Where theworld gathers for metal finishing
Q&As since 1989
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Castings and Black Anodizing Color
Q. Hello,
I am searching for a metal finishing process for an aluminum investment casting, which will match the cosmetics and durability provided by black anodizing aluminum bar stock and aluminum extrusions.
Sincerely,
Charlie Dekar- MDR Co.
1998
A. Do you want a substitute for black anodizing? I would think that the cost of your casting would justify the cost of anodizing it.
My apology if I misunderstand your question.
Tom Pullizzi
Falls Township, Pennsylvania
1997
Q. We are continuously trying to get our castings (usually diecast) a deeper and more uniform black color. We would appreciate any suggestions including bath parameters, pretreatment methods, etc., that give us the best color. Thank you in advance.
Tim Neth
Mr Tim Neth- Batavia, New York
2000
A. The problem with casting material is that there is no real deep black color possible as with wrought materials. In rare instances I have been capable of getting casting material almost as dark as wrought, but its just not easily possible. This has to do with the porosity of the cast material and various other elements. You could try increasing the thickness of the anodize to see if this helps the situation, but odds are you'll find that its just not going to satisfy you in the end.
I wish I could give you the answer you wanted to hear, but its just not possible from my experience, if someone out there knows how I'd be interested in what you do to make this happen.
Matthew Stiltner- Toledo, Ohio
2000
A. Hi
I have used Kal-gard (gun coating) on castings and the process is very durable and corrosive resistant. you spray it on the raw casting and then bake the component at 200 °C for about 1 hour. The color quality is very good.
There are various grades of coatings and some are even better protection than anodizing. See the specs.
Michael Georgiadis- South Africa
2000
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