Electric Copper Etching

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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

Step 1: 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.

Step 2: Image Transfer

There are two useful methods of transfering the desired image to the copper plate: Photo exposure or direct toner transfer, which saw as the easier ( but maybe more inaccurate ) method i will describe now. 



Before continuing, we have to clean the surface of our copper thoroughly, using rubbing alcohol or other good cleaner. No spot of whatever may be left before the transfer.



Now we need a negative of the image we want to etch. You need to print that on a as glossy as possible sheet of paper. You have to experiment a bit. I chose photo paper for inkjet printers, but i read, that also pages from product catalogs are good. You need a paper, which has a very flat surface so the toner cannot stick to it too good.



Use your iron at a high temperature to first heat up the copper. Then put the sheet with the print towards the copper on the plate and apply it with high pressure of the iron. Take care not to move the sheet or the picture will be messed up. How long you have to press them together depends on the materials used. Again. a bit experimenting is neccessary.



When the sheet is stuck on the plate, put i in hot water for some minutes, until the paper just comes off. After a bit of soft rubbing, the paper should come of completely and only the toner remains.



That was the tricky part...

Step 3: Etching

In this step, you will do the etching ( and waiting... )



You will do the setup described in step 1. The copper plate, that you want to etch has to be attached to the anode using some conductive connector. I used alligator clips, but you can as well just build a small conductive frame, which holds the material. Again some experimenting is needed... Same for the cathode.



The coppler plate has to be covered in the dilution as complete as possible. parts, that are not covered, will not be etched.



When everything is setup properly, power on the power source. I used 15V and 20A as an initial value. If you measure the resistance or the current flow, it will change with time and more power will flow.



Take care, the dilution does not get to hot. Some steam is fine, as long as it is colorless and does not smell. Boiling water will destroy the plate very likely.



From time to time slew the anode plate a bit, that the coat, which will appear after a while, disappears. Try not to remove the toner.



The duration of the process depends on how deep you  want to etch and how much current your power source is able to deliver.

The piece i took for demonstration took me almost an hour.

Step 4: Finishing

Let the dilution drip of well after the etching. Let as much as possible drip back to the container, since you do not want to put it in the sink. Then clean it with clear water. A low concentration of coppersulfate won't harm the environment, but keep it as low as possible.



Use some very fine sanding paper or grinding swart to clean the plate from toner remainders and to get a nice and clean surface.



As you can see on the gun handle, i did not do the transfer properly. There was not enough toner on that line, or it was not well transfered, since it seemed to have fallen off during the etching.



Well.. that' it.. etching done...

Step 5: Addendum

What happend to the dissolved copper? Does it disappear?

No.. it does not... it is attached to the cathode...



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    38 Discussions

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    ArifSae

    2 years ago

    I have noticed , this is only good where the copper is single plane, what about parts separated. Also it leaves copper dust like structure on board (not all etched away)

    I experimented and found these steps to work for me:

    I etched pcb in 2 steps,
    Step 1: etch away all major copper via salt water electrolysis.

    Step 2: etch remaining copper dust via hot Vinegar+hydrogen per oxide + salt water

    pcd etched with electrolysis.jpg
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    Kinnishian

    2 years ago

    Hmm, one thing I'm trying to do is remove copper from some fiberglass boards, without hazardous waste. I like that I could theoretically recover the copper from the solution without much effort.

    What do you think about dissolving my copper board with salt + water + electricity, to a brass cathode. Then, after the board is clean, I just use a graphite anode (non-dissolve-able right?) to collect the vast majority of the copper that is in the anode. I have no idea how much I'll actually be able to collect, though, and whether the remaining water will be relatively safe again. I hope at least to see a visual change. I could theoretically weigh everything out, I guess.

    Sorry I hope these are reasonable questions.

    1 reply
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    JohnCopperKinnishian

    Reply 2 years ago

    as much as i would like to give a proper answer: i just don't know.
    not sure, if it actually works with saltwater+electricity. never tried that.
    i am relatively sure though, that you won't be able to get "clean" water out. there will always be some remains of copper in it, i guess.

