Metal finishing Q&As since 1989

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How to check amount of metal in copper and silver plating baths?

I work for an electroplating company. We do silver and copper plating. In those plating baths we use copper, silver, potassium , and sodium cyanide to plate the parts. We are looking for a way to check the amount of silver and copper in the baths. Can anyone help me it would be very much appreciated.

Cynthianna Perry
Lab Tech - Jackson, MS, United States
July 2, 2008

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If your company can afford to operate a silver plate line, then I would think that they could afford a book or two to control it.
The Metal Finishing Guidebook is the simplest and is adequate. I would also buy, (Used?)one of the lab analysis books that are in the book section of this site.

James Watts
- Navarre, Florida
July 3, 2008

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First of two simultaneous responses --

Hi Cynthia,

I would suggest your company to use AAS (atomic absorption spectroscopy [on eBay or Amazon]) equipment because aside from it is easier to do and time-saving, I can guarantee you that results will be more accurate than any analysis method.

Diana Fe Espinosa
- Cebu City, Philippines
July 5, 2008

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Second of two simultaneous responses --

James is quite right. The analytic procedures are spelled out in the Metal Finishing Guidebook. I would also suggest that you or your employer begin a library of books about plating. Many good ones may not be the newest. Frequently used books may be available.

You should also use your suppliers as as resource. They will supply analytical instructions for the baths they supply. Also, these people can/may assist you in finding books and other information and might even instruct you in the analytic technique.

Gene Packman
process supplier - Great Neck, New York
July 5, 2008

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First of two simultaneous responses --

ICP would work very well.

Terry

Terry Tomt
- Auburn, Washington
July 9, 2008

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Second of two simultaneous responses --

I use titration to do copper analysis and metrohm company can help you to get and install that
it is not bad idea to contact them

Abraham Tshaye
- Minneapolis, MN, USA
July 10, 2008

For the determinations you can use AAS or ICP, but chances are you'd have to take large dilutions that would reduce the accuracy of your test. I'd recommend a titration for both of them. Check a plating manual for the methods, they're usually pretty easy and use inexpensive chemicals.

Jason Rothman
Chemist - Pomona, California
August 6, 2008

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August 7, 2008

I echo the people who recommended titration, not AAS or ICP, for these analyses.

Yes, it may be a great big expensive machine with a digital readout, but any competent chemist will get more accurate and precise results with a $50 buret.

Dave Wichern
Consultant - The Bronx, New York

I think that the instrument method is more accurate if the operator is properly trained, but I doubt if this shop can afford the instrument. The price of a good used instrument is too dear for a small shop. Besides, it amounts to measuring with a micrometer and cutting with a sledgehammer. It does not need that level of accuracy. A quarter of an inch difference in the liquid level will make more difference in the two answers, assuming that the sample is properly taken in both cases which it is not in many cases.

James Watts
- Navarre, Florida
August 8, 2008