Electroplating for a School Science Project

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Q. Thanks for posting my inquiry and the response. I think I will try the immersion method on a few nickels just to turn some heads. I would still like to do the simple electroplating on copper pennies though. My son gets very excited about electricity and batteries and such. In his mind, if a science experiment doesn't use electricity, it isn't science.

So, do you have a simple "recipe" for silver plating some copper pennies? I know you are probably busy and would prefer to receive revenue generating inquiries, but I've looked everywhere and can't seem to find anyone who knows. The local plating shops don't want to give me the time of day, and you're obviously an authority. You are the best contact I've found. Anything you can do would be sincerely appreciated.

Lastly, I think you have a solid web page. Not too flashy (which is good in my book), but it is packed with a lot of very useful information.

Q. My middle-school son wants to do a plating demo as a science fair project. And, yes, I did suggest this based on a demo I saw years ago. what I saw was plating of pennies using a silver spoon as an anode. We were led to believe the bath was simply water, although I now have come to learn that was just a bunch of hooey.

I have followed your FAQ to the point of tracking down some (a couple of tablespoons full) silver nitrate, which, as it turns out, was no simple task!

I've been to the library but the only bath I could find for silver plating didn't specify silver nitrate. Can you provide me with a formula for a small batch (1-2 liters) of solution? Is there anything else I need to add besides the silver nitrate and distilled water, and does the bath need to be heated or is room temperature enough? Lastly, do I need to use a silver source such as an old spoon or coin for an anode, or do I use a copper anode?

Your site has been most helpful, and I really appreciate your response.

Thanks!

A. Hi again, Darrell. You may find me difficult when, for the second time, I suggest that you do an alternative instead of what you want to do -- sorry :-)

... but zinc electroplating looks a lot like silver and it is very easy for you and a 5-year-old to safely do with household ingredients per our "How Electroplating Works" demo page. If you still really want to do silver plating though, read my reply to Dan. Best of luck.

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Electroless Liquid Silver

on Amazon

(affil links)

A. Hi Dan. Virtually all real silver plating is done out of a cyanide based bath, which is a horrible poison and out of the question for a home or school experiment. With silver nitrate you may form a poor deposit -- sorry, but I really don't know :-(

The Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon affil links] says that to prepare a standard silver nitrate test solution, dissolve approximately 17 g of silver nitrate in a liter of chloride-free water, and store in an amber bottle. While that test solution is not really meant to be used as a plating solution, it sounds like as good a formula as any. But if you prefer, you can buy a pre-formulated silver-nitrate based "resilvering bath" from a number of sources.

Silver may not be easily electroplateable from silver nitrate, it may be strictly for immersion plating -- but please let us know what you find. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1997

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Hello ...

I have done a child's plating job with electricity by using dilute cobalt chloride solution from a kid's chemistry set. You can use either a piece of cobalt as the anode (usually not available readily), or a graphite rod out of an old d-cell battery. A 1-1/2 volt battery should do. Agitate the penny while plating. It will at least look vaguely silver to gray.

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Folks,

I suppose I'm just a kid at heart, but I'm one of those irresponsible science showmen who plate silver on things as a demonstration. My favorite is electroless silver plating on glass. It makes a great silver cup from a cheap glass and you can get a kit containing methyl glucamine through LON Lab, or you can use the older formaldehyde method with silver nitrate.

For electrolytic plating, how about showing off the classic woods strike. The recipe is: 1 oz muriatic acid ⇦this on eBay or Amazon [affil links] , 8 oz of water, and 1 oz of Nickel Chloride (often included in chemistry sets). Plate with 3 volts (two 1.5 V dry cells). You can tell the kids that this strike is extensively used in industry.

Good Luck,

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Q. I'm doing a science project, for my 4th grade class, on copper plating and I don't quite understand it, could you please help me?

The experiment book I used says to take a small glass of vinegar and sprinkle in a few good shakes of salt. Then put in some dirty pennies. The pennies are cleaned of the surface corrosion. Then take a iron nail and clean it with 00 steel wool ⇦this on eBay or Amazon [affil links] . Then put it into the glass. After 5 or 10 minutes the nail will be covered with a bright coat of copper.

