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Copper electroforming problems


Current questions and answers:

April 19, 2022

Q. Hello! I've been making jewelry via Copper Electroforming for awhile. I stopped for a few months due to needing new solution. I made the new solution via copper sulfate, battery acid, and distilled water exactly like I've done in the past. However now, my rectifier times out or just isn't conducting anything? I just have a scrap piece of copper suspended in the liquid as a test but I can't get my rectifier to work. I've tried two rectifiers and two solutions. Tried plugging them into a different outlet as well.
Any tips to troubleshoot this?

S Kinsey
- Florence, SC

April 2022

A. Hi S. Make sure the input voltage switch on the back is correctly set, then test the rectifier's voltage controls and current controls per the instructions. If it performs correctly, maybe the rectifier is set for 0 Amps constant current; make sure it's set right. Oh, and make sure your hanging hook is copper; aluminum won't work.

If you are sure the rectifier is okay and you are operating it right, then: I am not confident that this is the problem you are having, and your solution doesn't look super saturated, but as food for thought, a copper plating solution which is too strong will not conduct. Some people call it the "anode going passive".

I am not a theoretical electrochemist able to fully explain it, but it seems that a very saturated solution causes a film to build around the anode which can't carry electricity.

After testing the rectifier, I'd suggest taking the anode out and scrubbing it with steel wool, and while it's out try diluting the solution 50:50 with DI water before putting the anode back in. Let us know if it changes anything.

Luck & Regards,

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

July 29, 2022

Q. Hello! I am having trouble with my 9 quart igloo homemade tank that I use for copper plating 3D models I make. My issue is I recently had to dump the old solution out due to it having sat inactive for about 6 months ... so I made a new solution using water, copper sulfate, a little battery acid, and a little table salt. The solution is plating the copper wires I'm hanging pieces from in the tank, but not the pieces themselves. I homemade my paint 10 or so months ago with graphite powder, modge podge, and water. I painted the pieces months ago as well. I am confused because the old solution worked fine for months and plated my stuff beautifully, but now I can't understand what I'm doing wrong now...

Thank you for your time!

Shy Perk
hobbyist - Indianapolis, Indiana

A. Hi. The way to start is probably to take a Hull Cell panel or other very platable substrate and try to plate that because it will tell you whether your plating setup is the problem or the substrate is the problem.

Luck & Regards,

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

Previous closely related Q&A's, oldest first:


Q. I am attempting to electrodeposit a copper layer on a silver coated conductive substrate (wax), resembling a large coin/medallion. It is very important to me to preserve as much of the surface detail as possible, because my next step will be to melt away the wax and use the plated copper as a mold. The diameter of the wax medallions is approximately 6 inches. I am experiencing surface burning, dendritic features, surface "wrinkles", porosity in the areas of low radius curvature, and spontaneous flowering of beads. I must be doing something wrong. Can anyone help me? Thanks for any info or advise.

D Marti

"Principles of Electroplating and Electroforming"
by Wm Blum
from Abe Books

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A. Hi, D. Yes, as you suspect, the problem is not the limitations of the technology, but that you are doing something wrong :-)

The preservation of detail that you are looking for is not even a challenge for a properly operating process. Compact discs with their billions of precise dimples, and record stampers, wave guides, precision screening and a host of super critical items are made by processes similar to yours.

First, please talk to a plating chemical supplier and consider getting a proprietary copper plating bath. Their leveling/brightening agents are the result of decades of research and development. Follow their technical data sheet, and you'll quickly see dramatic improvement. Then control the temperature as recommended, and keep the amperage in a very low range. You may also want to get out to some local AESF meetings to discuss your situation and polish your skills still further.

Although you want to minimize the defects you speak of, they are on the outside of the electroform and it is the inside surface that is most important because it will be replicated. Good luck.

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


A. My company also does electroforming on wax shapes (for a totally different application) and it sounds like a bath control problem. Follow the previous advice and tank to a qualified vendor. We are using a product that was developed for rotogravure (printing) but we control to a lower hardness. It is a proprietary bath and I'm sure other vendors have good products too.

bill vins
Bill Vins
microwave & cable assemblies - Mesa (what a place-a), Arizona

Leveler / Brightener for Acid Copper Electroforming




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

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A. Hi, Mark.

