Metal finishing Q&As since 1989

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The "Not Anodizing" Process

I just want to know the name of the process that is not anodizing. Aluminum is dipped in heated acid for 5 minutes or more at temperature from 70 °C up. Also I would like the name of solution as well.

Kindly reply me at your convenience.

Charlie Kiattaweesup
Kijsiam - Banpong, Ratchaburi, Thailand
2003

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Hi Charlie. Sorry, but I have no idea what process you are talking about, but if you could tell us the properties that this process is supposed to impart maybe we will understand you better. Thanks.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

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You may be thinking of a chemical polishing solution known as bright dip. It is a nasty combination of acids that requires a lot of heat, fume scrubbing, and an on-site chemist to maintain the solution parameters within narrow limits. Plus, it only works well on certain of the purer alloys, not the high-strength ones. Because of these and a few more reasons, the majority of anodizing companies do not use this process.

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
2003

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There is also a treatment done to aluminum known as Chromate conversion coating. It works without electric current and provides several grades of corrosion resistance depending on many factors such as alloy, bath chemistry, parameters, etc. The basic principle accounts for the development of chromium compounds on the alum surface. Look for Chromate conversion in your favorite search engine (Alodine, Iridite and alocrom are just a few commercial names of these type of processes).

Guillermo Marrufo
Monterrey, NL, Mexico
2003