Copper Electroplating the Cheap and Safe Way

[A_Steingrube] has posted a guide to his favorite method of copper electroplating. Plating copper onto other metals is popular with the steampunk crowd, but it does have other uses. Copper plate is often used as a prep step for plating other metals, such as nickel and silver. It also (usually) increases the conductivity of the metal to be plated. [A_Steingrube] is using the copper acetate method of plating. What is somewhat novel about his method is that he chose to make his own electrolyte solution from household chemicals. The copper acetate is created by mixing distilled vinegar and household hydrogen peroxide in a 50/50 ratio. The mixture is heated and then a piece of copper scouring pad is placed in. The scouring pad is partially dissolved, providing copper ions, and turning the solution blue.

The next step is to clean the material to be plated. [A_Steingrube] uses Cameo Aluminum and Stainless cleaner for this, though we think any good degreaser will work. The actual electroplating process consists of connecting a piece of copper to the positive terminal of a 6 volt battery. Copper scouring pad is again used for its high surface area. The material to be plated is connected to the negative side of the battery. He warns to keep the solution and the material being plated in constant motion to avoid heavy “burn spots”, which can flake off after the plating process. The results speak for themselves. As with any bare copper material, the electroplated layer will quickly oxidize if not protected.

40 thoughts on “Copper Electroplating the Cheap and Safe Way

  1. Finally an easy to follow tutorial for electroplating that uses household materials! I tried doing some electroplating some time ago with a hacked up PC power supply, it seemed to kind of work, but it took a long time for a coat that rubbed off by finger pressure alone. I’m going to have to try again now following this tutorial

    1. I’ve seen some videos on Youtube and some suggest that a higher voltage does not equate to better plating results. People seemed to be using voltages in the 1.5 to 3 volt range to me with good results. So you were probably plating at too high a voltage for the best results using a PC power supply.

      A lot companies that make copper coated scouring pads must know how to plate pretty good. Because many copper colored scouring pads are only copper plated, not solid copper.

        1. On a PC power supply, the most powerful rail, amp-wise, is the 12v rail, not the 5v rail… On a mid range PSU, the 5v rail typically has the lowest number of amps, followed by the 3.3v rail then the 12v rail (which has the highest if it’s a single rail design)… You typically see about 15-25 amps on the 5v rail (depending on the PSU’s total wattage), which should be more than enough.

          1. Um. Not really. Most PSUs have the power rating printed on the side of the unit. I’ve just dug a spare out of my junk box, & it’s ratings are: 5V @ 30A, 3.3V @ 26A, & 12V @ 27A. Ratings vary, but this is a pretty typical unit.
            Any of those current ratings are more than enough for plating parts of the sizes mentioned in the article.
            I’d recommend using the 3.3V rail.

          2. Unable to reply to the lower comment, so replying here.

            “5V @ 30A, 3.3V @ 26A, & 12V @ 27A.”

            5v @ 30A = 150W
            3.3V @ 26A = 85.8W
            12V @ 27A = 324W
            So, the 12V rail puts out more than twice the power.

      1. The Redox potential of Cu/Cu2+ is only around 0.5V, so you only need a 0.5V potential difference to cause the copper ions to come out of solution. You may need an extra 0.5V to account for the copper being put into the solution, so you’d need something like 1V max.

          1. Resistance is a function of copper ion density in the solution, and the surface areas of the cathode and anode. So using a copper scouring pad lowers resistance, allowing more current to flow.
            Memory check: positive ions are cations, right? Attracted to a [negative] cathode? And the [positive] anode is the copper scouring pad?

    1. It’s fine as long as you don’t spend them or try to pass them off as currency. Defacing U.S. currency is left over from when the value of money was based on the actual metal that the coin was made of. If you damaged a coin, you might reduce its value. Even then, defacing the coin was okay if you didn’t use it as cash afterward.

    2. Yep, I don’t own those coins in my pocket, the Federal Government does. Elongated coin collectors better watch out!

      (just tell everyone you make really crappy jewelery)

  2. Some basic ideas in electroplating are generally that the cleaner the substrate, the better your results will be.
    Also, controlling the current is one of the most important process parameters because plating at too high of a current rate can deposit metal in an uneven fashion resulting in a coating that does not look good or adhere well.

    For example, there is a classic chemistry demonstration where a clean copper object is placed into a solution of silver nitrate. Silver is precipitated as a coating or as needles/lumps/deposits onto the copper object which is partially oxidised, turning the solution blue due to the dissolution of copper ions. Even when this forms a nice smooth coating due to low reaction rates in a dilute solution at low temperatures, it will still form a very poorly adherent silver plating…. It easily falls off at the slightest touch.

    Although many metals can be electroplated there is a reason why getting durable, adherent, and visually bright coatings is such a specialty process that involves lots of study and development. The initial idea that all you have to do is put two metal objects in an electrolyte solution and run some DC electricity to do all these fancy coatings is a miserable oversimplification.

  3. Distilled vinegar and hydrogen peroxide (with salt) is what I use for PCB etchant. (Previously described here at Hackaday.) So I can take advantage of my used etchant and use it as the electroltye solution for this method?

    1. Yes. Because the dissolved copper from your PCBs is still in the solution (and more pure than the copper plated scouring pad he used in this article), so all you would need to do is add something made of copper to the positive terminal of the battery and your piece to be plated to the negative terminal while both are submerged in the solution… Although I’m not sure if the added salt will affect the plating process or not, I don’t think it would be a problem, but then again, I’m no expert on the subject…

  4. best plating = cleanest substrate, lowest current density, lowest electrolyte concentration, and lowest temperature, at the lowest workable voltage…..

