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Author: Subject: Anodizing dye
BeerChloride
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[*] posted on 23-11-2006 at 05:40
Anodizing dye


Hey folks, I'm looking for ideas on anodizing dye. The thing about aluminum anodizing seems to be the dying compound. The molecules need to be small and stable with light - therefore inorganic dyes.

Many general dyes such as "Rit", or "Dylon" (haven't seen Dylon here in the states), or FD&C #1, #5, #40 (food coloring) will work, but are probably not light-fast.

Aren't many "inorganic" dyes actually organic molecules? Anyway, I can't seem to find any msds info on the professional anodizing dyes. I saw somewhere that red "Kool-Aid" is actually an inorganic dye? If so, that would be a candidate. Any other suggestions would be much appreciated.:D

Edit: The FD&C #40 is an azo dye, which might explain the Kool-aid, and the fact that my anodizing test with it worked.

[Edited on 11/23/2006 by BeerChloride]
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enhzflep
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[*] posted on 23-11-2006 at 06:54


Well, to quote from a book I've here in front of me, (Jewelry Concepts and Technology - Oppi Untracht 1985 ISBN 0-7091-9616-4, in case anyone's interested)

"Several hundred transparent, specially manufactured proprietry organic dyes are available from suppliers for use in dyeing aluminium. However, organic dyes tend to break down upon exposure to sunlight. For greater light fastness, inorganic pigments such as yellow cadmium sulphide, violet gold chloride, or orange sodium molybdate are used"

......"Fading resistance is increased in proportion to the strength of the colour absorbed"

Furthermore, the dyebath should be setup as follows:
Water: deionised, pH 7
Dye Content: 0.025-1.0%
Temperature: 150 deg F (65 deg C)
Dye Tank: glass, stainless steel, plastic or fiber glass.

Later on the text mentions that generally, for most dyes the pH should sit somewhere in the range of 6 - 7. It recommends that a small amount of vinegar be used to lower the pH of neutral water.

Anyway, there's about three A4 pages on the topic. Going through the process from conception to the final polishing with a lime containing polishing compound. All temps, times, chems, current & voltage requirements are covered.
If anyone wants it, leave a post and I'll scan it in the morning.
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Hilski
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[*] posted on 23-11-2006 at 15:37


I always used Rit brand concentrated dye, and never had any problems at all. I mostly anodized things like small motorcycle parts and the like, for people locally and I never had any complaints about fading etc. I did sometimes apply a clear coat after the part had been cooled and dried completely, depending on what the part was going to be used for.
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BeerChloride
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[*] posted on 23-11-2006 at 17:41


Thanks for the good info, guys. Enhzflep, I'm not sure I need those details at this point. Maybe at a later point I might try to ultra-fine-tune a process, though.

P.S.: Does anyone have any thoughts on trying something like an ammonia-complexed copper salt? (probably won't come out very dark, though).

[Edited on 11/24/2006 by BeerChloride]
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