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Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Bright Acid Copper Plating solution turned green
Q. Hello,
I have been using Bright Acid Copper Solution a long time; since last 3 months it was becoming more and more greenish almost like nickel solution. I was plating fine but on big parts (3 1/2 Sq Inch) I don't get bright and smooth finish.
Then I did carbon treatment over night and then I added Primary (Make Up) brightener about 3 ml/ltr, Sulfuric acid 10 ml/ltr and secondary brightener 0.3 ml/ltr.
After treatment solution was clear blue, problem is no shine and rough plating I need to use 800 grit sandpaper and polish manually, which takes time and won't get good finishing deep inside.
I use anode bags, Ti Baskets and phosphorized copper anodes with continuous filter.
I have to analyze to check all parameters. Before that if anybody has faced this kind of problem please advise.
Thank you
Dipen Pattni
jeweler/goldsmith - Dar-Es-Salaam, Tanzania
April 8, 2011
A. Hi, Dipen.
Bill Hemp advises us in letter 5001 that a dark green coloration is a result of organic contamination, which you have now removed. It sounds like your attempt at re-balancing the brighteners is not yet quite right. Do you have Hull Cell panels and, if so, is there any bright range?
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 11, 2011
A. You have very high chloride (HCl) in your bath. If put 1 g/l silver nitrate then put H2O2 about 2-3 g/l and heat the solution 50-60°; then do filtration.
Majed JaninehBeith Lehem Israel
October 2, 2011
A. No Majed, green colour is not due to the high chloride.
It's main cause is only organic contamination (as suggested by Ted sir)
I had the same problem, and after giving carbon treatment, solution is again blue and working well.
- delhi, India
June 7, 2016
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Q. Reference is made to a "Hull Cell". What is a "Hull Cell"? Bryan Moorhobby - Sale UK December 29, 2018 A. Hi Bryan. A "Hull Cell" is a specially designed trapezoidal miniature (267 ml) plating tank used to plate sample coupons. Its features allow us to learn a lot about the capability of the solution being tested, and its size is chosen to facilitate easily scaling up from test additions to proportionate corrective additions to the production plating tank. It's hard to full describe in a sentence or two, so please see thread 22320, "What is a Hull Cell Test, Why is it done, Where to Get a Hull Cell". Regards, Ted Mooney, P.E. RET Striving to live Aloha finishing.com - Pine Beach, New Jersey December 2018 |
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