This is a technique that has been used by humans for a very long time.

Learn how to create a deep electro-etched metal plaque with household items or items from the hardware store in this Instructable.  There are no hazardous chemicals (except dihydrogen monoxide and salts of sodium and chlorine), no dangerous voltages, and no toxic chemicals to dispose of.  Be aware that the metal that disappears from your etched metal does end up in the water, so you will need to pay attention to any local laws about disposal of metal particulates.

This is a great technique that makes it really easy to go from virtual artwork of any type to a dimensional 3D surface.  From there you can use it ti burnish and emboss paper, create molded items, make stamps, steam punk data plates, or anything else where you need to have 3D art from your 2D computer graphics artwork.

In this sample project, I will be creating the plaque from a 1/8" rectangle of brass as shown in the second photo.

So read on if this is something you would like to be able to do yourself.

Step 1: Here's What You'll Need

You will need the following items and supplies:
  • Piece of brass, bronze, aluminum, steel or stainless steel, or any other metal
  • Vector graphics program or other program to create the art for the CNC vinyl cutter
  • CNC vinyl cutter
  • Self-adhesive vinyl sheet for the vinyl cutter, any color is fine
  • Tub large enough to hold your piece of metal
  • Salt
  • Water
  • Battery charger or charged car battery (or other similar DC power supply of 5 to 10 amps or more)
  • Wires to connect the power supply to the piece of metal
  • Sacrificial piece of metal (preferably stainless steel, but any metal will work)
  • Electrical tape


<p>Rapid bubbling means you are disassociating water. I use 5v from a pc power supply for my etching. I like to use an electrode that is as large or larger than my etch target. Things like proximity, solution concentration, total amperage all make a difference on etch speed. My setup is basically a copper grid electrode that sits 2 inches(5 cm) from the target face. I also use copper sulfate as my electrolyte, but I only process copper materials.</p><p>Also, for those in the US anytime you do electrochemical etching or plating your waste water is epa regulated. </p><p> Stainless steel is particularly bad as the electro-etching converts the chome to hexavalent chromium which is nasty nasty stuff and should never be put down a drain.</p>
<p>Is hexavalent chromium created only if steel is the target of the etching, or does it also apply if it is used as the sacrifice piece? Is it a vapor, a sludge?</p>
<p>The chrome in question is only a product of electrically dissolving Stainless steels. Stainless is a combination of steel (iron and carbon) and chrome. So when etching away stainless the chrome dissolves into solution making it soluble and toxic. So not a gas, some in solution and some as sludge once the solution is saturated.</p><p> And only if etching stainless is it going to liberate chrome. The sacrifice piece gains metal from the etching piece so you would be plating the stainless which is fine.</p>
<p>Thanks! So, I do electro etching of bronze in Cupric Nitrate (hoping to switch to saltwater, but not sure it works on Bronze) and I am using a piece of Stainless Steel grate as the Cathode/Sacrifice... and that piece of Stainless is dissolving gradually!... it's not accumulating metal, as one would expect, it's getting covered in what looks like rust, and falling away around the edges. Any ideas why, and do you know if this might contain hexavalent chromium? Sorry to be such a pest, but there are so few people out there who have knowledge about this. Thanks again! </p>
<p>Well if the sacrifice screen is dissolving in the action its probably safest to assume the chrome is being liberated and this material should never go into the water table. When you are done with the liquid either dispose of it at a proper facility(preferred) or let it dry out to powder and store the solidus in a sealed container. This is safer than the liquid but should still make its way to a hazmat disposal facility.</p><p>What I would expect is happening is the tin and copper are depositing in a &quot;sponge&quot; structure which is delicate and will fall off. CuO is red and deposits in soft layers. If the screen itself is actually dissolving away slowly the chrome has to go somewhere. What % is hexa chrome(VI) or is still chrome(IV) I wouldn't be able to tell you, but I treat any electrochemical solution as hazardous just to be on the safe side (of the law).</p>
<p>Amazing info, thank you. (I'm unreasonably excited to have found someone who knows what they are talking about with this stuff.) :) I think you are correct about the tin and copper collecting in a soft layer, as it flakes off when removed and dry... but the stainless is also definitely eroding away. There is a black sludge in the bottom of the Cupric Nitrate after several etches, which I strain out and remove using mask/gloves/goggles, etc.; and I have never put the stuff down the drain, I've been collecting it in paper towels and storing in a kitty litter jug until I could take it to hazmat because I dont know what it is... Do you think this black sludge could be hexa chrome?</p>
<p>Some portion of it could be, but the bulk is probably mostly oxides of copper and tin. I mean lots of brass etched, vs a little bit of stainless dissolved.</p><p>You could use a test (some strips are &gt;30$) if you are just trying to find out if you are making the carcinogenic genotoxin Chrome(VI).</p><p>I would just assume that all elctrochemical solutions are toxic. </p><p>Actual businesses doing electroetching/milling/plating can be legally quite a bit more polluting than your home shop could achieve, so this is really an exercise in being a good citizen/neighbor. </p><p>Regulations for wastewater of electro-finishing businesses in the US appear to not care about the chrome content till you are pushing more than 10k gallons of water a month or more than .58mg/l. *I am neither a lawyer nor a business consultant so your experiences with the law may vary.</p>