Sorry that commercial products are expensive to buy and ship, but virtually every production plating shop finds that they really are worth it. Hopefully a reader can offer some ideas for specific generic formulas, but I don't have any. In fact, I think that you might benefit from considering a different proprietary salt rather than copper sulphate.

One point to remember is it takes time to make a quality electroform--a lot of time! While it may be possible to acid copper plate at 40-50 ASF, you'll probably need to electroform at a small fraction of that to avoid nodules. Best of luck.

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


A. One thing is very important. Are you using air for agitation of the solution? If not, this is very important for distribution of copper and leveling. Then, and this is for the last 41 years, is a product that I use: its called UBAC#1. I also have made electroformed copper guitar, one piece guitar. I can also duplicate any wooden instrument in copper, but that's a different story.

David Neily
- Watsonville, California, USA

Electroforming rectifier questions


Q. I have recently purchased a small plating rectifier and accoutrements for my small jewelry business, and have attempted to electroform some small items as a sideline. Recently, the copper electroforming is, well, not working. I have had some success (a nice, bright finish), and some failures (a lumpy, dark finish -- because I "burnt" the process), but the last several attempts have resulted in a smooth, dark, oily finish -- what on earth have I done wrong? AND does it have anything to do with the fact that my rectifier is now "on the blink" and doesn't seem to transmit any electricity to the leads? (Although the oily finish started a day or so before the rectifier started acting up)

Blake Johnson
- Oakland, California


A. I have done an extensive amount of electroforming in my business. I have done everything from real flowers to baby shoes to wax models.

From some of your successful attempts, I assume that you are applying the conductive paint, silver nitrate, tin solution, etc., in a proper manner prior to plating. From my experience, you can look at the part after it had been in the tank for about a half an hour to get a very good indication whether your power (amps) is properly set. If the part is copper colored like a new penny, then your setting is perfect. Salmon-pink equals amps too low. Burnt brown or dark brown, amps too high. Try to calculate the area being electroformed as best you can. 10th of an amp per square inch … no less … no more. As for your rectifier, it may be on the blink.

Henry H Hemsley
Pewter and Plating - Bel Air, Maryland

thumbs up signVery exacting and informative, Henry. Thanks!


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

Copper electroforming with non hazardous chemicals


Q. I have absolutely no experience electroplating or electroforming with anything. My intention is to electroform copper onto a conductive paste. I want to avoid hazardous materials, even if it takes a great deal more time to build up the copper. I came across letter 4188, "9th grade electroplating science fair project" which suggests using acetic acid (vinegar), Epson salt (magnesium sulfate), sugar and dishwashing fluid (a drop).

I also came across a site that implied their particular electroforming solution was acid based (non alkaline? -- probably sulfuric acid?) but no details, and I also came across a detailed electroplating? formula:

0.25 M Copper Sulfate
1.8 M Sulfuric Acid
40-100 ppm Chloride ions
50-500 ppm Polyalkylene-Glycol
5-100 ppm Organic Sulfide (SPS)

Anyway, my questions are: Is it even feasible to electroform with an acetic acid in general? If so, does anyone have a good formula? Or could someone critique the formula that I pieced together:

5% acetic acid (vinegar)
0.25 M Copper Sulfate (62.48 grams/liter)
50-500 ppm Polyether (polyalkylene glycol)
some amount of Sugar?

I have so many questions (ugh). Is that formula realistic? Does anyone know how much sugar per liter is an optimal amount? Is Epson salt still needed or beneficial along with the copper sulfate? If so, does anyone know the optimal amount per liter? Does anyone know or is there a way I can estimate how high I can push and maintain the bulk copper concentrate, and an optimal realistic value to aim for (is more always better for the bulk copper concentrate)? With the absence of chloride, is polyether still an effective leveler? Does adding the drop of dishwashing fluid enhance that formula?

