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Acid Copper Plating brightener / additives

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Current question and answers:

Q. I am working in an Organization where I have to look after Acid Copper Plating process without any additives, maintaining the deposition around 300 microns. My questions are --

1. During the process a huge amount of copper sulphate is generated, which is not taking part in metal deposition.
I have to take out some solution and dilute the bath solution to maintain copper sulphate concentration at 250 gm /ltr.(maximum). This is huge loss. How to stop this generation of copper sulphate, so that the bath efficiency would be increased?
2. If my issue is solved, if the conductivity & pH are measured and corrected., in that case what should be the range of conductivity and pH?

Rathin Mukhopadhyay
- Kolkata, West Bengal, India
May 26, 2022

A. Hi Rathin. Thanks for the question but it remains very difficult to properly answer because there is very little context. This is very thick plating: What are you plating and why? What sort of special properties are expected of this plating? Brightness, small grain size, freedom from porosity are not required? Or are they? Why can't any additives at all be used? Are you familiar with and using phosphorized anodes? Thanks.

The anodic efficiency (dissolving copper) is greater than the cathodic efficiency (plating out copper), and that is why the dissolved copper is increasing. Additives might help, optimized anodes might help, some inert anodes might help, pulse plating might help, but please give us more info on what you are trying to do and why. Thanks!

Luck & Regards,

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

Q. Dear Ted,
Thanks for your early response. Now, I am going to elaborate a few points as per your query :
1. I electroplate Earth Rod / Ground Rods. This is a process of electro copper deposition on steel Rods (MS) of different dimensions like - 1/2 inch X 8 ft, 5/8 inch X 10 ft etc.
2. I don't need extra brightness. Porosity is not my issue but of course grain size is a big issue. I am continuously trying to reduce grain size as much as possible.
3. Yes, I am very much familiar with phosphorised copper anode - I am maintaining it at about 0.04%.
4. Since my system is non-bright, I don't think additives are necessary. These organics make more issues.
5. Bath solution consists of Copper Sulphate, Sulphuric Acid and Chloride (60 to 100 ppm). Adequate air agitation and filtration are provided. Operating Current Density -240 amps/sq.ft (maximum).
What I am trying to do is very clear - to stop / minimize generation of copper sulphate in the bath solution during electroplating process.
And why - to increase bath efficiency.
Now, I need your valuable opinion that is the issue is solved by knowing and adjusting the conductivity and pH of the bath solution?

Thanks & regards,

Rathin Mukhopadhyay [returning]
- Kolkata,West Bengal, India
May 27, 2022

A. Hi again Rathin. I have not operated a copper sulphate bath, so all I can offer is book learning, but they all seem to note that the anode efficiency is greater than 100%, so the problem cannot be completely stopped, so the best defense is to keep cathode efficiency as near to 100% as possible by maintaining copper and acid concentrations near the middle of the operating range 20-32 oz./gal and 6-12 oz./gal respectively; keep temperature slightly warm, about 90 °F, and make sure you have very good agitation so there is never any copper starvation at the cathode. Since chloride aids in anode corrosion, you might try to reduce it. I assume you are plating onto an underlayer of nickel plating?

Readers: We have several threads about copper plating of steel earth rods / ground rods here, for those readers with an interest in that subject, including "Copper vs. Galvanized Steel Ground Rods /Earth Rods" and "Copper plating steel grounding (earthing) rods"

Luck & Regards,

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


Q. Dear Ted,
Thank you very much for your attention to my issues.
In reference to your suggestion I would like to mention that we have already tried with pulse plating, graphite and titanium as anodes but my issue is not solved.
Would you please suggest any additives to solve the issue?
Do you think conductivity of the acid copper solution and its pH may be a part of the issue? I seek your valuable opinion.

June 24, 2022

A. Hi Rathin,

There is little you can do to stop the creation of copper sulphate, as Ted said the anode efficiency is greater than 100% so copper will dissolve into the solution more readily than it plates onto the job.

However, the addition of an insoluble anode (titanium or preferably platinised titanium mesh) connected to your anode rail will encourage plating out of solution rather than dissolution of your copper anodes, reducing the copper sulphate concentration.

You won't always need the insoluble anode in your tank, it'll take some experimentation to figure out what the best procedure is and how often you will need to use it depends on how quickly you form copper sulphate (current, plating time, solution chemistry etc.) but this will certainly be better than having to throw away high copper solution.

All the best,

Dave Kay
- Manchester, UK

A. Hi again, Rathin. The only additives that I know of shield the cathode, thereby possibly even slightly decreasing cathode efficiency, accentuating the problem.

