Instructables
Picture of Electric copper etching
I was looking a while for a good set of instructions for electric copper etching and found a quite good instruction at Jake von Slatts Steampunkworkshop and decided to refine it a bit and create an own instruction set in german. Now translating it back, i will also provide it here, making it my first instructable...



Here is an overview on what will be neccessary during all the steps:

- a power source ( DC, continuous current ) and electrodes

- an electrolyt ( a conductive liquid ): copper sulphate

- copper as basis material and for the anode 

- some plastic or glas containers.

- inkjet paper

- sanding paper
 
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Step 1: The Method

Picture of The Method
The whole process i will describe is based on an electrolytic bath using a copper sulphate dilution.



Electrolysis itself is a quite easy thing: it is a process, which enforces a chemical reaction due to electricity. What kind of reaction is happening depends on the ingredients being used. 



A detailed description of electrolysis can be found here 





What do i need for the setup?



- a power source ( DC, continuous current ) and electrodes

- an electrolyt ( a conductive liquid )

- copper as basis material and for th anode )

- some plastic or glas containers.





The Power Source

It is a good idea to have a switchable power supply. I use one from Graupner.

It can adjust both current and voltage, so i can vary a bit depending on what materials i use.

I would aim at having at least 12V and 15-20A output.



The electrolyt

A traditional substance for eletric etching of copper and zinc seems to be copper sulfate.

It easily dissolves in water to a nice blue liquid. I used a concentration of 4 parts water to 1 part copper sulfate ( assuming 1 kilo being one litre ;) ). Copper sulfate is defined as an irritant, but can be bought online. The potential danger is that it destroys organisms over a longer period of contact. Don't put it on your skin and do not drain it in the sink.

If you need to get rid of it, contact your local waste disposal dealer.



Copper

Since you want to etch copper, you need to copper object you want to etch. This will be attached to the anode of the power source to let the current run through it. On the cathode you need another piece of copper, on which the Cu2+ molecules can settle.  I actually used brass, also works fine, as will all other materials, that are able to join with copper.





Written in chemical terms, this happens:

On the Anode: Cu => Cu2+ + 2e-

On the Cathode: Cu2+ + 2e- => Cu



The anode dissolves slowly, producing cations, which will transform copper at the cathode through reduction of copperions.
Noa ramot11 days ago

Hi

thanks for the instructable, i owuld like to hear your advise - i would like to copper plate a surface which is organic and then etch it like PCB circute board meaning only few copper line will left - do you think i can do that ? the object is not flat , i was thinking of the follow : 1. cover the organic material with a conductive medium then etching - what i am not sure is if the conductive paint will go with the etching ...any ideas?

JohnCopper (author)  Noa ramot11 days ago

to be honest, i can' tell, since i never tried.
first step, covering any given object, using conductive paint should be "easy". i have seen a few instructables on this page.
second step, defining the parts that should be etched away could be trickier...
what about only painting the actual lines, that should be left with conductive paint and not do the etching, just the plating?

thekendall2 years ago
This may be stupid but how could I etch more than one piece at a time? Just a bigger tank and adjust voltage and current?
0x5c thekendall3 months ago

It should work. I would give a try, but I don't think the result will be the same between plates.

shobo9 months ago

have you tried this method in pcb etching?

JohnCopper (author)  shobo9 months ago
not me personally, but our hackerspace did.
works quite well.
fusion1 year ago
any ideas for harvesting/using the remaining copper? and i can't tell by the pictures, how deep was the etch?
Ramundicus2 years ago
Thanks for posting this. Does the cathode have to be copper or can it be any conductive metal? I need to etch an 18" long control panel and finding a long narrow plastic container isn't easy. I can get a long stainless steel restaurant pan which could work as the container and the cathode but I'd like to be sure that stainless is a suitable cathode material.

