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Plating cyanide copper and then silver cyanide on to leaded steel

 

Plating cyanide copper and then silver cyanide on to leaded steel. Using fluoboric acid at about 80 to 90 percent with an electroclean process. Most parts ok but do get some blistering. Did use 100% h.c.l. but was getting a lot of blistering. Perhaps something better for prepping leaded steel. Also I heard that after a long time plating leaded steel in copper cyanide you can get lead build up in the copper tank which could cause blistering as well. If so how do you check for it and how do you fix it.

THANKS,

ELLIS DePRIMA

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I don't find Pb as causing blistering in a cyanide copper bath, The Garden State Electroplating School Course Manual, 9th Edition, 1986, Editor F.J. La Manna, states that lead will cause dull plate at 100 mg/liter. To remove, add zinc purifier (sulfide based) and filter. Add the purifier according the technical bulletin provided by the manufacturer.

Search the site for 12L14 to see other topics about leaded steel. Your fluoboric acid concentration seems a bit high.

  
Tom Pullizzi
Falls Township, Pennsylvania
 

Methane Sulfonic Acid also is a good activator for metal containing lead. Try using cathodic current in your acid activator for superior results.

Michael Brewington
- Salisbury, Maryland, USA