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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing 1989-2024
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Problem dying anodized aluminum green
Q. Good day.
I am having some challenges with the green dye in my anodizing plant and am hoping that someone can assist.
I have 9 colours set up for anodizing and have just recently set up a green dye tank. It seems as though the green may be temperamental.
In all my colours I get a build up of algae after some time which i effectively filter out and continue with the the process with good results. All the dye colours I use are supplied from Macdermid.
I have had problems with the green from set up where the part comes out of the dye tank with dark spots on it and once wiped down leaves spots of very lightly dyed areas. I have filtered the dye out of the dye tank into another tank and back again, a number of times. Even going down to a 1µm filter I am not able to correct the effect I am getting.
I am running the tank at 10 gr dye to 1 L deionized water, heated at 60 °C and a PH of 5.5
I am at a loss with the green dye and am hoping that someone has a working solution for me to try.
- South Africa
October 11, 2024
A. Hi Denvor
I personally have never heard of anything special about green aluminum anodizing dye as compared to any other color which would make it more difficult or problematic.
But I have heard of bad batches of dye. If you have any of the dye left that has not yet been put into the line, you could put some in a large beaker on a hot plate and see how it performs on coupons. If it doesn't work there either, I'd certainly suspect that it was defective. If it does work fine, perhaps your 1 µm filter captures something in green dye which isn't in the other dyes ... but it would surprise me.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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