Metal Plating Plastic Or Metal Parts

Like most of us, [Clem] wants to 3D print in metal. Metal 3D printers do exist, but they are generally way out of reach for most of us garage hackers. As an alternative, [Clem] uses a homebrew electroplating system to get prints with a metallic coating.

The setup is quite simple. Small glass jars to act as the plating tanks and the machine uses an Arduino controller along with a PCB to hold things like a relay to control the 24V used for electroplating. To keep everything tidy, [Clem] designed a 3D printed box that stores all the cables and chemicals when you aren’t using them. Since the parts might get hot, the plastic is PETG.

The trick is that parts need to be conductive in order to use electroplating — typically plastic isn’t conductive. [Clem] paints the plastic parts to grant them conductivity. Graphite paint didn’t give great results. However, an iron-based paint worked better but obscures detail on the print. In addition to galvanization (plating with zinc or steel) you can see copper plating of a nail at around the 12 minute mark, with a plastic plating demo a minute later. The machine can even plate gold using an expensive gold-bearing electrolyte. In the video comments, someone also mentioned that it would be interesting to try plating conductive filament without using the paint. [Clem] tried to remove rust from a big part, but the power supply wasn’t up to the task.

Copper plating is often used as a step to make a part conductive so you can then plate with another metal. In addition to copper sulfate, you can use copper acetate. Sometimes, getting metal into fine details can be tough and it is easier to use a pen to plate those areas directly.

28 thoughts on “Metal Plating Plastic Or Metal Parts

  1. Nice little unit, another upgrade to this could also be a way to reverse the polarity during the plating cycle for a really short time. Often if you are building up a thick layer of plating (electroforming) you can switch the polarity for a few milliseconds to get a metter surface once the base layer has been laid down.

  2. Take a fish tank, put in a metal sheet as a base material, fill the tank with a copper sulphate solution, put a condom or other cheap flexible waterproofing, over a robot arm and add a sharpened copper rod as an end effector, attach it to an adjustable arc welder or say a 40A desktop psu to be the power supply for the electrolysis and then just print away until your hearts content.
    Possible improvements may include, swapping the robot arm for an actual 3D printer and replacing the filament with fine copper wire, if suitable insulation methods can be found for the copper wire before it reaches the extrusion head. Perhaps an oil filled bowden cable design, the oil could be pumped into the cable and then recirculated via a pump as the oil floats to the surface. If the stepper motors of the 3D printer were potted or replaced with a geared brushless design and fitted with encoders, they could be submerged. Alternatively a larger oil layer could be introduced and the copper sulphate solution could simply be a thin layer at the bottom, just enough to cover the print head and work piece.
    That way the electronics would always be under oil. New copper sulphate solution could be pumped in below the oil as the print night increased.
    Perhaps something like aa cheap car windscreen washer pump could be used as the flow rate wouldn’t need to be overly high.
    Note, printing will no doubt take a while for larger items.

  3. Why waste people’s time with this?? He never says what his magical power supply does which differs from a simple bench supply. He doesn’t discuss the actual chemistry. Is he a chemist? What about cleaning and levelers and brighteners and temperature and pH control and all the other necessary details of plating. What about responsible disposal of the chemicals? There is a whole industry devoted to plating. It is not simple despite a few trivial amateur videos which show concepts suitable for a high-school science class, not an industrial process. Having played with this stuff for decades I can relate that amateur coatings in general are not smooth and bright, do not properly adhere, easily flake off and have a host of other problems. There are a few companies which sell proprietary chemistry that mostly works even though it is toxic and expensive. Why are there no kits for doing through-hole plating with a D cell and some vinegar? Because it doesn’t work. Expensive kits that need a lot of effort, sure. Etching a circuit board? Easy. Anodizing is mostly easy. Tin electroless plating mostly works and is fairly cheap. Silver displacement plating mostly works but is expensive and very little use. Actual practical copper and nickel plating, forget about it.

    1. There’s always someone like you in the comment section, it seems.

      Rather than addressing the merits of the content, you immediately exert your “expert” opinion, devaluing the content because you “know better”. Articles like these — while they don’t go into great detail for applications on an industrial scale… because they don’t NEED to — expose people to a process they may not have been aware of. There are MANY people who print miniatures or figurines, or are looking for a way to give a personalized gift a little more flair… I’m sure they’d be interesting in using this video and article as primer. That is, a place to start.

