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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Purple type 2 anodizing trouble
Q. Hello, I have a machine shop and a small anodizing line with 30 gallon tanks. We have been anodizing for about 5 years and purple is the only color I can't seem to perfect.
We are using the Violet from US Specialty and we have tried just about everything from different dye temps to longer anodize times. We always seem to lose a shade when we seal it and it was suggested that we raise the dye temp to 160 °F so it will seal and dye at the same time but it's inconsistent. The purple shade just seems light even when we polish it to a mirror finish. The pH in the dye is correct and regardless of how long we soak it, the color just won't get darker. We have also made several batches of dye with the same results. None of our other colors fade and this is kicking our butts. If you have any advice we would really appreciate it.
Todd Brueckmann- Aylett Virginia
April 27, 2021
A. Todd
Violet isn't really a pastel color so thin coatings won't absorb enough dye to yield a deep rich color. Try a thicker coating, say .6 - .8 mils thick if you're not already at that thickness.
- Green Mountain Falls, Colorado
April 28, 2021
I will give that a shot. Appreciate the feedback!
- Aylett Virginia
April 29, 2021
A. It is possible you are not putting enough oxide on the parts. Check the thickness. I think you may be light, I would make sure you are getting 6-8 tenths on the parts. If so, build up the thickness to over 8 and see if that makes a difference.
Drew Nosti, CEF
Anodize USA
Ladson, South Carolina
May 5, 2021
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