Removing gold plating from silverware

[ItayEdry]

So I am a jeweler based in New Orleans, LA USA. I recently was given a task of removing a gold plating from an antique silverware set. The one piece that I have experimented with was very easy to remove the gold from by using a buffing wheel so I accepted the challenge of removing the gold plating from whole set of 150+ pieces. Soon enough I have learned that the majority of those items are plated with a very heavy layer of gold that will be impossible to remove buffing without damaging the delicate patterns of the silverware. I was referred to this forum by a friend.
Here is the technical part:
*I am seeking advice on how to chemically remove the gold plating.
*The under-metal is solid sterling silver
*I am not necessarily interested in recovering the gold (though it would be nice to do so if I do not need to greatly invest in equipment)
*Some of the pieces (the knives) have a stainless steel part
*The silver must not be damaged

Any advice would be greatly appreciated

 

[FrugalRefiner]

*I am seeking advice on how to chemically remove the gold plating.
*The under-metal is solid sterling silver
*I am not necessarily interested in recovering the gold (though it would be nice to do so if I do not need to greatly invest in equipment)
*Some of the pieces (the knives) have a stainless steel part
*The silver must not be damaged

That's going to be a tough task considering you don't want to damage the silver. As you're aware, buffing will damage it, at least to some degree.

There are a couple of methods used to strip gold plating.

Many members use a sulfuric acid stripping cell to remove gold plating. But they use it on gold plated base metals. The base metals don't react to the cell like the gold plating, but the silver probably will, so its finish may be damaged.

Some advanced members who refine for a living use cyanide to strip gold plating, but in inexperienced hands, cyanide can be deadly. Like the sulfuric stripping cell, cyanide can also dissolve silver, so again the silver may be damaged.

Unfortunately, I don't have a solution for you, but I thought I'd mention the two most common ways of removing gold plating and point out the problems with the material you have. Someone with experience may be able to process your items without significant damage. Maybe someone else will have a better answer.

Dave

 

[jimdoc]

Maybe replate it silver over the gold?

 

[goldsilverpro]

So I am a jeweler based in New Orleans, LA USA. I recently was given a task of removing a gold plating from an antique silverware set. The one piece that I have experimented with was very easy to remove the gold from by using a buffing wheel so I accepted the challenge of removing the gold plating from whole set of 150+ pieces. Soon enough I have learned that the majority of those items are plated with a very heavy layer of gold that will be impossible to remove buffing without damaging the delicate patterns of the silverware. I was referred to this forum by a friend.
Here is the technical part:
*I am seeking advice on how to chemically remove the gold plating.
*The under-metal is solid sterling silver
*I am not necessarily interested in recovering the gold (though it would be nice to do so if I do not need to greatly invest in equipment)
*Some of the pieces (the knives) have a stainless steel part
*The silver must not be damaged

Any advice would be greatly appreciated

You can't use the Sulfuric stripper, cyanide, or Iodine/iodide.They all attack silver

On the pieces that are only sterling, you might be able to use a fairly dilute, room temperature, aqua regia, to remove the gold. Hydrochloric (or, Muriatic acid) acid combined with some bleach or hydrogen peroxide might work well.. A thin, milky silver chloride layer would probably form of the surface, but buffing should easily remove it. I would have some sterling pieces gold plated and experiment first. Of course, you couldn't put the stainless knife blades in any of those solutions.

Glass bead peening might work. Even small steel shot peening is possible. About 40 years ago, I tried both types on several different plated items,with several different types of plating, and they worked well, with no visible distortion of the pieces. The peening seemed to stretch the plating laterally and it just lost it's bond and fell off. Peening could produce work hardening of the surface, but I can't see that being a problem. Peening is not an abrasive process and would not remove any of the silver.

Good Luck!

 

[ItayEdry]

Thank you guys for the great ideas, that gave me some new directions to research. Through my research I found a company out of NY that sales a gold stripping solution that is cyanide based and supposedly would not damage the silver. Did anyone here every heard about it? will it work? I would love to hear any ideas and suggestions.

 

[nickvc]

If you use a very weak cyanide solution it becomes a lot more selective about what it will dissolve, I’m not sure that would apply to gold plated silver as cyanide will happily dissolve both but it might be worth a trial.

 

[nickvc]

Another thought if you plate gold directly onto silver it will eventually migrate into the silver so it’s possible you have a barrier plate underneath, if you have access to an xrf it might well tell you whether you have a nickel plate over the silver and then gold, if so cyanide will do a perfect job if done carefully and not too strong.

 

[ItayEdry]

Thank you guys for helping me out on that project. After some more research I decided to remove the gold plating off the silverware with a potassium cyanide based gold stripping solution sold by a plating supplier based in NYC. The solution was very expensive it coast $80 / liter and it took me 3 liter so far to get to 75% of the project done. The label on the solution claims that a liter can hold 60g of gold and after reading about how potassium cyanide works I am sure that the main volume of the metal that is dissolved in the solution is silver (the base metal for the silverware is sterling silver). For the sake of science I am going to try and refine the metal out of the solution my self. I found this a discussion about the topic in the following link. If anyone has any additional advice to add I am open to ideas. https://www.finishing.com/535/11.shtml