Copper plating steel in home shop

A. Hi MJF. You're certainly welcome to try it, but I don't think it will work.

"Copper crystals" are not a normal part of copper plating to be resolved -- they are in indication of something being done wrong :-)

Luck & Regards,

A. Hi, Bill.

Copper probably isn't the ideal choice because it will tarnish and corrode and become non-conductive (you may have seen green or brown copper roofs). When you see non-corroded copper, it is because it has a lacquer (insulative) coating. Nickel plating is probably a better choice.

You may or may not know that plating jobshops are ubiquitous, and you can probably find an established shop in your area to plate this framing for you if you wish to go that way.

Electroplating as a kids' science experiment is dead easy -- third graders have done the experiments in our FAQ "How Electroplating Works". But robust, functional plating is something else. One issue is that most plating (the exception is zinc plating) is more noble than steel, so if there is any porosity or pinholes at all, the plating causes the steel base metal to rapidly corrode in an effort to sacrificially protect it. This photo shows a nickel plated bar rack designed for indoor use after one day outside.

My advice would be to play around with electroplating if you wish, and have fun (use your copper sulphate and a tiny dash of muriatic acid as long as you already know how to safely handle them) -- but to send your real parts to a plating shop :-)

Good luck and Regards,

A. Hi, Dwain. You are understanding the principle of our electroplating science project instructions, but you are probably not quite understanding the real-world limitations of it :-)

You can force electrons from one pole to another with a battery or rectifier (or battery charger ⇦this on eBay or Amazon [affil links] ) and in this way you can cause metal that is at one pole to dissolve into an ionized state in aqueous solution, convey those ions across the solution, and convert them back to the metallic state at the other pole -- moving metal from one pole to the other. This is very useful knowledge for students, helping them to understand the principles of chemistry and electricity and letting them see it in action -- which is why we prepared and posted the experiment. But, sorry, unfortunately this experiment doesn't put a homeowner/hobbyist too much closer to successfully electroplating copper as a functional coating on steel/iron figures :-)

'Functional' is the operative word. You can't successfully electroplate a functional coating onto steel/iron from a simple salt of copper, like copper sulphate or copper acetate (a vinegar solution) primarily because it will "immersion deposit" (remember the science class lesson where you drops nails into copper sulphate and they copper plate themselves with no electricity) and will have no adhesion. To get a functional, adherent coating you need to start over with a different plating solution (a cyanide copper plating solution) which is far too hazardous for home use, or a proprietary copper pyrophosphate solution, or do nickel plating first. The student plating won't be fine grained, it won't be pore free, it won't be bright, it won't be of consistent thickness, it won't plate onto the recesses of your figurines.

Good luck and have fun, but don't do it to the figures if they are of value to you until you've done a lot of experimentation -- instead send them to a plating shop which can use the proper cyanide-based chemistry for real-world applications as opposed to science class demos. Good luck!

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A. Hi, Prashant. The reason I "went on a bit" was that I hoping to preempt your question -- but apparently it didn't work :-)

You have to switch to copper cyanide (very dangerous) or a proprietary copper pyrophosphate bath -- although a better approach might be to nickel plate first, and then copper plate. As for the amount of current, Faraday's Law tells you how many amp-hours you need for how much copper deposition. You need to use careful temperature control, uniform air agitation, and efficient continuous filtration. You need to forget using scrap copper as an anode material, and buy proper phosphorized oxygen-free anodes. You should get electroplating power supplies with periodic reverse current capability.

It is one thing for us to teach a student to electrochemically move copper from an anode to the cathode as a lesson in chemistry and to demonstrate Faraday's Law, but it's an entirely different thing to apply a thick, bright, adherent, pore-free, corrosion resistant, robust, functional copper coating. It's a bit like showing students how to build clay models of automobiles so they can run wind tunnel tests, and then having them ask what tweaks they'll need to do to those clay "automobiles" so they can drive them on the freeway :-)

An inexpensive and ubiquitous book on the subject is the Metal Finishing Guidebook. It will introduce you to how to do "real" copper electroplating as opposed to a grade school science project. Further, it has tables that do the Faraday's Law calculation for you and tell you how many ampere-hours you need to apply for a given thickness of plating. Best of luck with it, Prashant!

