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topic 0085p4

Copper electroforming problems

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A discussion started in 1995 but continuing through 2018

January 7, 2017

Q. Hello, I have a few questions.
1) How do you correct your copper solution if you have an organic contamination?
2) Also, how do you know when the pH level needs to be changed and how do you do so?
3) I use graphite paint and Midas copper electroforming solution. I've used this on silver, brass, copper etc.
I've seen silver conductive paint and solutions and it's way more expensive. At what point do you use those? Am I not supposed to use the graphite paint and solution on metals other than copper?
Thank you!

Zoey Kemp
- Kona, Hawaii, USA

affil. link
Copper Plating Solution

affil. link
Copper Plating Solution

March 12, 2017

Q. Hi there,

I just started electroforming jewelry and had some success in some success. However, recently my pieces have been coming out not copper toned but salmony. I've already replenished with distilled water, and added more brightener. I also tried Dremel polishing and steel brushing the piece to try to bring out the copper colour but it just made it a shinier salmon colour … can anyone tell me why I can no longer achieve the rich gold tone?

Thank you!

Justina Lee
- Vancouver, BC, Canada

June 17, 2017 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I have a piece I am electroforming. I need to leave and wondering if I can turn off rectifier and come back to it later? If so, can I leave it in the solution, or should I take out, rinse and let sit?

Thank you,

Rebecca Hawks
hobby, jewelry designer - Oceanside, California

June 2017

A. Hi Rebecca. We appended your inquiry to a thread about electroforming of copper. Please confirm that you are doing copper electroforming from copper sulphate because, while that would probably be okay to interrupt, other processes like nickel electroforming would be ruined by such interruptions.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

June 21, 2017

thumbs up sign Yes, I am electroforming with copper electroforming solution

Thank you!

Rebecca kenney [returning]
- Oceanside, California USA

Copper electroforming pinholes, grooves and flaws

October 15, 2017

Q. I am dong some copper electroforming on a small scale at home for a model engineering project. It is going quite well but I have trouble with the apparently random formation of odd little grooves, a few thou deep, sometimes connected to a pinhole. They are up to an inch long(usually shorter) and tend to run vertically. I can sand them out but this adds to the work.
I am using a standard acid electrolyte with levelers, chloride, etc., all to a known recipe. Current density is about 50 mA per sq inch. Total required thickness is approx. 0.5 mm and area of the cathode is 42 sq inch. I use anode bags but have not been using phosphorised copper, to save money. I have no way of analysing the bath.
The base material is a low melt tin/bismuth alloy which is melted out afterwards.The cathode shape is simple and smooth with no holes. The final copper sheath is strong enough and appears OK but needs a bit of sanding work to get it smooth. I can fill the worst flaws with solder and plate over but this is a nuisance.
Any ideas? Also can someone please tell me where the agitation bubbles should be placed relative to the cathode?

Many thanks

Stephen Wessel
model engineer/hobbyist - Shepton Mallet, UK

What copper plating solution for electroforming 150 µ thickness?

November 30, 2017

Q. Dear Sir
I want to do copper electroplating on polyurethane foam with more than 150 micron thickness.
What kind of bath solution do you propose? because, Most of copper electroplating solutions are used for less thickness.

Faezehe Barzegar
- Meshad, Iran

December 19, 2017

Q. Hello. I'm just getting started and have done 2 pendants so far. The first one came out great and super shiny. The second next one came out dull! Even after trying to polish and put in tumbler. I did change the anode from a small sheet to copper wire coiled inside. The wire seemed to have a flaky layer coming off it and there also seems to be copper powder moving through solution. The wire and all my supplies are from Rio Grande. I have another in now and it's looking alright so far … but not shiny at all! When do you add brightener? I strained through coffee filter but how often does this need to be done? Also filtering through carbon?

Andrew smith
- Winston Salem, North Carolina

January 23, 2018

Q. I have been playing around with electroforming small pieces of jewellery. I have successfully electroformed a ring and some earrings onto metal. I then tried out a conductive graphite paint specifically made for electroforming and it is not receiving the copper correctly.

My graphite paint test was on a leaf. It was first sealed with acrylic sealer that came from the same company as the graphite paint, left to dry for 24 hours (as stated in the instructions) and then the graphite was applied. The graphite paint seemed to pull the sealer off and leave an uneven finish in places. I left the paint to dry for another 24 hours (again, as instructed) and put it in the bath using the same method and amperage as my successful tests onto metal previously. The graphite seemed to come off into the solution a little and I could see little floating clouds of copper after a short while. After 10 hours (a lot longer than I had left the first test for) I pulled the leaf out and only a small amount of copper had transferred over and only where the conductive wire was directly touching and areas next to it.

My set up is as follows; Rectifier set at ~ 0.3 amps and 0.7 v; positive wire connected to a copper pipe resting across the bath with 1 mm copper wire hooked on with object to be electroformed fully submerged. Negative wire connected to two copper pipes in the bath. Looking at some diagrams I think I may have my positives and negatives the wrong way around. Is this detrimental to the process? If so, why was I able to get a successful test directly onto metal?

My real question is, what am I doing wrong. I believe that the paint and all of the chemicals are of good quality and I feel that the process isn't working due to my lack of knowledge. Is there anything in my process that screams out?

Looking for any advice.
Thanks in advance.

