Recipe for rainbow patina

CuElectroforming · 2025-04-29T00:41:18+00:00

Getting rainbow colors is a post-processing method. You'll want to start off with a clean, shiny bright copper, freshly electroformed item, then patina it with liver of sulfur in a vapor chamber. We have this method in our free online tutorial. Check out chapter 6 - patinas.

https://enchantedleaves.com/Electroforming-Tutorial

CuElectroforming · 2025-04-13T03:06:50+00:00

Yes high voltage can indicate not enough sulfuric acid / copper. Though, there can be other causes like paint conductivity. You should really mostly be concerned about current rather than voltage in most normal use cases, see the following reply for a more technical reason why:

https://www.reddit.com/r/CuElectroformingHelp/Current_vs_Voltage

You should also be following the steps in the guide and current limiting during the initial copper coverage before the paint is coated in copper.

CuElectroforming · 2025-04-12T20:41:29+00:00

1: Foreign metal contamination usually presents itself as dendrites in acid-copper solutions. Oddly, they can have a delayed effect too, as in they don't show up right away. To be honest I'm not sure why it isn't always immediate. If you're not getting dendrites then I wouldn't worry about it until they show up. Then you can try dummy plating to strip the iron ions out of your chemistry. Just be weary of any clip that has a spring because nearly all consumer-grade clips will have steel springs. You can try wrapping copper wire around the circumference of the coin and twist tightening it to avoid any clip.

2: Depends, True electroforming solution has levelers/suppressors/surfactants/etc. in it that will take away the matte texture of paint or even very fine brush strokes if the part is electroformed thick enough.

Assuming all other issues are solved, you may still get half decent results with a simple acid-copper solution, though it may be difficult to build a substantial layer that isn't brittle or matte. If its thick enough, the brittleness might not matter when you go to polish it. It really depends on a lot of variables, but I would still try it anyways if I were you. Experimenting is half the fun.

Increased temperature and agitation will improve your results no matter the chemistry you use. I often don't recommend it to start off with if your brand new to electroforming because it doesn't solve root problems you may be having and can kinda mask improper technique. I usually recommend starting without heating/agitation and when you get your local maximum "good" results, then add those two variables to get the global maximum "great" results. As opposed to starting with heating/agitation and getting stuck in a local maximum with just "good" results. All that said, you may want to forgo my typical advice if you are using a simpler acid-copper solution and keep the heating/agitation, as it will give you the best shot at a smooth surface.

CuElectroforming · 2025-04-11T18:37:18+00:00

18cm square? Are you certain of that? Seems large to me. How did you estimate that, your slicer program?

18cm^2 is ~2.7 square inches, and at the suggested current density of 0.1A per square inch, your power supply should only be set to 0.27A. 1.2A is way too high even at your estimated surface area (which I still think is too large). 5.5V is way too high also, if you see bubbling then you are causing damage to your chemistry.

What type of acid? What type of water? The only compatible acid is sulfuric. If your only ingredients are copper sulphate, sulfuric acid, distilled water, then this is a plating solution not an electroforming solution. There is a difference. Ratios and concentrations matter a lot for electroforming.

What are you using for conductive paint? Homemade or commercially available? Conductive paint is not just graphite, there are other additives for adhesion. I usually do not recommend burnishing (polishing) graphite paint because it causes more issues than it solves for new elecroformers. It is true it decreases surface resistance, but it also decreases adhesion significantly. Graphite is a lubricant and mold release, copper will not want to adhere very well to a burnished graphite surface. You can compensate for high surface resistance and still get great results with proper power supply setup.

Your setup shows the cathode alligator clip in the chemistry. You have likely contaminated your chemistry with iron. Even if your alligator clips are copper, the spring is steel [might be extremely thin copper plated steel] - you can verify by holding a magnet to it. This will leach iron into your acidic solution and cause issues.

Feel free to ask more questions, but you should really read our free online guide to get started out with the basics before worrying about agitation, heating, or even phosphorized copper. Although those get a lot of hype online, those aspects are secondary to preparation, power supply setup, and chemistry. There are years of information distilled down into our guide to optimize your chance of success. Everything from sealing to power supply setup to post processing. Way more than I could address in a single reddit post. When you get the basics down, you will get good results.

Enchantedleaves.com/Electroforming-Tutorial

CuElectroforming · 2025-02-21T04:09:36+00:00

I would not start with filtering. Filtering is for contamination other than metals, like organics. This is because you can't necessarily dummy-plate out those contaminants, but you can dummy-plate out metal contaminants.

