Electroetching Metal(s)

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Introduction: Electroetching Metal(s)

Sometimes we find ourselves with the need of making marks on metal, perhaps somewhat intricate marks or patterns for decorative or utilitarian purposes. While there are many ways to mark metal probably the most permanent one is to etch the metal itself, as in removing small amounts of the metal to leave a lasting divot in the surface.

Just as there are many ways to skin a cat there are many ways to etch metal. The most common one is using acids, which for instance is very common in PCB manufacturing to eat away the copper on the circuit boards. This, however, requires handling of corrosive chemicals which oftentimes also cannot be disposed of safely. While completely doable even in a home setting (look up copper/brass etching with ferric chloride for instance) there are better ways to do it, which requires absolutely no dangerous chemicals.

What we need:

Metal, one piece which you want to etch and a sacrificial piece of the same material
Salt, sodium chloride, but any salt which makes water able to conduct electricity should work
Power supply, preferably something which at least could churn out a couple of amps, but in a pinch even a 9V battery works
Resist, as in something which you can cover the metal with to selectively choose where to etch, can be plastic tape or even sharpie marks
A cutting tool, in the video we use a laser cutter, but there's no reason that an xacto knife and a steady hand couldn't be used as well.

And that's it, using these things you can easily utilize the method described in the video above.

Warning and disclaimer

Electricity and water can be a dangerous combination, especially when working with higher currents. Be careful and make sure not to (as I did accidentally in the video) touch both electrodes at once with bare hands

Depending on the material you etch you may release particles into the water which are not environmentally safe, and in some cases may not be healthy for you either. Stainless steel for instance may release hexavalent chromium which is a listed carcinogen, and when etching brass or copper you will release copper into the water which also needs to be disposed of safely (i.e. not flushed down the drain). Look at the alloy mix of the metal you're etching and do your research if it's environmentally safe or not.

Also, make sure that you do your etching outside or in a well ventilated area as it may release anything from minute to decent amount of chloride gas, which can be immediately dangeous to human health as well. With fair ventilation that risk is however removed.

 Hope you enjoy the video, and make sure to subscribe on youtube if you want to keep updated with future updates, as all may not be posted on instructables.

Thank you, and happy etching!

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    45 Discussions

    Great instructable. In November 1968 Popular Science magazine published an article on marking metal with electro-etching. They used a mimeograph stencil, aluminum foil, salt water and a home-built rectified dc power supply. I was in Vietnam at the time and had a new camera, which I promptly marked quite neatly. Let's see, you can still get mimeograph stencils, check; there are still a few typewriters floating around in antique stores, check: and wall warts are clogging our land fills so you probably don't need to wire a home-built! The article (along with everything PopSci ever published) is at http://www.popsci.com/archive-viewer?id=DCoDAAAAMBAJ&pg=154&query=MIMEOGRAPH%20STENCIL

    4 replies

    Not a helluva lot of VN Vets left.Thank You for serving in a sh!tty situation a lot of people didn't want to do!

    Here is another version in Popular Mechanics using paraffin as a resist:

    http://books.google.com/books?id=nNwDAAAAMBAJ&lpg=PA195&dq=Popular%20mechanics%20magazine%20%20electro-etching&pg=PA195#v=onepage&q=Popular%20mechanics%20magazine%20%20electro-etching&f=false

    That's awesome! I love old PopSci articles. It's amazing to see something this simple as being sold as high tech home etching solutions, for hundreds of dollars, right now when you can put it together from things you likely already have in your home. Thanks for the share!

    Simply because the laser is not powerful enough to make a dent in the metal surface. Using more high powered lasers (usually you wouldn't find those outside industrial applications) you could of course mark the metal itself.

    I was going to ask the same thing. Thank you for answering. Great instructable!

    Great video! You did an excellent job. I love the part where you show what could go wrong. I would have totally missed that.

    Great Video Switch and Lever!

    I am currently doing chemical etching for a small project and have gone through many workflows.

    Currently doing the photoresist to create pattern and etching with a ferric chloride + citric acid solution.

    Still not 100% happy with the results but I will keep trying.

    You think I could etch through a 0.5mm plate with this method?

    Best

    photo1.jpg
    2 replies

    I'm sure you could, although I'm not sure how long it would take or how much you'd have to deal with the edges of the etch starting to be eaten away as well. With the tape there's the obvious risk that it would start lifting after prolonged exposure to the salt water, but with the paint (or using a proper resist) that shouldn't be a problem.

    I have work with the photoresist and it has given me fairly good results. Will like to take it to the next level though. Instead of soaking, I will spray the etching solution. It should take less time and reduce the wear on the photoresist.

    Nice.

    BTW, circuit boards are usually made with a non-acidic chemistry. The ferric chloride swaps metal ions with the copper on the board. So it's a replacement reaction that depends on the relative position of copper and iron on the activity series.

    2 replies

    Interesting, I did not know this. I've only seen it done with acidic methods. Thanks for the info!

    Oh, I didn't know there was another process. I guess I only am familiar with the radio-shack kit :) I've seen board houses that use multiple tanks, some of which are acid for cleaning. Didn't know they etch that way, too. Maybe the ferric chloride method is just safe enough for consumers...

    Very nice. If I were doing flat work, though, I would have a pan not a cup, and then you could put say a piece of brass screen on bottom of the tank. Additionally you can either mover the electrolyte, (small pump) or move the object. (move hand)

    just like electroplating, as you are etching yes, but you are also plating onto the rod.