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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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Best way to color small metallic pieces
April 21, 2014
Q. So I've been asked for my graduation project to color small metallic pieces.
For this task I tried Electrocoating with an acrylic resin, electroplating and anodizing (where I thought firstly they were stainless steel but seeing how it reacted I quickly forgot about it).
None really gave me a good look on the pieces (treated 1 piece at time), so I am asking what is the best way to color small metallic pieces?
thanks
student - Korba, Tunisia
A. Hi Salem. You immediately discovered for yourself that before going any further it was essential to know what metal the pieces are made of. We are in that same position, so what metal are the pieces made of?
Millions of small pieces are electrocoated every day; and millions are electroplated, and millions are anodized -- but to date you have failed with these three. Millions of parts are also galvanized, powder coated, painted, patinated, electropolished, PVD coated, etc. But I don't think the proper lesson is to keep trying different technologies until you find one that works, but to figure out what you did wrong in what you tried. My first bet is that the parts weren't clean. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 2014
May 2, 2014
Q. As it seems, the pieces are made of copper coated in a thin layer of what seems chrome. The responsible that gave me these pieces doesn't know anymore as the pieces are subject to change depending on the supplier. So the ideal would be to find a process that will give satisfying results and doesn't depend that much on the metal to color.
E-coat or electroplating seems to be the best and easiest choices (since I can't do PVD).
I tried following the processes proposed by Dr. Goran Budija, using copper as anode, which seems to work on certain colors proposed but I fail to get all the colors proposed.
So the best thing now I can come with is to deposit a copper layer that would be colored next. Is this possible ?
student - Korba, Tunisia
A. Hi again Salem. Yes, it is possible to chemically patinate or to flame color a properly adhered high quality copper plating of sufficient thickness. But I don't know if you can achieve properly adhered high quality copper plating of sufficient thickness on an unknown substrate that already has some other unknown plating on it. After two postings I still don't know what your assignment is. Please post it because you're now saying you got certain colors by copper plating but you couldn't get other colors, and you want us to tell you how to get those unspecified colors.
And I don't understand what lesson the school is trying to teach you with this project. Do they also say that the "ideal" cake recipe would be one "that will give satisfying results and doesn't depend that much" on whether the unidentified powder you are asked to add is flour or white arsenic? :-)
Best of luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
May 2014
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