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Acid cadmium vs. Cyanide cadmium bath

DEAR SIR,

CAN YOU GIVE COMPARISON OF CADMIUM CN BATH WITH ACID CADMIUM BATH.
PRESENTLY WE ARE USING CN BATH WITH SMOOTH PRODUCTION. BUT DUE TO SOME LOCAL REGULATION WE ARE FORCED TO ELIMINATE CN TOTALLY.

THANKS,

K.M.BHATT.

KAMLESH M. BHATT
PLATING MANAGER - PUNE, MAHARASTRA, INDIA
February 4, 2010

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Hi, Kamlesh. Acid doesn't offer the cleaning power of cyanide. And because the metal is dissolved as a simple salt, rather than complexed, it won't offer the covering power and throwing power. But the biggest thing to watch for is safety issues. My personal opinion is that cadmium oxide powder can be more dangerous than cyanide.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 5, 2010

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February 8, 2010

I have run both types in the distant past. We only ran completely machined small parts that were very well cleaned and etched in the acid tank. I actually liked it. It was a proprietary mix that 3M developed over 30 years ago. They sold the formula to another chemical company that quit making it as they could not sell enough when the big push started on eliminating the use of Cd. The additives are what gave a good product. Most home brews will have problems.
That said, I think that it was patented and the patent should have expired, so you may be able to find the general formulation there. One component was a type of pyridine as it smelled like rotten fish.
I rather doubt if any decent sized reputable company sells acid cad anymore.
IF they do, try it in the lab and then a pilot line before you jump into it.

James Watts
- Navarre, Florida