HOME FAQs BOOKS JOBS: Help Wanted Suggestions you are here: Hotline/Forum => Letter 39072

Brownish red gloppy stuff in copper plating experiment

++++++

My son's science project involves copper plating nickel keys in an electrolyte of vinegar and table salt. After about six hours of immersion, we have observed this reddish brownish lumpy residue being attracted to the keys. It does not adhere to the keys, and shakes off them in clumps. I'm guessing this is coming from the copper strips that we are using to plate with. This didn't happen the last time we tried to do this, and we are puzzled as to the cause. I have searched your sight for a solution, but haven't found one. I would appreciate any help.

Ann H.
Algonquin Middle School - Illinois, USA

++++++

One can only theorize in this case. My theory would be, that since vinegar is such a weak acid, that some copper dissolved and then the acidity of the solution decreased and the copper could no longer be held in solution and has precipitated out as a copper oxide sludge. Take a small amount of the sludgey solution and put it in some fresh vinegar and see if it dissolves.

Ted Mooney, P.E.
finishing.com
Brick, New Jersey

ANSWER or FOLLOW UP POST an unrelated QUESTION HOT Topics

Disclaimer: It is not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information
presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The
internet is largely anonymous; some names may be fictitious and some recommendations may be deliberately harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: