QuestionHi there, I hope you can help. I have made a ring in 9ct white gold (7% palladium)that needs to have an antique look - similar to what can be achieved by oxidising sterling silver.
My jewelry supply store here in South-Africa suggested a black plating liquid, but I was hoping you know of anything else that I could try which is not as expensive as the plating option. If you can suggest any products or chemicals that would be great. In a previous post I have noted someone was trying to get rid of black stains caused by chlorine- would this be an option? The ring has unreachable recessed areas and the idea is to make the diamonds stand out against a dark background. If black is not possible, I would also consider dark brown. Any help would be appreciated.
AnswerDear Anton,
A black plated layer would be the best if you could get it to plate well deep in the recesses. This is not easy to do if the settings and gemstones "shadow" the area behind. Think of the wave of ions bringing the plate to the gold as a beam of light and if the shadow would prevent the light from reaching. This same effect can prevent a uniform plated coloration in the shadowed area. And, yes indeed, the price is a vital consideration for the solution and for the rectifier, etc., to do a decent job of electroplate. So, the question is what else might work?
This would be quite easy if the general patina chemical for silver would work on gold. It will not. That is liver of sulfur (potash of sulfur) and as wonderful a patina as the chemical brings to silver, it simply is not workable with gold. In any regard, using this chemical is a wasted effort with gold alloys.
One chemical intended for gold is called Black Max. You may be able to find some information on this chemical on the net. To apply to gold, the item must be quite clean and free of any oils, etc. A bit of steel wool is used as an applicator and the black on gold derives from the reaction of the steel with the chemical. On silver, the chemical is used directly. Keep in mind, this Black Max will put dark color on gold but the color will NOT make it through an ultrasonic bath. The ultrasonic will remove the patina.
Beyond this, you may try iodine, daubed on. This chemical is in a family of chemicals known to lead to hidden corrosion in nickel white gold. Palladium alloys are much more resistant but prongs could be weakened. Use with care.
Otherwise, a black paint material will do the job. This will not maintain a color on a prong tip which is exposed to wear but will work very well in recesses. The trick is to get the paint to flow thinly into the recesses and not move up on the diamonds. A flat black is desired.
I do hope this helps. Obtaining a dark patina on gold is not easy in most cases and with diamonds set the task is more difficult.
Anton, best wishes with the project. Let me know if you remember how it turns out and what process was used. Fair enough?
God Bless and Peace, Thomas.
