Help with gold electroforming

A. Raja, Here are two suppliers of the processes you require: Degussa (Germany) and Enthone-OMI. Good luck.

A. Hi, Mark. Sorry, I don't know the answer, but in addition to the companies mentioned, Technic has been offering gold electroforming processes around the globe for decades.

Regards,

A. Hi Jerry. If you want to learn on a budget, start with copper plating not gold plating. Mistakes are very costly when you're dealing with something that costs $1000 per ounce :-)

Please see our FAQ on plating/electroforming on organic objects.

Regards,

  Thank you Mr.Bob Lynch for your kind advice.

Mr. Jerry Landes: Please contact again for further discussion.

Thanks for FINISHING.COM for their generous help but do not want to say for the people who know but do not help.

God bless M/S Ted Mooney & Tom Pullizzi.

With salute and best regards

Ed. note: Thank you, Raja, and God bless you.

A. Dear Raja,
which carat are you interested in? If you want 24K, you don't need a special system but only a good electroforming process that can give you a hard deposit, with enough mechanical resistance.
For other carats (14, 18 and 21/22) you need a dedicated machine.
I think Enthone Inc. is a company that can provide you updated technology in this field.
Regards.
Alberto

A. Hi Heide l. Cardenio

Gold electroforming is a long process. Anyway, I will suggest to begin with 18 K gold electroforming where the technology knowledge is fairly established.
Process
Mould preparation using low melting alloys
Cyanide copper plating
Bright acid copper plating
ELECTROFORMING

A. Heide, The best electroforming I have seen is a process from Degussa in Germany. In this process the models are simply the waxes used for investment casting which are coated with a conductive coating then electroformed in the carat rating required. The process is however sold as a package (that is, you have to buy the machine with the computer controller as well as the plating processes).

Regards

A. Hello Heide. In the USA and much of the world, people do not attempt to formulate their own electroplating solutions; rather, they buy them from vendors like DeGussa, Technic, and others who have done decades of intensive development work; and Bob is doubtless right that you should stick with well developed 18K rather than trying 14K.

You can probably use stainless steel anodes in many cyanide gold plating baths. Although 24K anodes could probably be used, no one does that because of the cost and value of such anodes. 14K anodes would never work because gold is more noble than the copper, silver, or whatever other metal you would melt into it; studying the Nernst equation will reveal what the problem is.

It is obviously difficult to cover the whole technology of gold electroforming in a forum response, since it fills chapters if not whole books, but we'll start a topic here which will hopefully eventually cover a lot of it.

Regards,

? Hey Chris, Are you sure of the sulphate? I know that sodium gold sulfite is used in a non-cyanide gold plating system. Regards, Fred Mueller, CEF

A. Chris, Try Degussa in Germany or your local agent. They have a range of electroforming processes.

"Gold Plating Technology"
by Reid & Goldie
(hard to find & expensive; if you
see a copy cheap, act fast)


on eBay or

AbeBooks

or Amazon

(affil links)

A. Hi Utoomporn, Hi Zulema. It's a broad subject but Reid & Goldie's 630-page book on good plating has a 15-page chapter on the electroforming specific issues .

I do not believe that all the baths are cyanide gold but there are advantages in sticking with the proven standard.

Regards,

A. On the subject of gold electroforming solutions, there is also one made by Metalor, formerly Engelhard, called Enform 18P. You might like to contact the office in Cinderford Gloucestershire England.

Good luck!

A. Dear Charles!

Gold sulphite bath is not something for Do it Yourself work,but I think you can use ferrocyanide bath (0,5-1% of potassium cyanide toxicity). I am metalwork conservator and we used it for silver electroforming and it works.

potassium ferrocyanide ⇦this on eBay or Amazon [affil links] .....200 gm
Potassium carbonate.......40 gm
Gold chloride............. 50 gm
Water......................1 lit
stainless steel anode,or platinum plated titanium (never mix solution and acids)

A. Charles,

In the early 70's, I worked for Sel-Rex, the first maker of sulfite gold plating systems. One of the many things that I was in charge of was the manufacture of sodium gold sulfite. The process is dangerous - maybe even more so than the cyanide you're trying to avoid. There are bad acid fumes and, at one point, there is a great danger of producing the extremely explosive gold fulminate. Besides this, the process is tricky, exacting, expensive, and requires a good production chemistry background. The process was patented in the late 60's. The patent is about the only place that you'll find out where to make it. No one is going to tell you how.

