Need info re: Changes is RMS Values after Hardcoat Anodize  

Letter 10084

I am looking for data regarding Hardcoating Aluminum & the change in RMS values that should be expected after finishing.

David A. Kraft Anacote Corporation Long Island City, NY

See Hard Anodizing of Aircraft Fuel Metering Components, Wiesner and Meers, 45th Annual Technical Proceedings, AES, 1958, for Martin Hard Coat reference which states that for cast alloys like 355 and 356, silicon particles cause irregularities, making it difficult to obtain 10 RMS.

Tom Pullizzi platronica.com Falls Township, PA