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Mystery Electrical Problem in Watts Nickel Bath

February 13, 2008

We barrel plate a lot of parts in a Watts type nickel bath. This problem started appearing about a month ago. The current level on my rectifier drops to less than 1/2 the normal level and fluctuates wildly. The parts stop plating and the danglers become dull and sometimes have nickel crystals on them. I think they are nickel sulphate crystals. I check all my electrical connections and they seem fine. For the heck of it I hooked up one lonely penny to the ground wire and plated it for a few seconds and then hooked up the barrel again and all was well. I have done this now three or four times and it seemed to solve the problem. Now it is not working anymore.

Right now I am dummy plating it to see if it works.

Is this polarized anodes? I ran 4 barrel loads through it today before this started happening again.

Terry Collins
Plating Shop - Cleveland, Ohio

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It is indeed a mystery, Terry. Personally, I don't think it involves passive anodes. That would prevent the anodes from dissolving properly but would not block current flow; plus the nickel concentration should drop, rather than grow, so crytallization would seem especially unlikely.

I don't like your use of the phrase 'ground wire'; neither pole of the system should be grounded.

My first guess is that it's simply your rectifier acting up. Try a substitute rectifier.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 13, 2008

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It sounds to me like you have a power problem, not an anode one. I would suggest you recheck all your electrical wiring and connections- even better, replace them all. Also check your rectifier is working as it is supposed to. I would also clean all the connections and bussbar contacts.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
February 17, 2008

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First of two simultaneous responses --

Dear Sir, the fist question is: when did you do the bath analysis recently. Please inform about the result. In my opinion you have very low chlorides ions in the bath. Very low boric acid is also possible.

Janusz LABEDZ
- Warsaw, Poland
February 19, 2008

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Second of two simultaneous responses --

Hi,
Check the recitifier because I think you have AC in the recitifier.

Regards
Anders Sundman

Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden
February 19, 2008

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Anders! Long time no hear. Welcome back.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 19, 2008

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Thanks for your replies. I have done an analysis on the bath and all the parameters are within normal.

I used the term ground wire in reference to the negative connection to the rectifier.

I agree that this must be an electrical problem. Since it only happens when I use the barrel I think I need to make certain I am not getting AC or a short through the barrel.

When I figure this out I will post the solution here.

Terry Collins
- Cleveland, Ohio
February 24, 2008

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In your first posting, you said you would do a dummy plating, how is it?
It seems to me that loose contact(it happen on certain barrel?) plus passivated anode caused your problem because with the same rectifier sometime it worked.

John Hu
- Singapore
February 26, 2008

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Hello,

If you have check all electricity and you rectifier please chek also the wetting agent in your nickel solution.

Regards

Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden
February 27, 2008

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Hi Terry,

Just a few questions. Is your rectifier constant current or constant voltage? You said the current is fluctuating.
How about the voltage, is it fluctuating as well? Do you have another rectifier so you that you can be sure whether it is your rectifier or not?

You also said the bath analysis was ok. What are you using to corrode the anode, Chloride or Bromide? How long have you been using the anode?

Good luck in your troubleshooting. It definitely looks like an electrcal problem.

Maurice.

Maurice Mason
Electroplating - Danbury, Connecticut, USA
February 29, 2008

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I agree with Anders as it is an AC impedence problem in the rectifier. I encountered an instance in which one of three fuses were blown in a standard tap switch rectifier. You may want to check.

Best of luck!

Ira Donovan, M.S.F.
Kansas City, Missouri
March 1, 2008

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Mr. Terry,

Please take hullcell and find out whether solution problem or current problem. Hull cell wil give clear indication.

Thanks,

P. Gurumoorthi
electroplating process chemicals - Chennai, Tamilnadu, India
March 5, 2008