<p>Ah, well that makes sense, and no worries about the legal stuff; I'm a hobbyist and just want to keep myself safe and of course, I do not want to harm the environment either. I had not heard of &quot;hex chrome&quot; before seeing your post here, so I am glad to have learned about it. I think a lot of hobbyists who do electro etching (studio jewelers, mostly) do not treat these byproducts with as much caution as they deserve, because it seems benign compared to acid etching waste. Okay, one more chemistry question, not sure if you can help: I use Cupric Nitrate, not salt water, in my electro etching. Cupric Nitrate can be used again and again as long as it is strained occasionally (which is why I like it); other etchers have claimed to have restored their Cupric Nitrate to it's original &quot;clear blue&quot; by simply straining it through coffee filters. (Nope. The solution continues to look like muddy river water.) Do you think there is a need to strain it more thoroughly? Visually, the solution looks like it needs to be cleaned, but I am not sure if it is necessary for it to continue to serve as an effective electrolyte. I've been looking at buying a lab filtration system like this, but I am not sure if it is necessary: http://bit.ly/2eUm274 Thanks, you are my hero. :D</p>
<p>Thanks for this! Have you tested salt water on bronze? I have read that it does not work on bronze, so am curious if you've tried it. Thanks!</p>
<p>Want to let you know that I did actually get a much better etch than I thought before I cleaned off the resist. It took two hours, but the voltage was low, and the salt solution had been used before. </p><p>I mixed up a new batch of salt water today, much more saturated, and got a new charger. I'm going to try it tomorrow with higher voltage. </p><p>I want to clad small gift boxes for the children for Xmas. I always bite off more than I can chew. Maybe only my two grandkids will get them this year. Anyway, the flashing I bought from Lowes is thin and cheap, so I can experiment. The only expensive part is the p&amp;p blue. They are worth it, though!</p><p>Want to say thanks!</p><p>I</p>
<p>I have used this process with great success on copper and brass, but when I tried exactly the same process on aluminum, I got nothing at all. Do I need a different salt solution for aluminum?</p>
<br>Hi CVC...<br><br>You can use this technique with all metals including aluminum, using the same salt solution and power.<br><br>One of the first projects I did with this was the embossing die I made that we used to put a raised TechSHop logo on the very first gift certificates we sold. Those are probably collector's items now...we have been open 10 years as of this Saturday Oct 1, 2016! (Be sure to come to our open house party if you read this message in time and you live near any of our 9 TechShop locations in the US!)<br><br>Anyway... <br><br>I suspect that your aluminum is either:<br><br> o Anodized<br> o Coated with plastic or lacquer or some coating<br> o Heavily oxidized<br><br>All these conditions will make the surface non-conductive, and electricity will not be able to pass through the metal's surface.<br><br>The best way to check this is to see if the surface you are trying to etch is electrically conductive. You could do this with a digital multimeter, a battery and a lightbulb or LED, or even just take your two electroetching power leads and touch both of them quickly on the surface of the aluminum and see if you get a little spark.<br><br>Anodized aluminum is actually a layer of aluminum oxide formed on the surface of the aluminum, then treated usually with an acid and other chemicals to harden it, and then usually dyed with an aniline dye.<br><br>If you find that the aluminum is not anodized or coated, it could be just really oxidized, which will make it non-conductive. Aluminum is very hungry for oxygen, and bare clean aluminum surfaces will oxidize very rapidly. If you think this is the problem, try sanding the surface so it is bright shiny aluminum and try your etch on that.<br><br>Good luck! Please post here and let us know what happens.<br>
<p>OK, I tried again last night, and kind of got an etch. Not very deep at all. I think I have to increase either the salt in the solution, or the power it's getting, or both. Any ideas?</p>
<p>No, I'm afraid I don't. I have never had issues with aluminum.</p><p>Try upping both salt concentration and power and see if it helps.</p><p>You can of course just run it longer, but you run the risk of the metal getting eaten out from under the mask (this is called &quot;undercutting&quot; when you are etching with electricity or chemicals).</p>
I had scrubbed the heck out of that piece before I tried. Today, I bought a roll of aluminum flashing from Lowe's and cut a piece of that. I sanded it, then scrubbed it with Dawn to get rid of any oils. I'm now applying the resist (P&amp;P Blue), and I'm going to give it another try tonight. I'll let you know how it turns out.<br><br>Thanks so much for your reply and help!<br><br>Connie Carufel
Are you sure the + goes on the piece to be etched? I had it hooked up to a car battery for about an hour and got only a few bubbles from the stainless on the -. When i reversed the wires the knife i was etching started bubbling quite rapidly.