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    vergotear

    2 years ago

    The copper plate you etched in your demonstration, what was the thickness?

    1 reply
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    JohnCoppervergotear

    Reply 2 years ago

    hi.. sorry for the late reply...
    if i remember correctly, it was 0.6mm thick

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    Noa ramot

    4 years ago on Step 5

    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?

    2 replies
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    riddlywalkerNoa ramot

    Reply 3 years ago

    conductive medium used in elecroforming was graphite powder - if you can't find that you could reduce a soft graphite stick from an art shop to dust on some sandpaper.....

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    JohnCopperNoa ramot

    Reply 4 years ago on Introduction

    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?

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    rickgravell

    3 years ago on Introduction

    Good job on the instructable. I use half water, half vinegar and table salt to etch my stuff. No precise measurements, just a "gut feeling" on how much salt! lol

    1 reply

    That really works? I wonder if it'll work for electroforming. I'm using a solution with copper sulfate, sulfuric aci & brightener.

    Fascinating! I do copper electroforming for jewelry so I have basically everything I need for this. Thanks for sharing & check out my instructable on electroforming!

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    andreasbra70

    3 years ago on Introduction

    Hey is there an alternative to copper sulphate? Does it just speed up the process or is it a vital component? Copper sulphate is heavily regulated where i am at so i can only get it in ridiculously large portions aimed at businesses.

    1 reply
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    well... the whole point of this instruction is the process with copper sulfate as a vital component.


    i have not made any experience with other methods. i friend of mine uses citric acid. just take a look at other instructables on acid etching. you will surely find something.

    where are you from?

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    UrošP

    3 years ago on Step 5

    that is not actually true, those are not the same ions, copper goes to solution, and from solution to cathode creating sulphate ions... as stated here http://www.greenart.info/galvetch/contfram.htm "In a copper sulphate solution the positive copper ions collect on the negative copper plate, and negative sulphate ions react with the bare metal of the copper anode - oxidize or etch it in fact - and create new copper sulphate. Thus the electrolyte stays at the same concentration, creating the illusion that copper particles are transferred from one plate to the other - a common fallacy..."

    4 replies
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    JohnCopperUrošP

    Reply 3 years ago on Step 5

    Hi UrošP,
    are you stating this, because you have a scientific background or because you read it on this website?
    In any case, as i don't want my information to be wrong, i will check this. Thanks for the hint.

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    UrošPJohnCopper

    Reply 3 years ago on Step 5

    Hello,
    Well, my understanding of this process of galvanization, electrolysis, does come from web, and your post is one of sources from which I gather what I know. I'm not in science and my interest in this is for purpose of making art works, in discipline of printmaking, so I might be wrong myself. It's just that I understood that Cu ions first bond to sulfate, and then from Cu-sulfate they go to cathode, it's not like they are directly transferred to cathode by the current. That's all. And thanks for sharing your work, this post was one of my starting points in this, and it's well made. Cheers.

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    JohnCopperUrošP

    Reply 3 years ago on Introduction

    sorry for the waiting, but i am back with a rough explanation from a chemistry teacher... it's only second hand now, so don't expect scientific syntax :)
    the process starts with the cathode "pulling" the copper ions from the dilution until the saturation gets low enough to retrieve the ions from the copper plate, that should be etched. so yes... they bind to the sulfate to make up the one that were pulled from the cathode...

    but actually... in the end... it does not really matter ;)

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    UrošPJohnCopper

    Reply 3 years ago on Introduction

    hi, thanks for a great reply, it makes it more clear

    but, as I can see, if we go further and ask why is it so, we'll come to things we can't explain (smallest particles, gravity, black matter...), case is that we know what is happening, how to use it, but relations remain mystery so let's call it "the power of love!" :)

    cheers

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    acoleman3

    3 years ago on Introduction

    so, will this etch a copper block deep enough to use as a wax seal stamp?

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    thekendall

    6 years ago on Introduction

    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?