Does the distance between the cathode and the anode have any effect on the results or the speed or depth of the etch?
JohnCopper (author)  Ramundicus2 years ago
other conductives will also work, since you can use this method also for copper plating ( look at the comment below ).

so you want to use the pan as container and cathode? i would not do this, since you put a not small amount of electricity on it! you have to use a non conductive material as container.

in general i don't know, ich stainless stell works as a cathode...

the distance does have an effect, it will speed it up, but might also result in increasing heat...
Almost forgot. You mention that the distance between the anode and cathode can effect the speed of the etch. You're using a narrow cathode strip compared to the width of the anode plate. The distance between the two nodes is further at the ends of the anode than at the center. The difference is small but if you positioned the two pieces 1" apart, there may be several times that distance between the cathode and the ends of the anode plate. Have you experimented with that and does that matter?
You may have a point about the amount of current on the metal pan. I got the idea from an etching system I found online. They use a smaller steel pan and a small power supply for etching small pieces. I don't know how much voltage or current it uses but it appears to work, I just don't know how well. It's the only method I've seen that uses a steel cathode/container. (Disclaimer: I have no interest in that company or product, it's very expensive and I'm not recommending it.)

I do like the idea of etching horizontally, though, with the cathode lying on the bottom of the container. I think I can control the distance between the cathode and anode better than if they're vertical.

I plan to use an Xbox power supply that delivers 16.5A at 12V. I'm back to searching for a 20" long plastic container. ;)
ResaJo2 years ago
You know, you can use this process in reverse to actually do copper plating? just reverse the charges from anode to cathode, having coated whatever you want to plate with a electrolytic paint, (even organic things such as leaves, so long as you have coated it completely with a thin coating of wax & then painted it with the paint) and run your bath at a low amps over a period of time and you can "grow" copper onto just about anything.
JohnCopper (author)  ResaJo2 years ago
yep... i know... that's described in this wonderful instructable:
http://www.instructables.com/id/Electroforming-an-Iris-Seed-Pod/
ericCycles2 years ago
When I was a high school student, we used ferric chloride as a pcb etchant. Of course, the solution would become saturated with copper and stop working.

This approach sounds more interesting as it should never become exhausted, copper should be entering and leaving the solution at the same rate. Hmm, however, there would be a problem getting electricity to all the paths, so I guess this isn't something you could use for PCB's.

Thought: could you use an epsom salt (magnesium sulphate) solution instead of a copper sulphate solution? Epsom salts are cheap and easy to come by.
JohnCopper (author)  ericCycles2 years ago
yes, technically is should not become saturated, but after a while, since your material will never be 100% clean, you will have some other dirt in the dilution. it can of course be easily filtered and used again.

i have seen pcbs etched with that method for smd chips, so quite detailed and fine. i do not see, why it should not work, because the paths will form during the process of etching...

i don't know, if it works with epsom salt. i never tried it, so i can't recommend it. i have seen prices vary from 30% ( fishbowl use ) to 200% ( pharmaceutical use ) of the price of coppersulfate. always depends on the quality...
i got my coppersulfate for 8€/kg from ebay... so also cheap and easy...
crysisatutz2 years ago
Please change the words "Anode" and "Kathode" against each other. A Kathode (cathode) is defined as a thing which gives the system electrons. And a Anode (anode) is defined as a thing which take electrons from the system.
JohnCopper (author)  crysisatutz2 years ago
hm.. actually you are right... i guess i mixed that up at the beginning.. thanks for the hint.. will be changed...
friger2 years ago
I like this. Have you tried coating the copper plate in wax and scratching you design into the wax? I did that once to etch aluminum and used copper as the anode.
JohnCopper (author)  friger2 years ago
thanks :)
no i did not try did... for a reason... my skills in scratching wax ;)
designing the image on the computer and just printing it, seemed more usable for me...
hjjusa2 years ago
Will this etch brass also?
JohnCopper (author)  hjjusa2 years ago
yes it should, since brass is an alloy of copper and zinc. the instruction i based this on, was using brass to etch...