A. Hi, Nishith. No, that is not what I was trying to say. Maybe I could put it this way:

a). Simple non-functional copper on steel plating for the sole purpose of science projects is possible at home, and so easy that grammar school kids can do it.
but
b). Functional copper plating on steel requires poisonous cyanide solutions (which are utterly inappropriate for a home) or proprietary copper pyrophosphate solutions, together with temperature control, air agitation, filtration, phosphorized anodes, proper power supplies, experience, and access to solution analysis equipment.

I am not saying it is impossible to do functional copper plating at home -- experienced and dedicated hobbyists do it (but again, they generally buy proprietary copper plating solutions, they don't use home brew). I am saying again that you can't "extend" our grammar school science experiment on copper plating to use it for functional plating anymore than you can "extend" a clay model of an automobile into a functional vehicle. The level of complexity is in excess of what people would expect, and we haven't yet even talked about the requisite cleaning, acid activation, and anti-tarnish post-treatment.

How thick must your copper be? How shiny, how pore-free, how tarnish resistant? Why do you want to do this?

Please see our Jobshops Directory for plating shops in southern California if you are interested in that route. Thanks very much and best of luck!

I am NOT trying to discourage you from experimenting and learning, but that involves practicing on scrap for some weeks and learning gradually. Expecting to do functional copper plating on the interior of a steel water bottle with no prior experience just isn't realistic. Regards,

A. Hi, Nick. You dad is correct! Rather than plate the steel with a cyanide copper process, an alternative is to nickel plate the steel first, then copper plate the nickel from a copper sulphate process.

So your answers are:
#1: Yes
#2: Nickel
#3: Yes, if plated properly -- but I might doubt that you could learn to do it well enough in short order and with no equipment or training
#4: No
#5: "Straight", yes but not "easily."

But showing through your question, is the belief that you just mix simple chemicals and come up with a simple, safe, reliable two-step process :-)
Rather, you'll need to buy proprietary process chemistry, not mix stuff in a sink. You'll need ten tanks (electrocleaner, acid activate, anti-tarnish, multiple rinses), not two. And you'll be at risk of cartridges jamming in the barrel or exploding from hydrogen embrittlement. Certainly anything can be done if you apply yourself hard enough, but you won't get to the point of sufficient knowledge with internet forum answers; you need to get plating books and study them and mostly put in long hours of practice :-)   Best of luck!

Regards,

A. Hi, Mario.

"Strike" in this context means a thin initial layer of plating.

Yes, it is possible to plate onto steel by starting with a thin coating of nickel plating or a thin coating from a cyanide copper solution or a proprietary copper pyrophosphate solution, and then finishing up with a heavy coating from an acid copper plating solution.

Adv.
Suppliers of these proprietary copper plating solutions include finishing.com's supporting advertiser EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser], but you can also google "hobby plating supplier".

Regards,

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A. Hi Josh. An intermediate layer of zinc will only make the problem worse. If you will read this page to which we have appended your inquiry, you'll have a better understanding of the problem. Make sure the steel that you are trying to plate is utterly clean and free of oxide by scrubbing with pumice powder, rinsing, dipping in muriatic acid, rinsing, then make sure the current is on before you start immersing it, and maybe consider a very dilute solution as a strike, then a more concentrated one for the bulk of the plating ... and that will be the best you can do from a copper sulphate solution. Either a proprietary copper strike, or nickel plating is really the right path. Good luck.

Regards,

Q. Thanks so much. So after reading this it seems zinc isn't the way to go but Nickel plating as a strike/underplating sort of coat then copper will work fine.

