Growing Copper and Silver Crystals for Art

Usually when Hackaday covers electroplating techniques, it’s to talk about through-hole PCB plating. But did you know you can use the same method to produce beautiful copper and silver crystal structures?

[Fred and Connie Libby] are kind enough to share how they make their crystals that they sell in tiny glass vials you can wear around your neck. The process is simple as you would think; it’s just an electrolyte solution, with a current passing through it, depositing the metal in an ion-exchange. Rather then stop once the part is sufficiently covered, you let the process run amok, and soon large crystal formations begin to emerge. [Fred and Connie] share their technique very briefly, so if you’re looking for a more detailed how-to guide, you can find one here.

Although silver crystals are a bit out of our budget, we wonder how large of a copper crystal could be grown? Large enough to be displayed on a coffee table? Surely such a work of art and science could be an interesting conservation piece in any hacker’s home.

35 thoughts on “Growing Copper and Silver Crystals for Art

  1. ahhh yes now your into my field…the stuff that comes out of this is beautiful…you should also look into extrusion waste from wire making companies same stuff…you can grab a chunk of waste from a wire making company and put it up in your yard as art

        1. Good luck! But if you do find the real mcdeal, sterling silver is 92.5 percent silver by weight, so it might work. But as I mentioned, it’s 20 oz of silver •per gallon•, and according to the instructions you need 3-4 gallons.

          1. I’m not sure why everyone believes it is necessary to follow their “instructions” to the letter. You can certainly do this with less than 3-4 gallons of solution. You may want to use a different shape container to allow room for growth and proper anode/cathode placement. I have done plating in a cheap fish tank before; a pickle jar should be just fine as well; perhaps a jam/jelly jar if you want to go even smaller? That should bring the cost of silver well under $100.

  2. I wonder if those are actually crystals (as in not polycrystaline), or just interesting lumps of copper. The silver ones at least show some signs of the silver cubic crystal structure

    1. I was wondering the same. Places like Alfa Aesar used to sell crystals of different metals and they were incredibly expensive. I dont see them on their site, this was in the paper catalog days.

  3. This is pretty interesting! My real question is there a process to do this with an etchant solution and if so couldn’t you repurpose this to make your own wiring/copper traces?

      1. heat it so there is no water, then add sodium metal. Will probably get super hot. Should make Copper metal and Sodium Chloride. Then dissolve the salt in water, pour, filter, extract. Melt the copper powder into an ingot. This should work because Sodium is much less electronegative than copper, so the Chlorine should favor the Sodium over copper. It has to be “dry” because you don’t want the sodium reacting with water to make hydrogen, and bonding with oxygen instead of the chlorine.

      2. (sorry I accidentally hit the “report comment” instead of “reply” button)

        I have been thinking for a long while about something else, but related:
        A lot of people wonder what to do with their PCB etching chemicals after they are used (solidify? etc), and it would generally be more preferable to be able to use the same solution for longer periods (i.e. until contaminated, instead of too low concentration of unreacted etchant).

        If you place 2 electrode of copper in a copper sulphate solution (really cheap to find copper sulphate), and pass a current through them, then the positive Cu ions dissolve at the positive lead and migrate and settle on the negative electrode. So copper can be moved “without reacting chemically”. From what I have read I am under the impression that it would be hard to control the deposition of copper, especially when there is no electrode yet to deposit on. Also the grain size may be unsuitable. But perhaps removal does not substantially degrade the electrode from which copper is removed. I thought about using blank PCBs (without photoresistive layer), Pressing a kind of semi open mold on it (with gaps where you want copper removed, so the solution can access it, but mold solid -perhaps lined with compliant layer of rubber/latex where you want copper to stay). So press the mold with channels, and perforated channel roofs on the PCB, and selectively “etch” copper away, which redeposits on some negative electrode. So the solution does not substantially change composition, except for trace contaminants on the PCB or in the PCB copper layer. Total charge passed is proportional to volume/mass of copper removed. Resistance should noticably increase when the “large thickness” traces are gone, and etchable area resorts to thinner thickness of copper on PCB when it tries to eat from under the mold, so the resistance while the faradayic conduction happens is a good indicator of when the process is finished.

        1. I forgot to mention:
          * If this process can be perfected, perhaps the molds could someday be 3d printed if the resolution is adequate. And the design of such mold 3d models (i.e. constant perforation density of channel roofs so that the current density is equal across the whole board) could be automated.
          * Since the same solution can (under idealized no-contaminant conditions) use the same solution indefinitely, both ecological and economical cost is much better.
          * No UV and photoresist is necessary.
          * The copper removed is concentrated on the dump electrode, instead of becoming waste.

  4. I was playing with this recently, using copper sulphate from the garden store. Its a very slow process, and the copper denrites I ended up with were too fragile to handle without breaking them.

    If anybody knows where we can get some more detailed info, please post it.

    Here are mine (with some copper sulphate crystals)
    http://imgur.com/dVcqy9W

        1. It was a saturated copper sulphate solution in a tupperwate container. A bit of copper wire dangling into the solution at one end of the container (for the growth to start), and a chunk of copper pipe at the other end. Copper pipe connected to positive terminal of bench supply, and the wire seed connected to negative terminal. Current set to very low. I was playing around with current as I went, so I dont have a value. The voltage value apparently doesnt matter, you just need to keep the current level per unit of surface area of the cathode within a particular range. More current means you get nice long dendrites that crumble like dust, less current means you get little blobs that are a bit stronger.

        2. I read somewhere that a trick to get the current in range is that you dont want bubbles from the cathode. Not sure if this is a real thing or not, but I lowered the current until the bubbles stopped, and it worked ok-ish.

  5. I have been experimenting with this for quite some while and so far it’s seems that time is the crucial factor and also some luck. The lower the current (and not too high voltage on the cell), the slower the crystal growth, the better the results.

    Here (in Dutch) are some examples and how I made them: http://www.amateurchemie.nl/viewtopic.php?f=33&t=792#p6783

    Does this image work?
    [img]http://www.amateurchemie.nl/download/file.php?id=490&mode=view[/img]

    1. Very interesting posts, thanks for sharing.

      If one were interested in doing this at home, where would one get copper sulfate in Canada? Is it found in common household chemicals, or is it something that you have to look around for a bit more?

      Also, are there any examples of how to do this from a complete n00b level (my last Chemistry courses were about 20 years ago… wow just thinking about that makes me feel old).

      Thanks!

      1. I think it can be had in the plumbing section of your local hardware store or even the big box type stores as
        “root killer”. I guess Canada being the 50th state, has all the things we do?

        Where tree roots love to get into your septic system and drains and clog them up. You would typically pour this product into a toilet or drain and flush it down.

        Not to be confused with “stump killer” – which is usually just potassium nitrate or “saltpetre” – that can be used for other things.

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