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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing 1989-2024
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Protective masking for stripping and re-anodizing
Q. Good evening, I have a specific question.
I need to anodize some old aluminum pieces in which brass parts are inserted. These parts cannot be disassembled.
To prevent them from being damaged during the process they must be protected with something. I had thought about a special paint but the problem is two-fold.
Because the pieces of aluminum must be activated with sodium hydroxide before being inserted into the sulfuric acid. And we know well how aggressive sodium hydroxide is towards paints in general.
My question is, is there such a protective product on the market that can withstand both caustic soda and sulfuric acid? Or is there a less aggressive stripper/activator than caustic soda?
Or different suggestions.
Thank you.
Best regards,
- Italy
October 4, 2024
A. Hi Marcello. The answer is two-fold as well :-)
1. An alternate stripper is chromic-phosphoric acid, which dissolves the anodizing without attacking aluminum; you can search the site to learn a lot about that.
2. Commercial masking agents from suppliers such as Maskcoat LLC [a finishing.com supporting advertiser] are designed to withstand such chemicals.
The biggest issue however is that even if you think it will be hard to mask the brass, it will probably be harder than you think :-)
Luck & Regards,
Ted Mooney, P.E. RET
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