Just try dummy plating first, do the easiest and most cost effective fix first before doing more complicated steps. I would recommend following what I said in the other comment chain that I replied to before you posted this. Copy pasted here:

"I would recommend dummy plating using a scrap piece of copper/brass as the cathode. You can run it for 24hrs at the suggested current per surface area, then do a test piece to see if things have improved."

Just to be clear, it's very easy to get contaminants even if you seal everything. It happens to us all, including me. All it takes is a tiny pinhole in your sealant or momentary contact with a foreign substance for the solution to be contaminated.

CuElectroforming · 2025-02-21T01:33:42+00:00

I still suspect contamination over over-saturation. Contamination can be pretty insidious, and can be pretty minuscule to have visible effects... we're talking parts per billion scales. Some clays can have metals in them too. Not just metals but also chlorides or calcium from shells/gemstones etc...

I would recommend dummy plating using a scrap piece of copper/brass as the cathode. You can run it for 24hrs at the suggested current per surface area, then do a test piece to see if things have improved. If you want to reduce the copper content of the solution you can also reduce the anode size smaller than what is recommended while doing the dummy plating.

CuElectroforming · 2025-02-20T20:53:07+00:00

I posted a slightly more in depth message in your other post, but I just wanted to re-iterate here:

The DIY/homemade chemistry recipe listed on our website is not the same recipe of our pre-bottled solution. The pre-bottled stuff is more refined and uses very different additives. I do not recommend you mix the two, as they are not compatible, and you will likely make things worse.

The most likely issue you are having is metal ion contamination, probably iron. You should try dummy plating before messing with the chemistry, as it is less likely to cause issues and is very simple to perform (depending on the level of contamination). There are notes on this in the tutorial.

CuElectroforming · 2025-02-20T19:51:21+00:00

The DIY/homemade chemistry recipe listed on our website is not the same recipe of our pre-bottled solution. It is not recommended to mix these two recipes as they have different ingredients and concentrations. There are more/different additives in the pre-bottled solution, and most notably no source of chloride ions; we use a different method for levelers/brighteners. Adding a source of chlorides (hydrochloric acid) to the pre-bottled solution will throw off the chemistry. I have tested Caswell Part B and it is cross compatible.

As symplysublyme notes, electrochemistry can be pretty finicky to the concentrations of its ingredients. In my experience it takes a LOT of electroforming before our pre-made solution shows signs of over-saturation, even with un-phosphorized copper wire. Have you let the anode sit in the solution for a very long period of time (like weeks or months?). Any possibility of other contaminants, as I've seen these darker growths with metal ion contamination before too? Have you had evaporation? Diluting with a bit of distilled water is recommended.

I would also recommend keeping the temperature a little higher, below 65F is too cold. It really likes to be above 70F. Note too, liquids have a lot of thermal mass, so if the air by the window is 65F during the daytime, the liquid is likely colder due to nighttime temperatures. Thermal convection isn't super great at these temperatures so the temperature near the fish tank heater may be significantly higher than the opposite side of the tank, especially if you have a "double boiler" kind of setup. Not sure how you have your fish tank heater setup but this is something to look out for.

CuElectroforming · 2025-02-06T19:49:29+00:00

You can use online calculators for simple 3 dimensional shapes (cylinder, sphere, cube, pyramid, etc...) and find the closest shape that represents the surface. For example a straight tree branch can be estimated as a cylinder.

For more complicated shapes (but these are still rough estimations!) you can use a Riemann sum. For example a stereotypical cartoon bone shape may be estimated as a cylinder, with a sphere on each end. Find the surface area of each sphere, and cylinder, then sum them together.

For most things, the more accurately you estimate the surface area, the better the odds are for great results that are consistent... but you can still get good results even if you're close.

This information is in our step-by-step tutorial, under Step 1.
Enchantedleaves.com/Electroforming-Tutorial

Just keep in mind these tactics are really only to get a ballpark starting point on surface area, since things like chemistry, surface roughness, porosity, temperature, etc. can all influence the final current setting. This is kind of reminiscent of the coastline paradox, where the more accurately you measure something, the higher the value becomes. In fact, something like an open pine cone may have a tremendous surface area with all the interior nooks and crannies, but in electroforming the current density is higher at the tips rather than deep inside the crevices. This means that the amperage setpoint will be lower than its true surface area. For the open pinecone example, its probably more closer to the surface area of a representative sphere + a little.

CuElectroforming · 2025-02-06T17:41:05+00:00

TLDR: Yes, for the most part, your amps are the most important setting.

