Etching Copper or Brass the Cheap & Easy Way (Updated)

I usually think of metal etching in terms of making printed circuit boards, but this basic technique will work whether you want to push electrons down a chute or just want to etch “TOIL IS STUPID” on a copper bracelet. It’s all rock and roll.

I’ve been doing PCB etching since I was 15 or so. For most of those early years I manually applied the resist mask, either using a Sharpie-like “etch resist pen” from Radio Shack, or a grease pencil, or layout tape, or rub-on decals. Later, the more ‘sophisticated’ photo-etch process was used (note: don’t bother using the spray on emulsion, it has never once worked for me: stick to pre-sensitized boards or look into the photo emulsion films out there) but for quick& dirty prototypes of two layers or less I’ve migrated back to using the “toner transfer” method: laser printing (or photocopying) a design onto the cheapest photo-paper available, then ironing it onto copper clad boards (or brass/copper sheets) with a clothes iron.

It works really well & is cheap and easy (just like me)….

Here’s the method that works for me (photos coming next time I etch something)- but nota bene: this version of the “toner transfer method” is most suitable for fairly shallow etches (20 mils or so) on flat substrates. Of course, it can be augmented with manually applied resists after initial etching if the toner resist gets undercut or starts to ‘let go'(hey, it happens): asphaltum, shellac, lacquer, waxes & etc can all be applied on an as needed basis.

  1. Create your artwork. For PCBs I use EagleCAD. There’s a (limited) free version available at www.cadsoft.de , but use any drawing program you have handy. I’ve made a tweaked parts library to make one-off circuits, with all the pads set to as large a diameter as possible, with the through-holes shrunk to 10 mils: this helps center the drill when “punching” the boards I make myself. For other free-form artwork, just remember that lines finer than 10 mils are going to be tough to transfer and etch reliably.
  2. Print your artwork out mirrored (‘horizontal flip’ or whatever your software calls it, so any text or footprints won’t be backwards) onto cheap glossy photo paper. I’ve had great luck with “Office Depot Multi-Project Photo Paper” which is their low end paper, but it works better than the pricier ones. If you can give the photo-paper a tounge-test, you want the glossy side to feel starchy when wet. If your laser printer supports it try setting it to print on “Transparency” to put out as much toner as possible.
  3. Plug in your iron and crank it up to the highest setting. My iron is just for ironing metal, so it has never seen any water, but if yours has you best be emptying it out beforehand and allow extra time for all the water to cook off as steam will definitely screw up the transfer process. Give even a dry iron a full 10 minutes to get up to temperature, you’ll be glad you did. While the iron heats up you can—
  4. Get your metal very clean and grease free. Start with hot water, scotch-brite and some abrasive cleansing powder, and scrub it like a maniac. Any shellac or varnish left, even oils from your fingers, will screw it up. After scrubbing and rinsing and wiping dry, get some acetone (beauty supply or paint store) on a paper towel and give the metal a good firm wipe-down. Check for residue on your paper towel; if you see grunge there, keep wiping it down with fresh acetone and new paper towels until you get nothing off it. That’s clean enough. Use a blow drier to get it dry now if you feel strongly about it, or just let it dry at its own pace.
  5. You’ll need a hard surface to iron on. I have a chunk of half-inch aluminum plate now, but some thick cardboard or a dry wooden cutting board will work just fine. Place your copper-clad board or sheet of metal on the hard surface and position your laser-printed artwork face down on it. Take the hot iron and press the artwork onto the metal. You’ll want to press fairly hard, but not hard enough to smear the toner image. I’m guesstimating 10-20 pounds of pressure while moving the iron around a bit. By the time you can see the artwork through the photo-paper you’re probably pretty close to done: the metal is hot and the toner is melted to it.
    If you are doing a two sided design or PCB, place a couple of fiducial marks (I use tiny pads with tiny holes) on opposite corners outside the main body of the design. Drill the fiducial holes with a very fine bit, then use pins to align your second-side artwork.
  6. Safely put aside the iron. Take the metal with the photo-paper now firmly adhered to it and drop it into some water. I use the bathroom sink. You want the whole thing submerged and the water to saturate the paper, so leave it there for at least 10 minutes and don’t rush it. Once the water soaks in, the “starchy” emulsion side of the photo-paper will release the toner which is stuck to the metal. As a rule, if I try lifting the paper and it picks up the metal without letting go it isn’t ready yet!
    Don’t rush it, let the water do its job: this has never taken more than 30 minutes for me.
  7. Once the photo-paper has turned loose remain aware that touching the metal will leave oils that can muck stuff up. Don’t sweat it if little bits of photo-paper are still stuck to the metal. The etchant doesn’t care about the paper and will go through it. You want as much paper off as possible, with as much artwork stuck to the metal as possible.
  8. You should probably wear gloves and goggles and personal protective equipment for this and all following steps. Mix two parts of muriatic acid (AKA dilute hydrochloric acid from the hardware store) to one part hydrogen peroxide (from the drug store). This mixture is your etchant, which will work for copper, brass, mild steel (somewhat) but NOT aluminum (which will dissolve rapidly and make a stink). I really can’t stress enough how much nicer this concoction is than the Foul Brown stuff is when it comes to NOT staining the sink or your fingers. While still a “nasty chemical” is is far more benign than many (N-stoff, for example), but you should wear your personal protective gear anyway (could blind you from eye contact, or soften your hands). It is very transparent, making it much easier to monitor the status of your work as it etches. (Some people will add one part water: try it yourself. Me? Instant gratification takes too long).
  9. Pour the etchant into a glass or plastic container big enough for your artwork-enhanced piece of metal. You want enough to cover the metal, and all the uncovered metal will be etched. (I’ve found that vinyl “contact paper” makes an excellent masking for the reverse side of metal sheets and circuit boards).
  10. Plunk the metal into the etchant, watch and wait. You will notice the etchant turning blue-greener as the process goes on (almost immediately from the start, aye). This is the copper chloride building up in the etchant, which will gradually become spent. If you see any breakdown in the masking or artwork you can pull the metal out of the etchant, rinse it off well and apply touch-ups with a Sharpie pen, black tape, nail polish, wax, asphaltum, whatever will block etchant, then plunk the metal back in (this is not rocket science).
  11. When it gets etched enough for your tastes, take out the metal and rinse it off. You can remove the toner with acetone (from the beauty supply house) or just good old scotch-brite/abrasive cleanser/etc.

