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Concentration of etching soda for aluminum

please inform me about the best concentration of NaOH solution for etching aluminum on powder coating process. is it necessary to add sodium / potassium fluoride [affil links] (NaF / KF) to prevent coagulation of aluminum hydroxide? if necessary, what concentration salts suggested? is there any anti-coagulate or better? thank you so much for helping me.

Monta Hutajulu
plating shop employee - Batam, Indonesia
March 2, 2009

March 4, 2009

Hi, Monta. You can etch with 5 oz/gal free NaOH. Yes, NaF can be an additional ingredient. So can sodium gluconate. If you search this site for "aluminum caustic etch" you can pick up many pieces of the puzzle. You can also search expired patents. But proprietary etches are available from the chemical suppliers if you don't want to invest in the research to develop the ideal ratios of everything yourself. Good luck.

Regards,

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

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