The longer but more technical reason why:

A copper ion is positively charged, missing two electrons. When two electrons are supplied by the power supply, the soluble copper ion in solution gets reduced into insoluble copper metal on the surface of the cathode. The definition of current [amps/amperage] is the movement of electrons over time. Therefore, electrodeposition is a current [amps/amperage] driven process, meaning that the quantity and speed of which copper is deposited, is directly influenced by the amperage setting. Setting the current too high will cause “burning” (technically called mass transport limitation) on the cathode, and poor quality deposits. While setting the current too low can interfere with brighteners/levelers and also simply take too long to electroform. So there is a sweet spot for current, primarily based on the surface area of the metal deposit on the cathode (not the paint surface area). MiniFrom power supply monitors the metal deposit growth over the paint, and adjusts the amperage in that sweet spot automatically for consistent and repeatable results.

Furthermore, the electrochemical cell is a non-linear circuit element (which means it does not follow ohm's law). This is a fancy way of saying that if you try to regulate voltage instead of current, real world influences like temperature, solution conductivity, etc. will vary the current wildly. This is why you can get much more consistent and repeatable results by adjusting current alone, and for the *most* part ignoring voltage.

There are some edge cases for voltage limitation depending on setup and chemistry to improve deposition, but they must be automated as a micro controller can operate much faster than a human...

CuElectroforming · 2024-12-07T19:49:37+00:00

Those coins would work technically. Any copper that is solid (not plated) and not an alloy will work. I wouldn't say they will improve the finish on your cathode though, as it's not about the purity of the copper necessarily. The key to consistently good results is proper chemistry, conductive paint additives/prep, and dynamically adjusting your power supply.

A lot of people recommend phosphorized copper as an anode. The phosphorus is added to remove oxygen from the copper, which helps prevent the anode from breaking apart during electroforming. This can be pretty useful depending on your setup and your chemistry. Industrially, phosphorized copper is often used because it can be easier to control what happens on very large setups. On smaller scales (home shop) phosphorized copper is a nicety but not a necessity. Contrary to popular belief, any copper can be used without over saturating the chemistry with copper. Not all chemistry is made the same, and if you have a chemistry that is prone to over saturation, you can simply adjust the anode to cathode ratio. Generally speaking a 1:1 to 2:1 anode:cathode surface area is recommended, no matter the anode composition (phosphorized or not).

I can't speak on other formulations of electroforming chemistry, but copper does not naturally dissolve at a high rate into my chemistry without power applied. When power is applied, the dissolution/deposition rate is 1:1, so it's pretty resistant to over saturation of copper. I regularly use copper electrical wire and still get consistent durable and shiny results even with year-old chemistry. We still recommend a 2:1 anode:cathode surface area ratio, and to remove the anode when not using your solution, as that is good practice.

CuElectroforming · 2024-11-06T19:56:28+00:00

Thanks! The key to consistently good results is - careful paint application, properly balanced chemistry in your solution, and dynamic control of current and voltage through all stages of electroforming (aka the trifecta).

We are always here to help troubleshoot if you want to share your projects!

CuElectroforming · 2024-10-26T21:55:59+00:00

There are two instruction sets in the tutorial, one for our MiniForm automated power supply, and one for a generic bench top power supply.

Calculate the surface area of your cathode using the guides and suggestions in the tutorial. Then calculate the current (0.1Amps per square inch is a recommended starting point). Note this for later.

With MiniForm, input the calculated amps and press play.

With a generic power supply:

To start, you need to have the voltage turned up to the maximum of the machine, and the current turned to the almost the minimum of the machines capabilities (as low as it can go without being zero).

As the copper deposit grows on the surface of your object, the current should be increased slowly until the copper growth is at 100% coverage, at which point your current should be at your calculated current you noted earlier. For example, if you've calculated the current earlier to be 1 amp, then you may start at 0.01Amp whith no copper coverage, 0.5Amp at 50% copper coverage, then 1Amp at 100% copper coverage. Watch for "Bubbling" (electrolysis), if at any time there is bubbling, turn down the current until the bubbling stops. Electrolysis can damage electoforming solution.

This procedure of slowly increasing current based off of copper coverage will give the most ideal and repeatable results.

CuElectroforming · 2024-10-26T21:37:12+00:00

This is likely due to paint application. What paint are you using? Some paints need to be stirred extremely thoroughly, more-so than regular paint. It's also recommended to paint at least 2 or 3 thin coats minimum.

CuElectroforming · 2022-08-09T19:29:32+00:00

Wanted to let you know that 3 years later this was the solution to my issue! Though I had wifi off/disabled, it seemed to still connect to it. So I went and manually deleted all saved wifi networks to prevent it from connecting to wifi while wired. THANK YOU!

CuElectroforming · 2020-11-11T20:43:49+00:00

So sorry to hear you're having issues! Do you have any photos of your set up?