Can you help me explain what is going on?

Thanks a lot for your help!

Q. I am a 7th grade student, and I am doing a science fair experiment on copper plating. I am looking at a list of ingredients, and it says to use white vinegar, salt, CuSO4, and deionized water for the plating solution. I was wondering two things: 1. What voltage should I use, and 2. Where can I get CuSo4, or can I use different ingredients? Could you please tell me what would be the best plating solution to copper plate a dime?

Thanks

1. A. vinegar in a glass

   Vinegar is a solution of a little bit of acetic acid in water.

2. add salt
   
   Salt is sodium chloride. The water is a solvent that splits the salt into ions of sodium and chloride. The sodium ion has a positive charge, and chloride has a negative charge. Water molecules are lopsided and are positive on one side and negative on the other, something like a magnet. Several water molecules surround each chloride and sodium ion and keep them in solution. If you add too much salt for the water molecules to surround, you won't dissolve all of the salt and some of it will sit on the bottom of the beaker.
   
   
3. add corroded copper (it's not allowed to call them dirty)
   
   Copper metal (that shiny red metal) will react with the salts from your fingers and oxygen in the air to form corrosion products.

   A very thick layer of corrosion on copper has a green color, the color of the Statue of Liberty. (She has a copper skin). This green layer protects the copper underneath from more corrosion and will make Ms. Liberty last a long time.
   The corrosion on pennies keeps rubbing off by being rubbed all day in your pocket and fingers. Even if your fingers look clean, they always have a little oil, salts and acids from your skin. That's why when we touch things, we leave fingerprints.
   
   The combination of vinegar (acetic acid and water) and salt (sodium chloride) dissolves the corrosion products (a mix of copper salts like copper sulphate, copper chloride and copper oxide) into the water. You will now have a few copper ions floating around in the water, and you can see the bright red copper metal of the penny.

4. clean an iron nail with 00 steel wool ⇦this on eBay or Amazon [affil links] and put it into the glass

   You need to clean the iron nail of any oils and rust (iron oxide) before trying to cover it with copper.
   
   Iron and copper are both metals. Iron metal has a grey color and copper metal is red in color. But copper and iron are a little different in behavior. Look around in your classroom. You will see some of your friends who are always jumping around, talking, or getting into trouble. They are like iron. Some of your friends are quiet, and are happy to just sit in their seats and behave. They are like copper.
   
   Copper is happier to sit around. Iron is happier to get into solution in the water. In the glass you have prepared, some of the iron metal from the nail will give up electrons to the copper. This iron will dissolve in the water. The copper which took the electrons will drop out of the water and stick to the nail. If enough of the copper sticks to the nail, you will see the red color of copper metal.

I tried your experiment, but my pennies were not very corroded, so I may not have had enough copper in the water to see anything happen on the surface of the nail.

This kind of reaction is very useful, and is used every day in science and industry to help make the things we use, making our lives easier and more interesting. The things that are happening in your little glass are much more complicated than this, so you must study very hard.

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A. Here is what the Rochester branch of the AESF had been using for years as a plating demo at our annual Engineering Fair: bright nickel plating of pennies. Sure, the setup is not as basic as with copper plating, but no cyanide is required and the plate is bright.

Watts-based bright nickel baths are pretty common in any local bumper plating shop (see your phone directory under "Electroplating services"). Pour some bright Nickel solution in a 1 l beaker [beakers on eBay or Amazon [affil links] , put it on a hot plate, get a small battery or rectifier and, in combination with the toothpaste and toothbrush cleaning technique described above by Ted - you are in business.

Don't forget to rinse the pennies well before and after plating and return the plating solution back to the shop after you are done.

Happy electroplating from PlaterB!

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Q. I am a high school chemistry student who is planning on doing a simple electroplating procedure for the class. I plan on plating zinc onto pennies. This seems to me to be much simpler than using silver. Am I correct in this assumption?

A. I would say yes because I can plate a fairly bright and adherent zinc coating from dilute acetate or sulphate solutions, and I don't know how to do this with silver.

