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Etching aluminum with caustic soda based etchant

I am looking for a chemical formulation for etching aluminium with NaOH, and for what must be added for smut etching. Any one out there who can help me?

Tika Sari
- Surabaya, East Java, Indonesia

Hello, Tika. I think your problem may be that you are trying to de-smut within the etch bath itself. The de-smut must be a separate acidic step designed to remove silicon, copper, or whatever alloying materials are in your aluminum; usually this requires an oxidizing acid like nitric or chromic acid for the copper, and a fluoride type acid if there is any silicon involved.

Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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