A couple of followup questions: the flow rate that I read so much about, does that refer more to the agitation of the solution, or the filtration pump recirculating rate, or both, or neither? When it comes to the agitation and number of times the solution gets filtered per hour, is more always better? One final question: in a setup like described does anyone know the highest voltage advisable without running the risk of "burning"; does that depend on the size of the bath and surface area of the copper anode? And can someone experienced point out to me where my novice / ignorance on electroplating is jumping out at them, and offer any information I'm lacking.

Best Regards,

Joseph James
- Bridgman, Michigan, USA


A. Hi Joseph, I can see that we have confused you a bit. Sorry, but please try to forget the idea of vinegar, epsom salt, and sugar! That was proposed solely to help grade school children present a science project with little risk (vinegar is exceptionally mild, and in every kitchen; epsom salt cannot release chlorine gas no matter what because it contains no chloride; sugar is a brightener of questionable if any value, but allows for safe experimenting whereas real brighteners can be hazardous). If a child knocks the project to the floor, which happens on science night in elementary school, there's no real problem. The solution is completely wrong for serious electroplating or electroforming for a dozen reasons.

As for hazardous materials, "'Toxic' is a matter of statute, not opinion" -- attributed from my recollection to former NJ Governor Tom Kean. When chemicals are employed on a commercial basis for electroplating they are, by law, categorically hazardous anyway. If you managed to electroform out of the school children's vinegar solution, you would still be, by law, generating regulated hazardous waste :-(

A realistic guideline about avoiding hazardous processes though would be to not consider using any cyanide-based solutions, any concentrated acid or alkali, any chromic acid, any cadmium, mercury or lead, or any fluoride compound no matter how dilute. Copper sulphate based solutions can be used for electroforming, and copper sulphate is often used in high schools for similar experiments.

As for the desired concentration of copper, it's pretty much "the more the better". A simplified explanation is that the copper ions must migrate across the solution and through the boundary layer, and you do not want the cathode ever "starved for copper" because then the excess electrons will pull hydrogen ions out of solution instead, leaving behind OH ions to neutralize the acid you need and causing other problems. High circulation rates make for better filtration and better ion transport across the solution.

As for what you might be missing that "jumps out at me", it's that real plating processes are not home-brew affairs. You don't mix them from basic chemicals; you buy a proprietary plating/electroforming solution from suppliers who have figured out, from years of research, exactly what they need to contain besides the bulk ingredients like copper sulphate. One other thing that jumps out is that you will find it productive of your time to visit a library and look for the "Metal Finishing Guidebook", the "Electroplating Engineering Handbook" [affil. link to book on Amazon], or another plating textbook; books are invariably arranged in a structured tutorial fashion where learning is straightforward, whereas wandering around between smatterings of web pages from different sites offers no organizational structure, so progress can be difficult and tedious, and always involves the ten steps forward / nine steps back protocol because you'll always partially misunderstand things when the information doesn't come to you in proper sequence :-)
Best of luck!

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

Eco friendly electroforming?


Q. Hi, this is Ornella from the RCA and I wanted to know if there is any kind of solution for electroforming in copper and silver that can be used and which would be not so bad for the environment? My work is based on this process but it is also related to Nature and I think it might be a bit paradoxical to use chemicals to say that we should take care about Nature … Let me know if you've got any suggestion. Thanks

student - UK


A. Hi Ornella. I don't necessarily see environmental harm from either of these processes. The potential environmental harm comes from misuse or mishandling of the process solutions, not from the electroformed object. But silver plating may only be practical from cyanide based solutions and they are quite dangerous to use, and only for the experienced, not for beginners. Copper should be fine, and if you need a contrasting color, maybe think of nickel rather than silver?

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


A. Acid copper electroforming is a comparatively harmless solution if compared with cyanide-based. As Silver electroforming solution you can use ferrocyanide bath (1% of cyanide toxicity and it works), phosphate bath (according to one ex-USSR handbook), or thiosulphate bath (according to one expired US patent) or you can buy proprietary bath. Hope it helps and good luck!