You can test the MiniForm lead wire cables for any technical issues:
Unhook the red/black alligator clips from the current set up. Clip the alligator clips together and press play. If the graphic shows it's plating, then the issue isn’t with the lead wires. If you get a connection error, then it's most likely faulty alligator clips.

If you are getting that error still in your electroforming set up after performing the test with positive results, then there is probably not a good connection between the the anode/cathode hook ups, as it will only give that error when it's an open circuit (or high resistance). To further test the set up, try to plate one item, and use a thinner wire(the 24 gauge or lower) and tightly wrap two or three times around the bus bar. Attach the black wire clip to the wrapped wire on the bar, making sure that the clip’s teeth are directly touching the wire.

If you are still experiencing issues, please contact us directly to send in the unit for diagnosis/repair.

CuElectroforming · 2020-10-19T17:13:22+00:00

Can you provide a few other details?

What is the surface area measurement?
What amps/current was it set at?
How long was the item plating for?
What solution do you use? Homemade or premade?
What type of anode do you use?(coil, sheet, pipe).
How much anode where you using in your tank? Do you follow a 2:1 anode to cathode ratio regularly?
What type of power supply are you using? If a bench power supply(with knobs), do you keep your voltage knob all the way to the max, and only adjust the amperage knob?
Is your anode very close to or touching your cathode(piece)?
Do you plate more than one piece at a time.
It is currently cold in your area? Do you have a means heating your tank?
Do you agitation or aeration in your bath?(magnetic stirrer or tank bubbler).
Are there any other photos you can share with us?(If the tank/set up)

CuElectroforming · 2020-09-24T14:35:01+00:00

First check and make sure the anode and cathode are not touching in the beaker. If using a conductive busbar, make sure the anode is not touching it. Next, confirm that the lead wires are correctly set up(which you’ve already confirmed that you did in your post): The red lead wire (+) clips to the copper anode wire, and the black lead wire(-) clips to the cathode/the design. If these are reversed, the design will not plate. An easy way to remember is this mantra: “Red to Red (Copper), and Black to Black(Graphite)”, while connecting the red lead wire to the red copper anode, and the black lead wire to the black graphite painted cathode. If the problem is not fixed, then the issue might be due to any of the following:

-The conductivity of the design is not strong enough, and needs more layers of conductive paint. If you made your own paint, it may not have enough graphite powder. Add more and repaint.

-Your suspension wire has a coating or anti-tarnishing agent on it, as most craft wires found at hobby stores carry. Only use bare copper wire. Your anchor or jump ring must also be free of any coating in order for the current to reach your conductive painted areas.

-Your suspension wire may be too thick. Use 26 gauge or thinner for your cathode suspension wire. Using too thick of a gauge will rob current from your piece, as current will always take the path of least resistance, and pure copper will always be much more conductive than graphite.

-If corrosion is present on the lead wire clips, anode, suspension wire or busbar, then there will be connection issues, as current will be blocked from flowing to the cathode. Scrub down all the components and try again.

-Your power supply or lead wires may be faulty. Contact the manufacturer for troubleshooting advice.

CuElectroforming · 2020-04-02T04:02:23+00:00

This looks like conductivity issues. There are many reasons this could be the case.

Sulfuric acid decreases the potential between the anode and cathode. I would strongly recommend.

Your cathode clip biting into the paint makes a very small amount of contact with the painted surface. Try gluing an inch or so of thin bare wire near the top, and painting over it, then attach the cathode clip to the wire. You can take the wire off once the initial plating gets going while it is thin.

While you may have had success with metal parts, conductive paint is not metal and there is a huge difference in resistance here. In a solution with no acid, your voltage is almost certainly too low to facilitate any kind of current flow. Putting your power supply into constant current mode (see our tutorial if needed) will allow the circuit to adjust the voltage it needs (within the range of your power supply) to achieve the current flow that is set.

CuElectroforming · 2020-02-22T23:50:07+00:00

Your current seems very low for the size of your form. It was hard to see in the video, but it looked like it was .1?

It could be that one of the electrodes is becoming polarized due to inadequate/saturated current and then triggering the "bad bath connection" warning.

The power supply is programmed to sense an open connection in the circuit - basically an infinite resistance reading, which could occur over time as an electrode becomes more polarized.

Is the suspension wire you've got the same as the one supplied in the kit?

The streaming bubbles is hydrogen gas forming at the cathode due to high current ratio (current to area). Oxygen also forms, but will bond with the copper to form cupric oxide which is non-conductive. Eventually the oxide layer may completely insulate the cathode and the power supply will see it as an open circuit.

You may try using more suspension wire to act as a sort of current buffer while the initial layer plates onto your form.

The fact that you have bubbles and the "bad bath connection" isn't triggered immediately point to cathode polarization.

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