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Aluminium Turns black in EN

July 16, 2008

I could do with a little help here. I am trying to EN plate some aluminium but when the part comes out it is black and in parts flakey. Also some parts are not plating at all.
I have double checked my process and everything is correct.
The EN took extremely well in a small area that was gold plated.
I polish the part then use a SP degreaser
Then Zincate the part until a gray even coating has covered the part
Then a good rinse and into EN
Does anyone know what is happening and how I would correct this I have done this successfully a few times using the same method.

David Scott
Plating shop employee, hobbyist - Glasgow Scotland

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This subject has been posted many times. It is very difficult to succeed using conventional zincate formulas. Try using proprietary chemicals. Vendors will come to your place and wittness what you are doing to help you out. G. Marrufo-Mexico Guillermo Marrufo - Monterrey, Mexico July 18, 2008 My nickel's opinion is that you are over-zincating the part. I would do a zincate-strip and lightly zincate--The double zincate process. James Watts - Navarre, Florida July 17, 2008

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July 30, 2008

Thanks for the response.
J, Watt you were absolutely right.
I got a amazing nickel plate just can't get it to activate now haven't a clue why?//

David Scott
- Scotland

Ok David, give us a clue. Why do you want to reactivate the EN?

James Watts
- Navarre, Florida
July 31, 2008

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August 3, 2008

I want to gold plate it. When I tried to go to gold a cream came off the part and of course the gold did not adhere. I recon its the polish I've used. very expensive stuff I recon when it says protects it really means make more difficult. Other thing I tried was MEK / methyl ethyl ketone to degrease the part, I have been told MEK won't work I should try acetone ⇦ this on eBay or Amazon [affil links] Warning! highly Flammable! but I was under the impression MEK was stronger than acetone.

David Scott
- Scotland

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August 5, 2008

Actually, different organics require different solvents for the best removal. There is no best one until you know what you are trying to remove. Trial and error will probably work best.

I think that you will find that the heat generated from the polish stem may have formed an organo-metallic compound which may be impossible to remove without damaging your EN.

EN is nearly as smooth as the parent metal is, so you should be able to avoid polishing the nickel. Check your other post for a possible activation material.

James Watts
- Navarre, Florida