Goran Budija
- Zagreb, Croatia


A. Ted is right. All plating solutions are harmless to the environment until they are wrongly used and processed and let loose into the environment. However, if you want to take account of the carbon footprint of the solutions, then you need to do a complete life cycle analysis and I am not sure this has been done in the chemical industry. Electroforming is a precise and delicate science that has taken many years to perfect. It is not possible to formulate a new electrolyte that is green (although nickel solutions are all green!) as the requirements are for specific deposit properties. The best electroforming solution for nickel is nickel sulphamate and for silver it is silver cyanide. The trick to making these environmentally green is to keep them away from the environment and have sufficient environmental protection that they cannot get in contact with the environment.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

Several threads were merged; please forgive repetitiveness, chronology errors, or perceived disrespect towards earlier responses -- they probably weren't there then :-)

How to electroform copper anodes for spark erosion


Q. I want to make electroformed copper electrodes for spark erosion to make moulds for glass products with different designs. Can you suggest the method how it can be made, with the process and the know how? I am ready to enter into a technical tie-up or know-how transfer. Can you also suggest to me an alternate to make the designs in the moulds?

Parmanand P Acharya
mouldmaker - Baroda , Gujarat, India


A. In electroforming the basic principles involve the selection and special treatment of the mother surface to permit separation and a proper chemistry and plating parameters to produce very thick coatings without cracks, distortion or premature separation. From this very brief idea you can follow that you need a pattern with exactly the negative surface of the electrode (positive to the EDM mold surface). The rest is a matter of either years of personal research and involvement or the hiring of a professional in the field. One organization that could help you is The Nickel Development Institute.

Guillermo Marrufo
Monterrey, NL, Mexico

High-Strength Electroformed Copper Parts


Q. I'm interested in electroforming parts to create small, intricate pressure vessels. I've read all about large liquid rocket engines using electroformed nickel and copper structures to produces parts that would be near-impossible to machine. Obviously these rocket engine structures withstand an incredibly high amount of thermal and mechanical stresses.

My project involves electroforming copper parts that must be able to withstand a fairly high level of stress due to pressurization. Although I've done a bit of research I've never seen anyone directly compare the mechanical properties of electroformed parts to those of raw machined stock. Will I be able to electroform parts capable of taking appreciable loads?

From what I've read in texts and in some of the finishing.com posts, the best mechanical performance sounds like it comes from pure, clean copper sulfate solutions with relatively low current densities. Is that correct?

Can someone recommend a good starting point for me to experiment with the plating solution and current levels? My part has roughly 0.6 ft^2 of area and I'm hoping to deposit roughly 0.120 inch of thickness. There is no need to produce these parts quickly so it is acceptable if it takes a long time to plate on the desired thickness.

Thanks! Finishing.com is an amazing resource!


Ian Whittinghill
University of Southern California - Los Angeles, California, USA

Ed. note: Thank you for the kind words, Ian. As you've already discovered, we at finishing.com personally contribute little of the technical expertise; we rely on the generosity of a good number of regular contributors. When you thank us, we trust that they realize that you are thanking them.


A. I think you should get a copy of the book "Properties of Electrodeposited Metals and Alloys" [affil. link to book on Amazon], by W. Safranek. It's full of references to the properties of electroplated or electroformed copper (and other metals too) using different electrolytes and conditions. Also, mechanical work hardens copper (all kinds) and makes it more resistant.

Guillermo Marrufo
Monterrey, NL, Mexico


A. Also get ASTM B832 [affil. link to spec at Techstreet], 'Standard Guide for Electroforming with Nickel and Copper',
and a freebie, 'INCO NICKEL ELECTROFORMING PROCESSES AND APPLICATIONS' at www.inco.com/customercentre/nickelplating/science/pdf/EcopyElectroformingGuide.pdf

The above items together are basically an update of the Electroforming chapter in Electroplating Engineering Handbook, 4th Edn., although omit iron electroforming.

The Electroforming chapter in The Canning Handbook, pages 573-590 (23rd Edn.), gives more information on plating Ni-Co alloys.

The Electroforming chapter in ASM Handbook, Vol. 5 Surface Engineering, is short but gives more iron plating solutions and mentions periodic current reversal for producing fine-grained copper of excellent mechanical properties in greater thicknesses.