In reading the many letters on this subject, I am starting to believe that any demonstration of electroplating should include a demonstration of wastewater treatment. A nice graphite sponge cathode for electrolytic recovery would be neat.

What good does it do to show someone how to plate, if we don't show the audience that plating requires a carefully thought out and implemented plan for wastewater treatment? Also mention that some plating processes, like chromium plating, for instance, also create a mist hazard for the operator, and this process requires ventilation and scrubbing of the air before release to the environment.

What kind of references do you have in your high school for electroplating?

  
Tom Pullizzi
Falls Township, Pennsylvania
1998

Q. I'm not sure what you mean by references; I have the Metal Finishing Guidebook and Directory. What is another metal that would be good to plate onto copper?

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1998

A. That is a very good reference, I did not expect you to say that you have one of those! There are many formulas in that book, but I don't know how many you can use in the home, since it is a reference for industrial users.

So you have a powerful reference, now you need to control its power and design a good demonstration for high school level chemistry. Have you tried to plate anything so far? What were the results? Have you read the chapters on rinsing by our very own Ted Mooney, P.E., and on wastewater treatment?

  
Tom Pullizzi
Falls Township, Pennsylvania

Q. I'm glad to hear that you think so highly of it. I got it when I interviewed the president of a plating company. I have never even attempted to plate anything yet. I have read the chapter on rinsing, though I admit it got a bit too technical for me, though I'm sure if I had any experience rinsing it would probably make more sense.

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! Idea. Why don't you switch gears, and make your project about... RINSING! The world does not know enough about rinsing. Use your sources from electroplating to expand and expound on the subject of rinsing. Rinsing the soap out of laundry, washing the ice cream out of Breyers' containers. Show your fellow students how much it costs the earth to have clean cars and jeans. Hot water rinses much better than cold water for most projects, talk about the energy cost of rinsing and how it relates to global warming.

It is a revolting subject, this rinsing, because the waste is a very dilute stream of milk, suds, metal ions, petroleum hydrocarbons, etc., but I volunteer you to solve some of our (all too human) problems. I will help as much as I can. Good Luck. - t

p.s. You have plenty of experience in rinsing, now you have to look at the process as a scientist, and understand how it works. Something to do about that law on entropy. If you line up the atoms on one object, you have to disrupt the order of at least that many atoms somewhere else in the universe. Result: pollution.

  
Tom Pullizzi
Falls Township, Pennsylvania
1998

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Q. I also have been trying to help my teenager with a science project. Many of the entries here have been helpful, but are scattered. I have some specific questions:

1.) Can one plate copper using a copper sulphate pentachloride solution?

2.) If so, at what strength, and at what temperature, and at what voltage.

3.) When using old developing solution to plate silver (silver nitrate):

- do I need a silver anode?
- what is the correct voltage and temperature?
- what is the ideal plating target?
- for how long?

All my previous attempts have resulted in a dirty black target.

note: My local camera shop reclaims their silver. It seems to be easy for them.

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A. Yes, Wallace, the thread meanders. That's the nature of public participation, but we do have an FAQ on "How Electroplating Works" that is arranged in tutorial fashion and will be reasonably easy and straight forward to follow.

1. I think you mean copper sulphate pentahydrate, i.e., CuSO₄.5H₂O. Root killer ⇦ this on eBay or Amazon [affil links] is mostly comprised of 'copper sulphate pentahydrate'. This question was answered above with a qualified 'yes' because we can't be 100 percent assured that some manufacturer might not decide to include something besides copper sulphate in the root killer (for example some organic biocide like a weed killer), so read the contents before using.

2. For the purpose of a school science project, use whatever strength you get, run it at room temperature for simplicity, and 1-1/2 volts. As long as it has a blue tint it should work fine.

3. I've never tried that one, but I do know that silver nitrate isn't used for real silver plating (one reason being that the electricity can oxidize the nitrate to NOx-ious gasses. I think the anode material is not critical, and see no reason to heat the solution or apply more than 1-1/2 to 3 volts. But there is a big difference between removing the silver from waste like the photo shop is doing, and producing an industrial quality silver plate. Good luck!

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1998