Summary for anodized parts between dyeing Discussion
The thread asks where to keep racks of parts after anodizing but before dyeing. Robert H Probert advises that, after coming out of the anodizing rinse, the waiting racks can be stored in 5% by volume nitric acid, with the caution that there must be no chloride impurities present. When it is time to dye, he says to rinse the parts again in a different tank and then proceed to dyeing. Marc Green offers a simpler alternative, suggesting cold water. The discussion is brief and presents two different approaches, with Probert’s answer giving the more specific storage recommendation and Green’s comment indicating that cold water may also be used.
RECOMMENDED ANODIZING & CHROMATING BOOKS
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“The Surface Treatment & Finishing of Aluminium and Its Alloys” by Wernick, Pinner & Sheasby (1959 – 2001)
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“The Metallurgy of Anodizing Aluminum” by Jude Mary Runge (2018)
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“Surface Treatment and Finishing of Aluminum” by Robert King (1988)
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“Anodic Oxidation of Aluminum and Its Alloys” by V. F. Henley (1982)
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“Aluminum Finishes Process Manual” by Reynolds Aluminum (1973)
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Q. WE ANODIZE COSMETIC PARTS.WE ANODIZE AT ONE TIME 12 RACKS.FROM THE FIRST RACK I DYE TO THE LAST ONE IT TAKES ABOUT 60 MINUTES AND WE HAVE SOME COLOR VARIATIONS. WHERE SHOULD WE KEEP THE ANODIZING RACKS WHILE THEY ARE WAITING FOR THE DYE BATH? WE NOW KEEP THEM AT THE ANODIZING TANK BUT I THINK THERE SHOULD BE ANOTHER SOLUTION THAT WOULD WORK BETTER.
Ricardo Brakarz
metal forming – Rio de Janeiro, Brazil
2004
 | A. Coming out of the anodizing rinse one time. Then store the waiting racks in 5%/vol Nitric Acid (be sure there is no chloride impurities hanging around). When ready to dye, rinse again in a different tank and dye.
2004 A. I would not make this a standard practice, dyeing should commence immediately after anodizing, and thorough rinsing. You are opening up a myriad of possible problems by waiting, with contamination, or the possibility of the coating beginning to self-seal, and not accepting the dye. Its quite obvious why you are having discoloration/consistency problems if you are leaving your parts set in the anodizing tank for an extended period of time while waiting to put them in the dye.
A. TRY COLD WATER
2004 |
A. I think I misunderstood. I thought you wanted to store the parts overnight, or for a long period of time. I’d go with Roberts idea.
Marc Green
anodizer – Boise, Idaho
2004
THANK YOU !
Ricardo Brakarz [returning]
– Rio de Janeiro
2004
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