One probably can locate additional information by searching on the authors and titles of papers presented at the 1996 AESF & NiDI Electroforming Course & Symposium, www.finishing.com/library/conferences/eform96.html

However, I have some doubt that an electroformed copper pressure vessel is permissible under the ASME Boiler and Pressure Vessel Code. Staying below 10 inches diameter will avoid the regulations.

Also, pure copper isn't very strong and suffers from creep when moderately heated, so normally isn't used for pressure vessels. The wrought Cu alloys typically used are alloyed with Ni, Sn, Al, Fe, Zn, Mn, etc.* and have annealed strengths 1.5 to 4 times that of pure Cu. For higher strengths, Cu can be clad onto steel.** The NASA rocket application requires extremely high thermal conductivity rather than high strength -- an oxygen-hydrogen combustion chamber is cooled by liquid hydrogen -- so the only alternatives to copper are silver & gold.

* ASTM B171/B171M [affil. link to spec at Techstreet] , 'Standard Specification for Copper-Alloy Plate and Sheet for Pressure Vessels, Condensers, and Heat Exchangers,' and ASTM B96/96M [affil. link to spec at Techstreet] , 'Standard Specification for Copper-Silicon Alloy Plate, Sheet, Strip, and Rolled Bar for General Purposes and Pressure Vessels.'

** ASTM B432 [affil. link to spec at Techstreet], 'Standard Specification for Copper and Copper Alloy Clad Steel Plate.' "The material is generally intended for pressure vessel use but may be used in other structural applications where corrosion resistance or conductivity of the alloy is of prime importance."

Ken Vlach [dec]
- Goleta, California

contributor of the year Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.

Ed. note, Dec 2016: As an update to Ken's incredibly generous bibliography & research, Inco is now a part of Vale which sadly seems uninterested in the product stewardship that Inco was so noted for. Sorry, not only can't we find that one particular article but, unless I'm missing something, I see none of Inco's famous white papers on their site anymore :-(
However, Gar Electroforming is currently maintaining a copy of that paper at
Download it while you can, product stewardship seems so 'yesterday' for today's megacorps :-)

Treeing / burning only on bottom of electroformed objects


Q. Treeing and burning only on bottom side of acid copper electroformed objects? I am using a simple acid copper bath for electroforming on ceramics. It seems that no matter where I place the anodes, or how I agitate the solution, dendrites form much more on the lower portion of the object. They also show blackening unless I scale the current way back. I don't get it … the solution concentration should be the same through any vertical cross section of the bath, and even if I place the anodes higher than the center point of the object or move them away, the bottom still forms a denser dendritic growth (with blackening) than the top or sides. What am I not taking into account?

Robert Coyle
product designer - Santa Fe, New Mexico, USA


A. Hi Robert,
If this was high current density burning you would think you would be getting it at the top or at the point of rack/wire to part or outer edges. Because I don't know of your exact bath make-up, I can only suggest fixturing a copper thieving strip an inch or so below the part. If you can't incorporate the thief strip on the rack or wire you can hang the strip from the cathode bar with two pieces of copper wire for placement. This will help, and most likely eliminate burning. Good Luck!

Mark Baker
Process Engineer - Syracuse, New York


A. Either the bottom of your anodes hangs well below the part, or you are getting stray current through something metallic which is below the part. Piping, heater, etc.

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg, South Carolina


Q. I have tried raising the anodes so they are well above the midpoint of the object being plated. The geometry of the object doesn't seem to matter. I still plates selectively on the bottom side.

I am plating glazed ceramics that are somewhat acid sensitive so I am using a copper sulphate/acetic acid/boric acid solution that seems to plate well but doesn't attack the glaze as sulfuric or HCl would.

I did find a little anode metal precipitated out at the bottom of the tank. Maybe that's the problem? I'll clean it out and try again.


Bob Coyle

Robert P Coyle [returning]
- Santa Fe, New Mexico, USA


A. I think that Mark is on the right track. Current will bounce off the floor of the tank and increase plate on the bottom. I also wonder if you have enough agitation in the tank.

James Watts
- Navarre, Florida

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