary for the FDA regulations; I'm not certain) is to ask the anodizer. To learn more about anodizing and the FDA, use the search engine on this website to check some of the archived letters - at least one has a copy of an FDA letter basically stating that clear anodize is grandfathered in (if I recall correctly).

Good luck!

Jim Gorsich
Compton, California, USA

Ed. note: Thanks Jim. The URL of the ASSIST site keeps changing, so rather than having to keep revising it here and on hundreds of other pages, we keep the URL up to date on our "Mil Specs FAQ" page. The copy of the FDA letter can be viewed here.

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