Where the
world gathers for metal finishing
Q&As since 1989


-----

Rejuvenating cyanide based 24kt plating solutions

Greetings everyone. I'm trying to find any information on rejuvenating a cyanide based 24kt plating solution. Originally came in a 1 qt bottle with 1 DWT fine gold. I do some gold plating from time to time, custom small parts for electronics, etc, not too often though. I work with high pwr NdYag lasers for hobby, pulsed, flashed, and CW. One of my chambers need the inside reflector re-plated with 24kt gold, but my solutions are too weak to achieve a good thick fully polished and glossy re-plate. One reflector is in dire need of re-plate, and is relatively small being approx. 2" x 2"x 5" long. Originally they were entirely plated, only the inside elliptical curved area being highly polished like a mirror. Can anyone suggest, if it can be done that is, how to rejuvenate my cyanide based solution with a maximum amount of fine gold ? Thank you for some listening ears :) I am deaf, and have to use a special phone with headphones so it's too much of a struggle for me to hold a phone conversation, especially for the other party who will be repeating themselves many times.

I almost forgot to ask about the concentrated nitric acid used for making Aqua Regia. Can it be reagent grade, ~68-70%, or is 70%> , 95-98% funimg concentrate required? It seems to work fair using reagent grade but seems a little slow. I'm a little rusty with my college chemistry from the mid 80's, but I am aware that you don't mix any nitric with cyanide salts whatsoever. Thanks again for a little help and tutor from someone :)

Jeff Engle
Hobbyist, inventor, retired professional - Shingletown, California, USA
November 11, 2010