<br>Hi Cameron G17...<br><br>Yes, I'm &quot;positive&quot; about that' ;)<br><br>Actually, I did a demo one time and hooked it up backwards, and all the stencil elements that I had carefully cut out of vinyl sheet instantly popped off and floated into the salt water when I connected the power.<br><br>I'm not sure what the problem is with your setup. Does the battery have sufficient charge (check the volts, should be close to 14v)?<br><br>Also, check the polarity with your digital multimeter to be sure the car battery isn't charged backwards or the wire colors are switched or something weird like that.<br><br>Maybe try a different piece of metal for the sacrificial metal.<br><br>Let me know what happens...thanks!<br>
<p>Hi Jim,</p><p>Great tutorial! Wealth of information here. How deep do you think it is safe to etch Aluminum? I'm trying to etch my project as deep as I can but I want to avoid &quot;undercutting,&quot; as you say. How long would you recommend keeping it in the etch bath?</p><p>Thanks,</p><p>Daniel</p>
<p>Sure, aluminum was the first kind of metal I ever electro etched and it worked great. </p><p>I guess any metal except mercury or gallium would be OK. Maybe not uranium or plutonium or sodium or lithium either. Probably others to avoid along those lines. ;)</p><p> But anything you can buy at your local hardware store or metal yard will be fine.</p>
<p>Hi Jim-</p><p>Second question. I'm very unclear on what power supply to get. I've heard that battery chargers work well, but I just don't know which one to get, the market is so saturated. I found this plug-in unit on ebay: <a href="http://www.ebay.com/itm/Black-Decker-BM3B-6V-and-12V-Battery-Charger-Maintainer-1-5-Amp-/252380838279?hash=item3ac311f987:g:cb4AAOSwn9lXLMvj&item=252380838279&vxp=mtr" rel="nofollow">http://www.ebay.com/itm/Black-Decker-BM3B-6V-and-1...</a></p><p>Do you think this would work? If not, what should I be looking for?</p><p>Thanks again,</p><p>Daniel<br></p>
<br>Hi Daniel...<br><br>I would not expect any digital battery charger to work for etching. In my experience, they are TOO smart and they know it isn't a battery that is connected to its terminals.<br><br>You could use a standard power supply. Search eBay for &quot;12 Volt 5 Amp (12V 5A) DC AC Adapter Charger Power Supply&quot; and you'll see what I am referring to.<br><br>Good luck!<br>
<p>Thank you! That helps.</p><p>I looked up what you suggested on eBay and I found mostly laptop charger-esque chargers like this one: <a href="http://www.ebay.com/itm/12-Volt-5-Amp-12V-5A-DC-AC-Adapter-Charger-Power-Supply-Cord-LCD-Monitor-/251648430285?hash=item3a976a50cd:g:EUwAAOSwPhdVUxki" rel="nofollow">http://www.ebay.com/itm/12-Volt-5-Amp-12V-5A-DC-AC...</a></p><p>Would this one work? </p><p>Thank you again!</p>
<p>I think that one will probably work fine.</p><p>Good luck!</p>
Hi im giving my friend a hip flask for his birthday, do you think this would be possible to do on a hip flask?
<br>Yes, it would definitely work as long as it is metal and has no coating. You can check the surface with a DMM (digital multi-meter) to make sure it is conductive from one area to another. Sometimes flasks and other metal objects have a thin layer of polyurethane or lacquer on them to keep them from tarnishing.<br><br>That sounds like a very thoughtful gift that your friend will always want to keep!
