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3D Printed Aluminum Won't Anodize Black
Q. I am developing an anodizing process for 3D-printed aluminum. So far, I have experimented with different material preparations (blasting), anodizing times, voltages and dye bath concentration . However, the parts are not turning out truly black -- they appear either flat or gray. What other parameters should I be focusing on to achieve a deeper black finish?
Jokim BaskaranChemist - Reading, Pennsylvania
September 8, 2025
A. Hi Jokim,
Interesting question. Apparently either the anodizing is not thick enough, or is distorted in some way which is preventing proper absorption of the black dye. Can you tell us the thickness of the anodizing ... because it is difficult to get a good black without 0.005" thickness or more.
I suppose another possibility is that the topology of the surface of the 3-D generated aluminum is weird in some fashion, which make the part look gray instead of black, but I personally haven't heard of such a thing. Can you tell us anything about the surface finish?
Finally, have you attempted to dye these 3-D parts any other color. And. if so, can you report on any ideosyncrocies noted in the anodizing, dyeing, or sealing which might give us additional hints?
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Ted can be retained for immediate
answers or long term project help
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