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Anodize Seal quality test

 

Hi,

Could you please specify how to do seal quality test with ink for chromic anodize coating?

Owen Y. Liao
- Barrie, On., Canada

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British Standard 3987:1974, anodic oxide coatings on wrought aluminum for external Architectural applications is a test, sorry, I don't see the use of ink anywhere, and it might be for sulfuric anodized parts, but I gave it a try.

  
Tom Pullizzi
Falls Township, Pennsylvania

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The "stain resistance test" as we call it can be found in detail in the ASTM document titled ASTM B136 [affil link] "Measurement of stain resistance of anodic coatings-test method" Your local Document center should have this. Basically a 50% nitric acid is applied to a small area (drop or two) of the part and left on for 6 minutes after which it is wiped with a clean damp cloth. A Blue dye is then applied for a particular period and after wiping again no absorption of the dye should have occurred. This test should not be used for 2000 series alloys containing high 4% copper.

Good luck.

Bill Grayson
- Santa Cruz, California, USA