Let me just add two quick points:<br><br>1.) Don't go too deep. You might want to be able to peel off a spot of tape or vinyl to check the depth as you etch, then dry off the surface really good and reapply fresh tape or vinyl to recover the inspection area. It would suck to etch pin holes into the flask, unless you wanted to do it as a joke gift. ;)<br><br>2.) You can also use other techniques like using Cermark with a laser cutter to apply a black image or design to the flask. If you live near any of our 11 TechShop locations worldwide, then you can use one of those.<br><br>The other technique I was thinking about that would work would be to create the mask just like you're going to with the etching method, but apply a coat of Pebeo Porcelaine glass paint (here's a link to the black Porcelaine on Amazon, but they have all colors: http://amzn.com/B00266L07I) with spray, brush or sponge. Then remove the mask, and bake the flask at 150 degrees C (302 degrees F) to fire the Porcelaine glass paint. I use this paint for all sorts of things, and it is really awesome. You can thin it with isopropyl and spray it with an airbrush. They also have Pebeo Porcelaine paint pens if you want to draw your design onto the flask and then bake it on.<br><br>Good luck!<br>
Thank you for the quick answer and advice!
<p>Trying to do this within the next two days for a friends birthday. I have/can easily get all the supplies, but electricity tends to go over my head. Would a 12 Volt, 5 Amp battery be fine for applying the charge?</p>
<p>Hi, yes that will work fine, just check it every 20 min. you can loose some fine details if you leave it longer with a bit higher voltage. :)</p>
<p>Thank you all so much! I'm going to be trying this with a 12v 9 amp battery, and hope that all works out. </p>
<br>Hi Flamel777...<br><br>Yes, that will work fine while the battery is charged up, but the etching process takes quite a bit of current so the battery might go dead fairly quickly.<br><br>Your 5 amp battery means that it can supply 5 amps for 1 hour, 1 amp for 5 hours, 1/10 of an amp for 50 hours, or any combination along those lines. So depending on how much current your etching set up consumes, you can calculate the time you will be able to etch for.<br><br>Good luck! Your friend will love it, I'm sure!<br>
<p>Thank you so much for responding so fast! I'm going out to buy my battery pretty soon, so I'll look for something with a higher amperage. However, I also have a trickle charger that can put out 12 volts at one amp (forgive my syntax, I only have a rudimentary knowledge of this stuff), would hooking it up while doing the etching increase the life of the battery? It doesn't have any &quot;smart&quot; features, so I would assume so. But if that doesn't work, or is unsafe, or such, could I simply use the battery until it runs out and then charge it up using the trickle charger (which would take forever, I know, but I still have a day and a half), and plug everything back in? I'm only doing a small piece, so I imagine it won't require a ton of charge. Fingers crossed, at least... </p>
<p>Hooking the charger up to the battery should work just fine because it is not a smart charger. You could try etching just from the charger itself.</p>
What other way to attach the lettering and something besides vinyl if you don't have a cutter or that material thanks for your help, Darrel
<p>I do it with liquid masking tape and a tooth pick, it is a kind of liquid latex, after you take it out of the bath, you just peel it with your finger tips. Hope that helps :)</p>
<br>Hi Skimann747...<br><br>You can use any water-resistant material that will seal the surface and keep the salt water (and electrical current) from reaching it.<br><br>Some materials could include electrical tape, scotch tape, nail polish, paint, paint pens, Sharpie pen (maybe), circuit board resist products, and many other things.<br><br>The tricky part is getting the desired artwork established into the resist. If you don't have any CNC computer-driven equipment, then you can use an Xacto knife, needles to scratch, or other implements. You just have to do it by hand.<br><br>You also could possibly use the Toner Transfer method. This is where you print your design on a laser printer (not a laser cutter), and then use heat and pressure to make the toner transfer from the paper onto your metal surface. There are tons of web pages about how to do this, and probably dozens of Instructables too. I used to use this method for making circuit boards, but now I use an OtherMill which is much easier.<br><br>Good luck!<br>
<p>Hi, has anyone tried this with Sterling silver? I think is works the same but i have doubts on what to use as a sacrifice metal, i tried with copper and worked great.</p>
<p>Thank you very much for this tutorial. It is the safest and easiest way to etch that I have seen.!!!!!</p>
<p>Hi, Can we use Laptop charging adapter giving output 20V, 5amps as a etching instrument?</p>
<p>Probably not. Modern laptop AC adapters are &quot;smart&quot; devices, not simple DC power sources. I think it needs to &quot;talk&quot; to the laptop's charging circuit before it supplies substantial amounts of juice.</p>
<p>I love the idea of this and want to make an anniversary gift for my wife. But, my window to do so now is tight. So, a few questions:</p><p>1) If I want to have a silvery metal for this, would steel or aluminum work faster (so I have time for do-overs).</p><p>2) Do I need something as powerful as a car battery. Or any 7 or 8 amp, 12V battery will work?</p><p>3) With all the reservations expressed about stainless steel in the comments, what would be a good substitute for the sacrificial piece?</p><p>Thank you very much for posting this. It looks like a real fun project.</p>
<br>Hey, that's cool that you want to make something for your wife. She will love it (no matter how it turns out)!<br><br>1.) Steel and aluminum will work, but I don't know if they would be faster or not. Aluminum was the first metal I used for electro-etching back when I started TechShop (almost 10 years ago). I made a TechShop logo in a block of aluminum which was etched in backwards so I could hand-emboss the gift certificates we sold to raise some of our initial funding. I used a ball-end burnisher to rub the paper into the engraved area.<br><br>2.) Any DC power supply will work as long as the amperage is high enough. Voltage can vary from maybe 5VDC to 24VDC. If you use a smaller battery, you just have to think about how you will recharge the battery and how often. You might be able to keep the charger connected to the battery during the etching, but it depends on the charger...some don't like to put out power unless they detect a battery and only a battery.<br><br>3.) I personally believe stainless steel is fine for the sacrificial side. You can actually use any metal, but you want to be sure it has a large surface area. You could use something like stainless steel scrubbers.<br><br>Good luck!<br>
I did it but it gave that result? Why?
