Copper Electroplating the Cheap and Safe Way

copper plating

[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.

Comments

  1. Jordan Earls says:

    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

    • pcf11 says:

      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.

      • earlz says:

        If I recall correctly, the most powerful rail, amp-wise, is the 5V rail. So, it’d probably be less efficient, but this guy is using a 6V battery, so it should still work at least.

        • m1ndtr1p says:

          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.

      • Zac says:

        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.

        • Eirinn says:

          And resistance?

          • Alan says:

            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?

  2. Joshua D. Johnson says:

    I’m curious if this solution and process would be applicable to electroforming? I know the power requirements are different.

  3. ejonesss says:

    i am not sure about the legality of plating coins since they are federal property.

  4. Wut? says:

    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.

  5. Wut? says:

    I guess what I am saying is that there is a reason that they have long used copper cyanide in industry. It’s not because playing with cyanide compounds is fun.

  6. Joseph says:

    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?

    • m1ndtr1p says:

      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…

  7. Rusty Shackleford says:

    I just use root killer crystals for copper plating.

  8. Rob says:

    keep the dissolved copper at low concentration. The higher the concentration the more likely you are to get a flakily deposit.

  9. Wut? says:

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

    Generally speaking of course

  10. Merlin says:

    Copper chloride will work as well, in fact, I bet that most copper salts would electroplate well.

  11. matt says:

    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.

    • squeeks says:

      Perhaps they attach the electrode to a surface on the inside of the bullet before it is assembled.

      • gripfast83 says:

        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.

  12. Oren Beck says:

    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.

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