Metal finishing Q&As since 1989

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Colorfastness Issues with Red Anodized Aluminum Flashlight Bodies

April 20, 2008

I am dealing with my first issue dealing with anodized parts. I have an anodized aluminum flashlight body that is failing the colorfastness test required by one of our large customers. The sub-contractor(s) that I am using for my parts both seem unable to indentify the root cause of the problem, so I am attempting to reseach and find the soultion myself.

Questions:

1. My customer is requiring that the anodized surface maintain a rating of 3.0 after 100 hrs exposure to a Xenon Arc Lamp, per the AATTC requirements. My parts are testing at between 1.5 - 2.0 at the current time. What are the most influential factors that I should begin to look at?

2. How do I confirm the type of anodizing that my subcontracctor is using?

3. Which type of dye is most suitable?

4. Are certain colors more likely to fade than others?

5. Can I have a chemical analysis performed to find the root cause of the issue that I am experiencing?

6. Can additives be introduced into the dye to increase the colors ability to better withstand UV exposure?

7. How can I confirm the quality and integrity of the sealing process after the dye has been applied?

Jim Moore
Product Designer- Las Vegas, Nevada, USA

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First let's do an ASTM Seal test. Some reds are very difficult to seal. Many job shps do not even begin to control their seal.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

April 22, 2008