      Next time, instead of bemoaning the content, how about just keeping it to yourself?

      1. Because real electroplating is hard. No point beating around the bush on this one. If there was a remote chance that someone would be successful then I would agree with you, but there isn’t.

    2. You’ll find a lot of this “Can’t do” attitude on the net. What plating forums have sprung up are either directly run by or taken over by plating industry trolls to scare people off from attempting it, and instead drive the business to themselves.

      It appears to be a cut throat industry with a lot of trade secrets, and highly treasured regulatory barriers to entry. One corporate troll threatened to report me to the EPA at the suggestion of pouring a pint of root clear solution down the drain, a purpose for which it is explicitly sold. (And you’re using like a 20th of the “one dose” container in a pint of plating solution)

      I would like to see more of this on Hackaday, however, I suspect it will attract the corporate trolls, and you’ll have an easier time not. But there are scant sources of positive information on the topic as opposed to the negative info.

      I understand that there are dangerous chemicals in some plating processes, one should probably think long and hard about having them in the home at all. However, there are avenues to explore in less toxic alternatives, all of which are often shot down by the “pros”. One can also create toxic chemicals from apparently benign ones (Beware hexavalent chromium) So a good understanding of the chemistry is advised.

      One starting point is older public domain books of “receipts” or as we say in modern times recipes if we’re talking about food. Then you can dig out a number of patents, though as mentioned the business appears to run more on trade secrets. Some mentions will be found in older hobby magazines also of the mechanical and scientific variety.

      And last a few simple things gleaned from my plating adventures… i) It’s not about volts it’s about amps. ii) use distilled water. iii) get anything you want to plate chemically clean.

    3. I watched a fair bit of this video sveral days ago and ended up closing the tab well before the video was complete because it was abundantly clear this was not an actual HowTo and my time was being wasted.

      As for making plastic parts conductive several methods look promising. Electroless nickel is commonly used in industry, sputtering/CVD is always an option (though expensive and not suitable for complex parts), and silver plating mirror solutions should work (Nile Red has an excellnt video on the process:

  4. “Metal 3D printers do exist, but they are generally way out of reach for most of us garage hackers.”

    Isn’t this the point where a HaD reader says, “I’ll build that”? It worked for early days of 3D printers.

    1. there are filaments for FDM printers with high metal content, that are specifically designed to be later put into a high temperature oven, which burns out the organic bits and sinters the metal particles together.
      Yes, the print shrinks by about a 1/3, yes the furnace is not going to be cheap and yes, the fumes coming off of it will be all kinds of nasty…but once done, you’ll have a chunk of metal mostly in the shape you desired.

      1. There’s also another approach where the metal filled print is encased in plaster, and then a lower melting point alloy is allowed to displace the plastic in a kiln via capillarity. It’s not exactly lost wax/pla casting, because the end result is not an uniform alloy and the mould doesn’t need to follow all the rules needed for pouring a cast.

  5. Ive had luck with graphite spray on non-conductive materials. As I recall, I was using a lower voltage though. Something was going badly at higher voltages. I will have to try what Andrew suggested in reversing the polarity occasionally. I was seeing crystals develop rather than a smooth surface if I let it get too thick.

    1. Jack, I have been doing Electroforming of Copper on to all sorts of things for years. Copper plaiting bird skulls, roses etc.. I really should clean up the workshop and do a full on instructable or something as it seems there are a lot of people who are keen on it.

      For the base coat purchase some cheap fine graphite powder from the local hardware store. The stuff used for lubricating locks and bearings works well. Mix it with a cheap acrylic (transparent) paint and dilute with water. I have tried all sorts of mixtures and this was the easiest to make up. Paint it on in really thin layers. Often i laid down about 8 layers then tested the item was conductive with a meter.

      you can also use a slightly thicker version of the pain to fill in some of the gaps and holes but make sure you build up the layers as thick layers tend to crack when they dry. Eventually I got a small spray gun and started using that to speed up the process.

      initially i just used Copper Sulphate made up my disolving copper in to hydrochloric and added a bit of hydrogen peroxide to speed up this process. Then added a large copper plate as the anode (+) power line.

      A constant current source was used and set to about 100/120ma at 12V although I dropped this to 5V and found that the surface became finer and a bit harder. The item was connected to the (-) rail and submesed. you should see some bubbles start to form but if it fizzes then turn the current down.