    Generally speaking of course

  5. How exactly are bullets copper plated? All the videos i’ve seen require the object to be physically connected to the cathode, which results in the portion touching the aligator clips to not be plated. The Rainer plated bullets i’ve used show no signs of being attached to a cathode physically, and I would assume that it wouldnt be cost effective to have a worker physically connect a cathode to each bullet to be plated when you consider they’re some of the cheapest mass produced bullets out there.

    Please don’t bring up bullet swaging, I all ready know about that and dont have several thousand dollars to drop on a swaging press and dies.

      1. They don’t, also it wouldnt be cost effective because they make millions of them, and they are only attractive at the lowest price point. I started googling it and apparently they use a method called barrel plating in which the anode and cathode never touch the work piece. Now I just gota figure out how to modify my rotary tumbler to be able to do this.

    1. I have no evidence to back this up, but I think it’s more likely that they pour lead into a copper shell, rather than copper plating a formed bullet. It’d be a lot cheaper & faster than plating.

  6. Barrel Plating is the correct answer for many mass processed objects that can survive the impacts at any sane process speed.

    One memorable Hack on Barrel Plate for Hobbyshops was using a perforated plastic pipe- belt turned in a trough made from well casing. Connections were made to metal trough and what the designer called “Throw Plates curved around the pipe’s upper surface but below the solution top.
    Apparently the dismal ratio of plate onto parts vs trough was Good Enough if memory serves.

  7. I’m currious about the solution manufacture only. Being an industrial hard chrome plater for several years has taught me everything else I need to know about plating.
    How distilled is the vinigar? Was it tested with a hydrometer or simply reduced in volume to an estimated or random concentration of acid?
    A length of copper pipe may have been a better choice than copper plated squb pad….even with the berylium of the pipe.
    I plan on using clean copper bus bar personally.

    1. I’m currently trying to learn to do this, without much success so far I have been trying a graphie/pva mix, bare conductive paint – water soluble :-( , bare paint mixed with pva, and supper shield graphite paint (evil) – I think the problem that I am having is related to resistivity of the coating, combined with the fact that my (electronics) recitifyer doesn’t seem to want to put out much current through the solution when using these type of carbon coated cathodes.
      I know it’s possible to buy nickle/copper/siler paint, so that might be what I try next.

  8. Best thing to use i found is in the hardware store it’s called root killer for you sewer contains .99% coper sulfate*** something but it works well and it’s fairly cheep think I paid 13 bucks for a pound it’s a blue granular I was just using water and a old model train transformer a tight coil of 12gage coper wire for the electrode but I might try the peroxide vinegar tonight I’m sure to get better results

  9. I know a lot of people that copper plate things. I also know some people that say chrome plating might be better in some situations. I did not know that copper electroplating was so popular in Steampunk culture, I might have to look into that some more.

  10. How to plate a non-conductive surface with electroplated copper:

    At one time I owned a printed circuit board manufacturing company, where I made PCBs with plated through holes. The final product involved plating solder, 40% tin and 60% lead, onto fiberglass filled epoxy. HOW?

    1. Clean the fiberglass epoxy board and micro etch in a bath of HCl solution, followed by three rinse baths in distilled water. (Caution: this is an acid solution) The distilled water baths very gently wash off any drag-out solution from the previous tank before placing the board into the next tank. The drag-out rinse tanks are eventually rotated, with a fresh distilled tank as the last bath, and the bath tank that was the first bath, is now condensed and then added back into the active HCl solution tank, where the drag-out came from in the first place. No waste into the environment.
    2. Immerse for a short time in a bath of electroless palladium plating solution. The palladium forms an extremely thin, clear, soft, but conductive surface. (Caution: this is a formaldehyde solution) Quickly, to prevent oxidation as much as possible, you want to get the board into a bath and out of the air, follow by three rinse baths in distilled water. Again, eventually, the tanks are recycled.
    3. Immerse for a short time in a bath of electroless copper plating solution. (Caution: this is a formaldehyde solution) Again, quickly follow by three rinse baths in distilled water. This is a soft, but tightly adhering plate of copper
    4. Electroplate a hard layer of copper. Caution: This is a sulfuric acid electrolyte solution with an amino acid leveling agent and a pure copper anode. Voltage is about 1 volt. Voltage is adjusted to obtain a current that is determined by surface area to be plated and Hull Cell analysis of the particular plating tank. Gentle movement is required to provide proper ‘throwing’ so the plating will plate inside the holes in the board, and not just to the outside surface area. Again, follow by three rinse baths in distilled water.

    The board (or nearly any plastic or non-conductive material) now has a hard layer of copper plating on it. It is at this point that a photo resist is added to the copper coated board. Then the circuit pattern is developed in the resist. This is followed by an electoroplate of solder, then by removal of the resist, then removal of the non-solder plated copper, cleaning the solder plate of oxides, adding a layer of flux to the board, heat re-flow of the solder plating, removal flux, cleaning of the board, adding a silkscreen coat of solder resist and a silkscreen of customer information printing to the board. Then package, ship, and collect the easy money.

    To plate solder, which is 60% lead, a very inactive metal that does not like to electroplate, along with 40% tin, a very active metal, and getting the plating ratios right, means the plating tank contains some extremely dangerous chemicals, such as hydrofluoric acid, and control of the tank chemistry and plating currents is not for the experimenter.

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