Where the
world gathers for metal finishing
Q&As since 1989


-----

Scratches on anodized aluminum "definition"

Hello, I have a problem with operators kicking out parts because there's what seems to them to be scratches on the surface. The part is aluminum and after anodizing and duplex sealing it the part turns a yellowish green color. The part if you hold it to the light you could see a very small gleam of silver, it is not what I would call a scratch but I want to be sure. Is there any definition for scraches on anodized parts, some constant I could use to train operators and inspectors on what's acceptable and what's not. Thank you.

Derek Heppding
quality foreman, finishing supervisor - Scranton, Pennsylvania, USA
2007

---

There are published causes for defects, and recent letter 45917 was about that. But as for aesthetic standards of acceptability, you won't find anything. What you probably need to do, unscientific as it sounds, is set up a "sample board" showing what is acceptable and what is not.

There will be small non anodized "rack marks" where the current entered the parts, but pending hearing from someone else, I don't think you should see a silver color elsewhere.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007