<p>Hey there! I had the exact same problem. After a lot of research, I did some experimenting and found the source of the problem and the solution. Like you, my first stainless projects were heavily pitted / granular, and took a long time to etch; even though it masked pretty well with vinyl, it had a tendency to bubble up under any paint resist and push the resist off (thus pitting where it wasn't supposed to). If you let it continue to etch, it would develop a rough, granular texture - that while interesting, the texture isn't very pretty. </p><p>The main issue is that stainless requires much more energy to etch, and I (like you I think) had barely enough conduction in the electrolyte to etch; I think what happens is that it creates little pinpoints of connection through the electrolyte instead of a nicely evenly distributed current across the metal. </p><p>The solution is to maximize the conductivity of the electrolyte. I found that if you heated the water, and kept adding salt / stirring until it literally couldn't hold any more salt (saturation). It took a surprising amount of salt! Then I liberally added a bunch of white distilled vinegar (by eye, about 1:8 ratio to water I guess), and then tried adding in more salt. By adding the vinegar, it effectively becomes electrochemical etching I guess. I read somewhere that adding hydrogen peroxide helps too, but I'm not sure how that might help; it won't add significantly to the acidity. The vinegar certainly helps keep the solution clearer than just salt water alone.</p><p>I've attached a before/after picture of two experiments. Both are stainless steel plate, prepared only with abrasive sanding and paint thinner to remove the oil from my fingerprints and vinyl sheet labels for the masks/resists (I did use a paint resist on an earlier attempt that showed the same area-pitting that you have). The first shows the rough pitting (about 6 hours etching), the second is nice and smooth with sharp edges and surprising depth and lack of undercutting (about 1 hour etching). I use an Evercharge 12v/6a battery charger for the juice. Handle and dispose of the used electrolyte responsibly, good luck!</p>
<br>Hi MS...<br><br>That's weird.<br><br>The only thing I can imagine is a problem with the power supply, or your metal has a coating on the whole surface like maybe some sort of varnish.<br><br>Are you using a DC power supply? AC power might cause that sort of thing to happen, but I'm not sure.<br><br>Check your metal surface with a multimeter to be sure that it is conductive across the areas you are trying to etch. If there is a film or varnish, then it will not be conductive on the surface.<br><br>Very strange indeed! Please let us know what you find.<br>
Can you give me an idea of the ratio of salt to the volume of water? I understand the more salt makes the water more electricity conductive but I have no starting point. I tried this salt water solution and I put 1/4 cup of salt in 3 quarts of water. After about an hour and a half in the salt water solution and using a fully charged 12volt motorcycle battery with the positive terminal connected to my brass and the negative terminal connected to a scrap piece of iron, the depth of etch was only about 0.0005&quot; I am actually needing about 0.005&quot;. I have used an acid solution in the past to etch brass and had success but I am looking towards salt water as a safer solution. Thanks for a great tutorial.
btw i think the green tinge is actually due to the chlorine gas produced
You might be right! However, it did not smell anything like chlorine. The green color was just like the color you see on brass and copper when they acquire patina.
<p>You're right, it's the hydroxide reacting with the copper. You'll get a vile shade of brown with iron(III) and a dark green with iron(II).</p>
I made a rustic version of this for my great grandfather's grave.

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Bio: I'm the Founder and Chairman of TechShop.
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