# gold plating solutins



## arthur kierski (May 10, 2011)

i make rh sulfate solutions for plating----my solution is very pure and the results are very good--they are solutions containing 2grams of rh per 100ml of solution.(diluted to 1liter with distiled water)
now my customers are asking for gold plating solutions containing 1gram of gold per liter----
this gold plating solution sold by others,is made with cianides(nacn or kcn or both together)----

the gold i obtain from e-scrap-----the rh i obtain from cats----
Could some members give me some formulations or ideas of how should i proceed to go ahead with my project ?
by the way, i make 30rh solutions monthly =60grams of rh and sell the rh for220dollars a gram

the gold could be sold for at least 110 dollars a gram---the demand for gold plating solutions here,are much higher then rh plating solutions--
thanks for any sugestions and or formulations or ideas
Regards to all, 
Arthur


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## dtectr (May 10, 2011)

are you wanting cyanide solutions or non-cyanide solutions? i think i have msds and/or formulation for both somewhere.
let me know.
dtectr


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## goldsilverpro (May 10, 2011)

arthur kierski said:


> i make rh sulfate solutions for plating----my solution is very pure and the results are very good--they are solutions containing 2grams of rh per 100ml of solution.(diluted to 1liter with distiled water)
> now my customers are asking for gold plating solutions containing 1gram of gold per liter----
> this gold plating solution sold by others,is made with cianides(nacn or kcn or both together)----
> 
> ...



Arthur, you're getting too rich.

I assume it would be used for plating costume jewelry. It not, please tell me what it will be used for. A 1 g/l gold plating soln is too weak for most any electronics applications I can think of.

Making decent gold plating solutions from scratch is not a simple thing to do. Most start with PGC [potassium gold cyanide = KAu(CN)2]. PGC is manufactured separately and the manufacturing process is difficult and also dangerous, due to the very possible evolution of HCN gas. 

On the internet, you will find formulas for simpler solutions made with other chemicals, such as gold chloride in a ferrocyanide matrix, but these are far inferior to those made with PGC. I would stay away from these.

A company I once worked for manufactured and sold at least 100 (maybe, 200) different gold plating formulations for different applications. Except for 3 or 4, all of these started with PGC. The exceptions used sodium gold sulfite, which is even harder to make than PGC.

Were I you, I would first try to find a source for purchasing PURE ready-made PGC in crystal form. This could save you a lot of grief. When pure, PGC contains 68.36% gold. If you buy enough, you might be able to come close to doubling your money. From this, I'm sure we can find a bath formulation that will work well for the particular way in which the bath will be used.

Chris


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## nickvc (May 10, 2011)

Many years back we looked at producing PGC but as GSP pointed out it's not the easiest thing to make, it's a shame we live so far apart as I get PGC on a fairly regular basis.
Your best option may be to try and do a deal with one of the big boys, Metalor,JM or Englehard and see if they will play ball if you supply gold upfront otherwise it's not cheap to buy unless your a major user.


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## arthur kierski (May 10, 2011)

Nickvc and Chris-----thanks for the replies-------yes ,the plating solution is for costume jewllery---
i will go after pgc with some local dealer---if i obtain the product ,i will make contact with you.Nickvc idea of giving gold upfront is very good (since my gold comes from e-scrap)
Chris i am not getting rich (iwould like to), because my sales of rh plating solutions since the 2008 crisis became zero----only now in 2011 that my sales became stable again---- 
Thanks again and regards to both of you
Arthur kierski


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## Harold_V (May 11, 2011)

Needless to say, I bow to Chris' expertise where plating solutions are concerned, but let me share a little thing with you that I experienced. 
An old friend, now deceased, asked me to gold plate a railroad spike for him. I thought it was a great idea! He provided a couple new spikes, which I bead blasted to remove scale, then I had one of my customers give them a coating of nickel, to prevent migration of the gold in to the steel. I then plated with home made gold plating solution which I made by dissolving gold in AR. It was evaporated to a very thick syrup, then dissolved in cyanide. The deep red color is lost immediately, and you are left with an ever so slightly colored solution of gold cyanide. If one was to suggest a color, it would be a VERY pale yellow. 

I still have the solution and the pure rolled gold I used as the anode. Here's a picture of the spike I kept for myself. 

Harold


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## qst42know (May 11, 2011)

> made by dissolving gold in AR. It was evaporated to a very thick syrup, then dissolved in cyanide.



That sounds like a quick means to an end. At least without an excellent hood.


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## Claudie (May 11, 2011)

Harold_V said:


> Needless to say, I bow to Chris' expertise where plating solutions are concerned, but let me share a little thing with you that I experienced.
> An old friend, now deceased, asked me to gold plate a railroad spike for him. I thought it was a great idea! He provided a couple new spikes, which I bead blasted to remove scale, then I had one of my customers give them a coating of nickel, to prevent migration of the gold in to the steel. I then plated with home made gold plating solution which I made by dissolving gold in AR. It was evaporated to a very thick syrup, then dissolved in cyanide. The deep red color is lost immediately, and you are left with an ever so slightly colored solution of gold cyanide. If one was to suggest a color, it would be a VERY pale yellow.
> 
> I still have the solution and the pure rolled gold I used as the anode. Here's a picture of the spike I kept for myself.
> ...