Can I nickel plate with a vinegar/salt solution and nickel as an anode or do I need to have nickel sulphate? What does nickel sulphate do that vinegar/salt doesn't or do they do the same thing and allow ion transfer (guessing that's what they do).


Thanks for you help!

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A. Hi Josh. Try both as a learning experience and let us know what happens.

But no, it won't "work fine". I have tried both by explanation and by example to convey that an elementary school experiment with safe household ingredients, which is intended to demonstrate the electrochemical principle of how plating works, simply cannot be extrapolated into robust industrial quality plating that will offer thickness, brightness, freedom from porosity, and proper adhesion.

If you want robust plating you either have to send the components to a plating shop or you need to buy the proprietary plating solutions with their trade secret addition agents, and the filters, heaters, regulated power supplies, air agitation systems, hull cell test equipment, lab equipment, and other equipment associated with industrial quality plating. Then you have to really study. There are books devoted exclusively to nickel plating, books devoted exclusively to plating equipment, books devoted exclusively to troubleshooting plating problems like limited adhesion.

I'm just trying to be realistic, not discouraging. If you want to experiment and learn, by all means try all this stuff! But if you actually need copper plating, send it to a plating shop. You can't build an FAA certified aircraft from children's Lego blocks in your kitchen and you just can't do robust copper plating on steel in a kitchen using child-safe household supplies. But you can certainly enjoy the experiments and learn from them!

Regards,

Q. I guess what I really want to know is what is the easiest way I can with available home ingredients plate copper over steel. I was also just thinking brass -- can I brass plate steel and then copper plate that? Nickel seems like it is hard to get hold of. I want to be able to get hold of the ingredients easily -- seems like copper plating may just be too hard to acquire for steel.

Thanks again.

A. Hi Fahad. We appended your inquiry to a thread which hopefully explains why you are having a problem with this. Can we start with a few questions in return?

- Have you previously done successful electroplating so that you understand the issues of cleaning to a waterbreak-free surface and properly acid activating, or is electroplating new to you?
- Is this "copper sulphate" that you mention just plain copper sulphate or is it a properly formulated proprietary bright acid copper plating bath?
- Is there a reason you can't start / didn't start with a nickel strike or cyanide copper strike?
- What are you trying to do? What does cerium oxide have to do with it?

Thanks and good luck.

Regards,

A. Hi John. I admit that it's frustrating that I can't seem to get across the central point about the problem with trying to copper plate onto steel with vinegar, battery acid, muriatic acid, copper sulphate, copper acetate, root killer, or any kitchen or hardware store chemical you can name -- and it's that copper is more noble than steel...

You can make a battery with electrodes of copper & zinc (the grammar school potato battery or lemon battery), or copper & steel. If you stick a steel nail and a copper penny into a lemon, you make a battery of about 0.3 volts as the copper dissolves into the lemon juice, migrates over to the steel nail and then coats it with copper metal. You can't actually "electroplate" copper onto steel this way because it deposits on the steel without any current applied, and generates about 0.3 volts while it's doing so. The copper-steel pair is itself a battery, it's not a resistance that your power supply must overcome. That is at the heart of why you don't get adhesion -- it just deposits all by itself, beyond your control, as a non-adherent immersion coating. The thing about copper cyanide, or copper pyrophosphate is that they don't form such a battery with steel because the copper is tightly complexed; rather you need to apply power to get the copper to plate.

The best that you can hope for with copper sulphate or any simple salt of copper, is that if you start with a very dilute (very low in copper) "strike" solution, and you apply power before immersing the steel part, you can minimize the "immersion deposit" and thus somewhat improve the adhesion. After it's covered with a thin layer of copper you can then use a higher concentration standard plating solution.

1. Water *will* bead on the steel after brake cleaner. You can clean with a solvent as the first cleaning step, but not the last step. The best pretreatment for very low volume would be scrubbing with a solution of pumice and a pinch of detergent. Then you can rinse with DI water, but otherwise skip step 2 and not worry about the acid.