I believe that Dave Kay has the best idea, experiment with platinized titanium anodes, even though expensive. To my knowledge a plain titanium anode will not conduct current in this situation and would instead just increase the current density on the remaining copper anodes, not helping with 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:



^- Sorry, this RFQ is outdated
     View Current RFQs

Q. Hi,

I need to know what kind of organic additives (brightener) I should add to a copper electroplating bath, Using CuSO4.5H2O, HCl and Sulphuric Acid. Well it should use the Lea Ronal copper Gleam PCM+ though, but since I live in small city where is impossible to get that additive.

So my question: Is it possible to replace that additive using other chemical?

Toxadhie Riza
- Malang, Jatim, Indonesia

"Electrodeposition: The Materials Science of Coatings and Substrates"
by Jack Dini
from Abe Books

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A. Hello, cousin Toxadhie.

According to Jack Dini in "Electrodeposition: The Material Science of Coatings and Substrates" .
common brighteners for acid copper in the old days included "glue, dextrose, phenolsulfonic acid, molasses and thiorea".

Dini goes on to re-quote Reid from 'An HPLC Study of Acid Copper Brightener Properties' as follows: "Carriers are typically polyalkylene glycol type polymers with a molecular weight around 2000, levelers are typically alkane surfactants containing sulfonic acid and amine or amide functionalities, and brighteners are typically propane sulfonic acids which are derivatized with surface active groups containing pendant sulfur atoms".

The vendor obviously expended years of expensive research effort to get from the above-described general idea to their specific formulation, and if you don't or can't license their process, you are limited to working with the generic materials and settling for a less satisfactory result, or expending significant expense yourself in duplicating the R&D efforts of the process supplier.

You will presumably not have access to HPLC analysis and expert interpretation of the results, so plan on becoming a Hull Cell Master :-)
Best of luck,

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

Q. Dear Ted,

My boss asked me to do some research into this area. Would you please give me a list of reference articles regarding the organic additives used in acid copper plating, their functions and major mechanisms of enhancing plating quality?

Many thanks,

Haifeng Zhang
- Allentown, Pennsylvania, USA

A. Hi, Haifeng. You can try scholar.google.com, but I think the best thing is to contact Metal Finishing Information Services in Birmingham^Warrington, England about getting a copy of their MFIS CD-ROM if you can get access to the articles it abstracts, or contract them to do the search and copy the articles. It isn't legal for me to use my copy of the CD-ROM to do a lit search for you, but one promising article looks to be: "Acid Copper Sulphate Plating I. Simple Addition Agent Control" by Mohler J B; Metal Finishing magazine, June 1987, pp 121-122. Good luck!

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

A. Hi Ted,

MFIS appear to have moved to Warrington (England). Here is a link to their website:


Jon Light
- Saltum Denmark
December 21, 2015

Q. Hi Everyone,
We have a handful of acid copper plating tanks (copper sulfate, sulfuric acid, chloride ions), and the leveling solution we've been buying for the last 10 years is no longer in production. I always prefer to make my own materials whenever possible, and I'd like to start preparing my own plating additives.

I've been reading a number of studies on thiourea and copper deposits in acid copper plating at quantities of about 0.017 g/L, which I will start testing in the coming weeks. An old electroforming friend of mine also suggested polyethylene glycol, which I've been reading up on as well. Does anyone have a ballpark figures on how much PEG to use? Or any other advice or suggestions?

All the best,

Gaelen Armstrong
- Fairfield, Iowa
December 9, 2020

A. Howdy Gaelen,

PEG is a chain so typically there's a molecular weight of the chemistry you buy. This weight is going to play a role in how much you would use. On top of the molecular weight of the PEG the ratio of your chloride to the volume of PEG is going to be important. I can't give you an exact number as I don't know what type of deposit your shooting for, but some general guidelines is smaller MW compounds need higher g/L large MW compounds typically need less.

Depending on other additives will change how much you will need Patent US4430173A uses 10-100g/L with 9k mw

Studies on Anisotropic Electrodeposition of Copper
with Organic Additives uses 300 g/L with a 3000 mw

Hopefully this gives you a good starting point. There plenty of online studies which use a range of different chemicals for carriers, brighteners, and levelers.

Good luck!

William Hogan
- Sidney, New York USA

thumbs up sign Hi William,

Thank you very much for your reply. The 9th was my birthday (the grand ol' 36th) and you made my day with what you wrote back : ) It's a great starting point, and just what I was looking for.

We're electroforming over some highly textured and complicated molds a little 36"-41" across about with 1" variations of depth ... I'll keep reading patents and materials about thiourea and PEG - thanks for pointing me in a good direction.


Gaelen Armstrong [returning]
- Fairfield, Iowa
December 23, 2020

Readers --

• please see also Thread 11172, "Preparing acid copper brightener"

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