Possible reasons for problem with silver plating on copper component

the first solution is depositing some Ag and picking up a little copper and later that copper get deposited. AgCN and Cu(CN)2 are not simple as we draw them here. they are cyanide complexes.

http://www.pfonline.com/articles/pfdmorrissey01.html

http://www.google.com/search?hl=en&q=%22cyanide+complex%22+%2B%22silver+plating%22&btnG=Google+Search

Use a solution made from Silver cyanide disolved in potassium cyanide this is made by adding potassium cyanide to silver nitrate solution until precipitation ceases and the disolving the precipitate in excess of potassium cyanide ands diluting until the solution contains about 2oz of silver per gallon. If the silver anode darkens there is not suffient free cyanide. In siver plating first dip in a weeak solution of nitrate of mercury.

All the best and wear gloves and don't forget to was well. PS. Cyanide is easily absorbed through the skin. Keep some ferrous sulfate solution close by in case of spills and splashes. Cyanide has a great affinity for iron. Good plating.

Make sure you use distilled water for these solutions.

It is fairly toxic.

Very toxic by inhalation, in contact with skin and if swallowed.
Potassium cyanide - LD50/oral/rat = 10 mg/kg
Hydrogen cyanide - LD50/oral/mouse = 3.7 mg/kg

So a 100 Kgm rat would be one hell of a rat that would take 1 gram to kill 50% of the subjects. mammals and man will all have similar sensitivity to cyanide.

http://www.emedicine.com/emerg/topic118.htm

Just to emphasize the point, hydrogen cyanide was used in the gas chambers in those states that used them.

Yes an evil way to go. Sodium cyanide into heated sulphuric acid.

Sorry for the howlers some how the mistakes always appear automatically even after spell checking! But the info is good.