2. DI rinse only

3. The proprietary plating solution would be best for the reason described: it avoids immersion plating. If you don't want to buy that, then all you can do if minimize immersion plating by use of a dilute solution and hot entry. You can't stop it.

4. Then try a stronger solution of copper sulphate and sulfuric acid for the balance of the plating. You can look up operating conditions in the on-line version of the Metal Finishing Guidebook.

5. Yes, you'll have to manually buff the copper as it will not deposit bright.

Finishing.com has been on the air 20 years now and received a quarter million postings with no hobbyist ever reporting back that they achieved robust copper plating on steel from kitchen or hardware store chemistry. Maybe you'll be first; I hope so! Good luck.

Regards,

A. I have successfully plated copper at home. My mix is a weak solution of copper sulphate made with battery acid ⇦this on eBay or Amazon [affil links] and copper. I added phosphoric acid ("Lime away") and tiny amount of surfactant (dish soap detergent). The surfactant makes the finish brighter.

Current was very low and copper bonded well to totally clean steel parts. Cleaning was by hydrochloric acid and scrubbing with pumice powder. The finish is dull copper but easy to polish. I used electrolytic copper (busbar) for the anode. Current about 1 amp/sq ft. Temp 80 °F. Slight agitation. Immediately after immersion I increased current to 10 amps/sq.ft for under a second then dropped down to the 1 amp/sqft.

Thanks Ron, and congratulations! What is the purpose of the tin plating? An under-layer of copper is not needed.

Regards,

A. Hi Tony, thanks for the kind words. While I am trying to dissuade people from unrealistic expectations and perhaps ruining objects that were important to them, I'm certainly not trying to dissuade anyone from safe experimentation on scrap; to the contrary, we wrote our "How Electroplating Works" experiments for grammar school children hoping they would experiment -- and I hope that adults will do so as well.

Regards,

Great news Dale! I'm not a hands-on plater myself, but I try to be a listener also and to pass along what I hear :-)

A. As a follow up my plating experience I have been having very good luck with Nickel plating. I purchased a polisher and find when I polish the parts they come out beautiful and fast. The prep is where the quality is. I made the simple vinegar, salt solution and used 2 Nickel electrodes. The positive completely dissolved in the solution. I am so impressed how easy this is. However, The prep is so important. You kind of get out what you put in. Polish a screw head, plate it in seconds, and it is bright and shiny. Again I thank you for all you do. Dale

A. Hi Phill. I would say that some of your observations and theories are correct: plating does tend to get "different" and softer as it gets thicker because the copper is no longer struggling to match the grain structure of the steel but builds up ever-bigger, softer, and more porous copper crystals. Thick copper electroforming is possible but it usually requires special additives to control the grain. Your ethylene glycol may offer such benefit but perhaps not as much as proprietaries specifically developed after significant effort.

Actually I see nothing "wrong" with your idea of alternating copper and nickel layers for a backyard enthusiast, but you should start with nickel because copper won't adhere properly to steel, and note that copper is quite soft as a replacement for steel.

Regards,

Thanks for the response Ted.
The plating is inside a cylindrical hole in a tool holder, so will only ever have clamping forces applied to it to clamp it to the tool post, so basically under compression only. I am pretty sure the copper/nickel will survive that situation. Time will tell.
Best Regards.

A. Hi Devanshi. Getting copper to deposit is the easy part -- even 9 year old children have reported to us their successes with this experiment :-)
Getting good adhesion is a much more difficult problem. Make sure your substrate is copper, brass, silver, or gold; copper sulphate plating will not stick to iron or steel, or aluminum or nickel or stainless steel or zinc.
Then dilute the solution, you don't want it saturated. Then, while wearing rubber gloves, scrub the surface with a brush and pumice & detergent until it is absolutely clean, then connect the wiring and put the anode into the solution. Then with the power on, put the cathode into the solution.

The adhesion will be at least much better. Good luck!

Luck & Regards,