Beautiful spike Harold.


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## Harold_V (May 11, 2011)

qst42know said:


> > made by dissolving gold in AR. It was evaporated to a very thick syrup, then dissolved in cyanide.
> 
> 
> 
> That sounds like a quick means to an end. At least without an excellent hood.


I did this about twenty years ago, and, yes, I had a good hood, but I'm not convinced it was necessary. If you evaporate the solution well, there is precious little acid present, so there's little, if any, hydrocyanic acid developed. I don't recall anything out of the ordinary when I dissolved the gold chloride---it was seamless. 

When I operated my agitation tank, using bromine and cyanide, free cyanide and pH were critical. I often had to add sulfuric acid to the solution to keep within the required parameters. Again, no big deal. 

Harold


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## Harold_V (May 11, 2011)

Claudie said:


> Beautiful spike Harold.


Thanks. I was well pleased with the results, but I have no experience with gold plating aside from this one venture. My point was, and is, that one _can_ produce a plating solution that will serve. How well is the question. 

Harold


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## goldsilverpro (May 12, 2011)

Harold and Arthur,

Essentially, Harold, you produced a solution of potassium or sodium gold cyanide with some extra K or Na cyanide and this combo is able to deposit fairly bright gold 24K plating. The thickness you are able to plate is mainly dependent on the amount of gold in solution. Arthur wants to make a 1 g/l solution, which will be limited to about 4-5 millionths of an inch, more or less. If Harold's solution contained more gold, it was not nearly as limited to these thickness and time-in-tank restraints as those using a 1 g/l solution will be.

Here's a typical makeup formula for 24K flash gold from an old Metal Finishing Guidebook (1968). Officially, flash gold is defined as anything less than 7 millionths. In the industry, flash gold is sometimes called "color" gold - just enough gold thickness to provide the right color. The brightness will depend on the brightness of the underlying nickel. If the part is left in the tank too long, the gold deposit will start getting dull.

PGC - .2 - .5 oz/gal (about 1.0 - 2.5 g/l of Au)
KCN - 2 oz/gal (15 g/l)
Temp - 140-160F
Current density - 20-30 amps/ft2
Anodes - 316 stainless
Time - about 10-15 seconds with agitation of the parts being plated

Most all of the available color golds use stainless anodes and that is what the jewelers are used to. The way Harold produced the PGC (or SGC), there would be chloride contamination in the solution. This could attack the stainless and contaminate the solution. After it is used a few times this metal contamination would most likely change the color of the deposit and perhaps create other problems and the jewelers would not like this. Gold anodes might solve this problem, but I doubt if the jewelers would like that either. The much more complicated methods used commercially to produce PGC end up with a pure and much more consistent product which, in my mind, is a necessity.

Color golds are produced in a myriad of karats and colors and I would guess that 24K is the least used color among jewelers. To produce the lesser karats in various colors, alloying salts, such as potassium copper cyanide or potassium silver cyanide, would have to be added to the solution. These salts are just as difficult to manufacture as PGC, or more so. Also, every jeweler I've ever known is very picky about the colors he wants to produce. In the book that I got the above formula from, I noticed this full page ad directed towards jewelers from Sel-Rex, the company I worked for at the time this book was written. To me, this ad says it all about the mindsets of jewelers.

"MATCH IT! Pick the gold color you want, and we'll match it...every time. With a plating bath that will continue to produce your exact color."

Making a plating solution for your own use is one thing but making a solution to sell is a totally different deal. Besides the right color, the main thing required is a consistent product. To me, the only way to get a high quality consistent product is to start with an excellent bath formula and then use exacting amounts of pure chemicals and pure water to make it up.

Chris


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## Harold_V (May 13, 2011)

goldsilverpro said:


> Harold and Arthur,
> 
> Essentially, Harold, you produced a solution of potassium or sodium gold cyanide with some extra K or Na cyanide and this combo is able to deposit fairly bright gold 24K plating. The thickness you are able to plate is mainly dependent on the amount of gold in solution.


While I don't recall the exact process, I, too, was limited as to depth of deposit. If memory serves, the spikes were removed and hand buffed a couple times, because the plating thickness was quick to go dull. 

I hadn't considered the problems of residual chorides in regards to using stainless. My choice of using a gold anode proved to be the right decision. 

Thanks for the comments, Chris. Aside from doing one more project (in copper), I have no plating experience. 

Harold


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## zachy (Dec 10, 2019)

I am manufacturing GPC, through the technique of porous glass, it seems to me that it is easier to obtain than by chemical means using royal water, as you know the formation of trivalent gold is not as effective when you are going to deposit it in jeweler baths and ornaments .

The CPG, which is obtained by the technique of the porous vessel is better. It offers better results. This solution is sometimes brown, but the ideal is that it is light yellow.


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