      There is a calculation used for the size of the object, current consumption and time you leave it in the bath but I usually just went with eyeing the results.

      Switching the polarity for a few milliseconds every few seconds seemed to reduce the crystaline buildup around where the item was connected to the (-) rail.

      Time wise for something like a rose I would plate them for about 6 to 8 hours each. Some were left in over night but keep an eye on the current and adjust it because as the item ps plated it also becomes more conductive.

      Make sure that your Anode is larger in surface area than the item you are plaiting.

      You also get sludge buildup in the bottom on the tank. to fix this I got an old stocking and put the anode in that then every now and again cleaned it out.

      Plaiting other metals was much the same process. Nickel was a bit of fun and made a few walking stick handles this way. Although i purchased the nickel plaiting solution and some brightner as well as some nickel anodes.

      I also had a play with a process called Flash Plaiting, usually this is done on steel. Crank up the current and dip the steel item in and out of the copper solution until it builts up a thin layer. The layer bonds better on to the steel. Once its all covered in copper you can then proceed to the nickel plaiting process.

      Don’t bother trying to plate something that has an aluminium base, the aluminium gets eaten away faster than the metal can deposit on the surface :(

  6. Sugar.
    Plain old sucrose in your plating bath will help smooth copper.
    Instead of moss, you get shiny metal.
    Needing to periodically reverse polarity is a sign your plating conditions aren’t right.
    Long needles, called dendrites, make the plated up metal mossy and can be cause by weak plating solutions and high volts.
    High current, ‘just enough’ volts to drive the electro-chemistry forward, careful control of pH in plating bath, control of temperature.
    Even with all these factors nailed down, it is still an iffy process.
    BTW, common copper wiring is an alloy; not pure metal.
    The alloying metals may not play nicely with the chemistry of your plating solution.
    If you find your plating solutions work for a little while, then go bad, it is the alloying metals poisoning the mix.

    1. Thanks Greg, I may have to try that out next time im doing some copper as im out of brightner. Makes sense as I think the brightner I was using had hydrogen peroxide, sulfuric and glycerol. I suspect they use the glycerol instead of Sugar /sucrose

  7. How about plasma spray? I have seen small rocket nozles – like attitude control – made by plasma spraying titanium onto and aluminum mandrel then etching away the aluminum with sodium hydroxide.

  8. Having worked for 24 years operating a metals cleaning and plating shop at a NASA facility, don’t even try to do plate thru holes. Shipley and LDC companies sell to QUALIFIED companies, not to individuals, as the chemicals are toxic and NOT flushable. Plating to plastic requires an electrostatic charge. The parts to be plated must be “water break free” of oils and dirt, then are plated with a copper tin solution, then the tin is stripped, leaving the part with a charge, then copper sulfate “strike or flash” is plated thin, then the build up copper solution deposits to a useful thickness. A leveler solution reducer in the plating solution helps keep a shiny buildup. Mechanical polishing determines the final shiny finish when nickel plating over the copper, then whatever else you want to plate. Gold and silver cyanide solutions are the best, the silver will drop out over time.
    SO, don’t bother trying electroplating. There is a reason car bumpers cost so much to re-chrome, the EPA and Dept of Environmental Quality with lock you up. Good day, stay safe.

  9. Instead of iron based paint why not just spray a fine coat of glue on the plastic and then spray fine iron powder on the glue, wait for the iron to stick to the glue, knock off any excess and electroplate? I think you could get better coverage in the nooks and crannies and a thinner coat.

  10. Oh and word of warning for those who engage in 3D printing and Slectro plaiting….

    I used to store my chemicals in the same cupboard under the plaiting bath.

    Never Ever Ever put your Acetone anywhere near the rest of the stuff…

    Acetone + Hydrogen Peroxide + acid is super dangerious!

      1. you’ll end up with all kinds of organic peroxides (which are also unstable and sometimes explosive), but TATP is unlikely to be among them, room temperature is an unfavorable condition, among with inorganic acids.

  11. Look up vacuum metallization. It should be possible to make a DIY rig for this. This is how they make those plated plastic parts you see in model kits and flashlight reflectors. Basically you need a vacuum chamber (like a bell jar) and then vaporize a piece of foil which deposits on the plastic object.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.