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Jeweler sees bad color/streaks through nickel-gold plating at soldered areas

My name is Bob Ross and I have a small jewelry and insignia manufacturing shop. I recently started plating some small items in a small tank and beakers [beakers on eBay or Amazon [affil links] . However, when I plate an item gold (after a nickel base plate) I get bad results with items that have soft soldered attachments. The solder either does not plate gold or the piece will have a black streak emanating from the soldered attachment. Is there a cleaner or different preplate to cover the soldered item or prevent the black streaking?

Bob Ross
- Montvale, New Jesey, USA
2007

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2007

One of the evils of doing your own plating it the learning curve. You say soft solder. If that contains lead, it will be very difficult to activate without using a fluoboric acid etch.
If it is another solder, your cleaning and activation procedures are not working on the solder, which is very common. Your line needs to be tweaked.
There is a high probability that your nickel layer is not thick enough to be a complete barrier to prevent some metals from bleeding thru the nickel and then staining the gold.

James Watts
- Navarre, Florida

I checked the contents of our solder paste and it contains tin and silver (no lead) and has flux added. I agree that the nickel plate is not covering the solder. We tried to plate the items with copper first to cover the solder. Although we have had some success with the copper it does not cover consistently. Can you suggest a cleaning solution or a certain type of activation solution to use?

Bob Ross
- Montvale, New York
2007

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