Do the smart thing and buy the solution ready made. I would strongly suggest buying from Technic. They have always been innovative and helpful and they know as much about sulfite gold as anybody. Ask a lot of questions. Make sure the bath will plate to a thickness of 1.5 mm (.059"). Sulfite gold is not that easy to use. When things go wrong (and, they will), you'll many times need the free (usually), instant, expert advice that ONLY a supplier can give you - that's what you're paying for. Plus, you'll end up with a better, more reliable system. It's usually penny-wise and dollar-foolish to try and make your own chemicals or solutions, whether you're plating gold, nickel, silver, or whatever. Only amateurs do this, thinking that they'll save money.

A cyanide solution, containing about 4 tr.oz. of gold per gallon and using gold anodes, may still be the best (and, cheapest - and easiest) choice for electroforming gold. Technic, or other good gold bath suppliers, could sell you the PGC, give you a good bath formula, and tell you how to set it up and use it. Cyanide is safe if you know what you're doing and do it legally. It's not something you do in your garage. Check out thread #25979, read plating books, and search for other cyanide info on this forum and the internet. Be prepared.

Otherwise, find a plater. For small volume, this is your best choice. However, it makes experimentation more difficult.

---

"Electroplating and Electroforming for Artists and Craftsmen"
by Jay H. Newman

on AbeBooks

or eBay or

Amazon

(affil links)

2004

"Amateurs do this, thinking that they'll save money."

Good point, Chris. Professional platers rarely try to design their own process chemistry, whereas amateur platers often try.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hello Charles and plating colleagues, normally I would agree wholeheartedly with the advice given to "amateurs" embarking on this journey called electroplating. However, Charles is no amateur in the sense often used in this forum. Mr Lewiston-Brain is an accomplished technical researcher and practicing goldsmith. He is internationally recognized for his efforts in raising the safety awareness for practicing artists to the wide array of health hazards often encountered in the field of goldsmithing, sculpture and jewelry. He is highly regarded within his field and has provided accurate and easily understood information to anyone who would listen, especially educators. I have no doubt he will safely find a solution and methods to meet his requirements.

Charles, you are on the right track with regard to sulphite based gold chemistry for electroforming. Avoid the ferrocyanides; remediation is not good for this family of chemistries. As mentioned,there are commercial chemistries you can purchase that will meet your needs. Contrary to popular belief there are few people left within those companies mentioned that have the "actual" intimate and direct information (gold electroforming) based on empirical discovery which could help you. However,they can provide general principles and guidelines to follow if you can locate the right person. Other elements that will be critical to your success will include selecting the correct power supply, temperature and metal density of gold bath, agitation as well as numerous other variables which will need to be included. The cost for procuring the equipment, chemistries and the time to bring all the esoteric elements together is no small feat even for the accomplished plater. A very high degree of process control and bath monitoring is essential. You are probably familiar with the remarkable work of Stanley Lechtzin with regard to electroforming with copper. You will find that gold electroforming is significantly different (tougher) in chemistry, correct waveforms,and as you know costs.

By the way, try contacting Neil Bell from Red Sky Plating [a finishing.com supporting advertiser] as he also has expertise on this topic and has been consistently generous and gracious with his knowledge.

Best regards,

---

Thanks, David. I stand admonished for calling my betters "amateurs" :-)

It was a bad choice of words. I am in awe of how metal-working artists do what they do. What I probably should have said is that people who do industrial electroplating immediately learn that there is a whole industry out there that has worked for decades towards optimizing plating processes, whereas people who aren't into high volume plating may not realize that this is the customary approach, and might assume that they must make up plating solutions themselves from raw chemicals because that's what they remember from chemistry class.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Dear Charles!

I have used ferrocyanide bath over 10 years and I can tell you that it is very stable and easy to prepare.I have used it for gold plating, not for electroforming (2,65 gm gold chloride,15 gm potassium ferrocyanide ⇦this on eBay or Amazon [affil links] ,15 gm sodium carbonate ⇦this on eBay or Amazon] /for electroforming bath must be concentrated).

From financial point this type of bath is much cheaper than any proprietary product and, last but not least, several good books mentions it: Lowenheim's "Modern Electroplating", 1963 [on AbeBooks, eBay, or Amazon affil links] ; Dettner/Elzes Hanbuch der galvanotechnik/1963. If you don't want to work with it simple chloride based bath is also one possibility.

Chloride base bath:
gold chloride.......25-40 gm
HCl (1,19 gm/l)......20-50 gm
sodium chloride.....10-30 gm
H2SO4 (1,84 gm/l)....10-20 gm
water................1 lit
temp.................70 °C 8-10 A/dm2

Good luck!