Metal finishing Q&As since 1989

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How to get Satin Matte finish for Anodizing

June 28, 2008

We are an aluminium anodizing company in India. We are getting inquiries for satin matte finish anodizing. They have produced samples which have dots like finish or you can say small crystals are over the surface. The people wants the same finish. Actually after etching for some longer time we get that finish. But because of longer etching, lots of aluminium get dissolved in the bath and the section after anodizing looks worn out and has shades in it.
I am really tired of doing trial n error method. Will some one provide me technical assistance over it. How the bath should be prepared and what additives should I use?
Regards, Sumit

Sumit Lodha
aluminium anodizer - Ahmednagar, Maharashtra, India

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First of two simultaneous responses -- July 1, 2008

You could easily try different sizes of glass bead and at different pressures to find one that probably will do what you want.
Caustic it moderately cheap. Set up a tank off of the line for heavy etch. Add more caustic as required and then use the tank solution for waste treatment caustic source when it does not work well for you.

I think that what you are seeing is aluminum with large grain size and is oriented parallel to the surface. The grain size is affected by the heat treatment of the alloy as well as that specific alloy batch. Other alloys will not replicate it and some lots will not also.

James Watts
- Navarre, Florida

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Second of two simultaneous responses --

You will have to contact some consultant.

Ashok Jadja
- Anand
July 2, 2008

adv.