Min Cawthorne
- Bristol, Somerset, UK

May 9, 2018

Q. I have had success electroforming pieces in the past, but recently when I have been putting a piece in the bath the copper will only collect on the copper hook I have attached to my jewelry piece and not the piece itself. My jewelry pieces often consist of crystals coated in graphite paint.

I have an electroforming tank with a copper solution that I made myself:
For 1 gallon of distilled water-
32 oz. Copper Sulfate
32 ml. Sulfuric Acid
10 ml. Brightener

I'm not sure if this is my problem, because I have successfully plated pieces before with this solution, but I can't think of what could be the problem because I have not changed anything else in the process.

Any help is appreciated, thank you!

Kara Cimmarusti
- Chicago,Illinois, United States

Can electroplating rectifier be used for electroforming?

July 7, 2018

Q. I have access to three "old" Vigor electroPLATING controllers. Can these be used for electroFORMING? If so, what should I know about cross-purposing them?

Jann Greenland
- Little Rock, Arkansas USA

July 2018

A. Hi Jann. If they are in working order they should be fine. The biggest difference in electroplating and electroforming is just the name :-)

We call it electroplating if we put a metal coating on an object, for example a truck bumper or circuit board. We call it electroforming if the plating layer itself comprises the object, for example a hollow gold earring formed on a wax core or a stamper for vinyl records formed on, then removed from, the lacquer master. If you're doing a gold flower, some people will call it a plated flower and others will call it an electroformed piece of jewelry.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

July 17, 2018

Q. Hello,
I am hoping to use an older electroplating rig to do some electroforming on jewelry pieces. The problem is, the electroplater has only a single control knob. It has a DC Volts meter and a DC Amp meter, but only the single control knob. (It's an HR Superior 10 Amp Electro-Plater)

In my first test, I had the machine turned up about 20%, the volts showed zero, the amps constantly fluttered between 0 and 2. The copper that was deposited on the piece was flaky and had poor adhesion. The solution also heated up substantially during the process and I'm unsure if that's normal.

Do you have any advice on using this machine for electroforming or do I need to shell out for a more modern device that has independent v/a controls?


Wil Aarons
- Cambridge, Massachusetts, USA

July 2018

A. Hi Wil. Ohm's Law says V = A*R, so there actually is no such thing as independent control of voltage and amperage anyway, although it is true that more sophisticated control systems might let you pick a particular amperage and have the power supply increase/decrease the voltage as necessary to hold it.

It's possible that an old unit is defective, of course, including the possibility that the voltmeter which read zero is broken (you probably only need 1 or 2 volts for your electroforming). But you could start troubleshooting by reading the voltage it's putting out with an external voltmeter. If the solution is heating up (which is normal), it is because of the power the rectifier is putting into the solution.

If you're certain that you have good connections to the anodes and the parts, yet the amperage is jumping all over, it may well be defective. But there are many possible causes for flaky & poorly adhering copper, and the rectifier is not the first place I would look unless there is good reason to believe it is bad.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

July 26, 2018

thumbs up sign Thank you so much for your response! It turns out that my entire plating supply died later the same day I wrote. I sourced a new power supply and my electroforming is now working just as I had hoped.

Thank you again. I am finding to be an excellent resource!

Wil Waychoff
- Cambridge, Massachusetts USA

Need a Rectifier Substitute

August 29, 2018

Q. Hi, I'm interested in starting electroforming copper jewellery but I cannot find a rectifier anywhere. Are there any substitutes for a rectifier?

Dani Putter
- Johannesburg, Gauteng, South Africa

August 2018

affil. link
Plating/Anodizing Power Supply

A. Hi Dani. Your problem is surely not unavailability of plating rectifiers, but language differences such that you are not recognizing that available power supply devices qualify as what people are calling 'rectifiers'. You simply need an adjustable power supply which, depending on the size of your jewelry, can provide perhaps 5 Amps (or probably even less) at about 0-6 Volts (most offer higher voltage, but the lower the better). Good luck.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

September 11, 2018

Q. Hello. I make electroformed jewelry and I make my solution myself. Everything was going smooth till last night. I left the rectifier open on a low current to plate a pendant in a 1L solution. Current was about 0.2 amps and voltage was about 0.3 I think. In the morning most of the piece was plated the way I want but a small part of it was left above the solution (I don't know how but it evaporated more then usual I think).

And the part left outside looked like it was plated a thick layer of textured copper but when I touched it, It just crumbled. Not even crumbled, it was all squishy. Then I electroformed one more piece and same thing happened to the whole pendant. Why do you think it happened? Can someone help me please?

Cagin Ucar
Chitta Studio - Turkey Canakkale

September 2018

affil. link
Trouble in Your Tank: Handbook for Solving Plating Problems
by Larry Durney
from Abe Books
info on Amazon

A. Hi Cagin. When you go from satisfactory plating, to unsatisfactory, keep in mind Larry Durney's 'Logic of Troubleshooting':

"We can safely assume that a working system cannot become a non-working system without some change occurring"

In this case I think you're already 99% confident about what changed: the solution composition -- perhaps due to evaporation, extended run time, or something else. But you've not yet given us any information on that subject. Although it would be nice if people could tell us how to solve the problem of squishy plating from solutions of unknown composition, I don't think that's likely to happen. Get back to us please.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

September 13, 2018

A. Probably too low amount of copper. Maybe iron in solution can be cause too. Try fresh solution. Hope it helps and good luck!

Goran Budija
- Zagreb,Croatia

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