NOTE: You might want to save your spent etchant for a kinda neat trick (H/T to MAKE Magazine).
A clean tin can (real tin plated steel, that is) placed in the spent etchant will have copper deposited on it in a manner much smoother than what you get out of copper sulphate on ferrous metal.
I haven’t got around to trying to do an electroplate with this spent etchant yet, but I’ve read encouraging hints… and have several quarts to play with. Stay tuned.

Update: If you are going for capital A ‘Art’, and not PCBs or some-such, you’ve got a broader range of options:

  1. Use tape or contact paper (with a hole cut in it where your art will go) to mask off the bulk of the copper or brass piece you want to etch.  (All metal cleaning steps above still apply, prior to masking!).
  2. Fill in the hole in the mask with a good smear of silicone grease (from the home improvement store plumbing aisle) or beeswax, or shortening or lithium grease, etc.
  3. Apply your caligraphy to the grease with a toothpick (or tool of your choice) to expose the metal to the etchant.
  4. Etch the metal as described for PCBs, above.

The best thing about the peroxide-HCL etchant is that’s it’s relatively benign to skin, allowing you to amend your designs as you go, and it’s fairly transparent so you can monitor the goings on in progress. More like cooking than baking that way, eh?

You might also want to check out the more recent entry Parchment PCB Toner Transfer: Updated for a newer twist on toner-transfer etching.

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18 Responses to “Etching Copper or Brass the Cheap & Easy Way (Updated)”

  1. 3wishesstudio Says:

    I can’t wait to give this a try – thanks for the info! A new play toy WOO HOO!

  2. Etchy girl Says:

    This seems to be an amazingly cool idea to work on. I‘ll make sure to work in a well-ventilated space and reuse the etching solution. If you pour your etching solution into a tub with a lid, you can easily store the solution until you need it for your next etch.

    • offlogic Says:

      Thanks! After you exhaust the etching solution you can use it to plate copper onto tin as well. Just clean the tin-plate well with alcohol or acetone and immerse in the spent etchant and you’ll get a fairly bright copper plating right before your eyes. This also renews the etching solution for more copper etching.

  3. offlogic Says:

    I received your query concerning 2mm x 60 x 30 brass etchings.
    If you could tell me how many you’d like, provide specs on resolution, etc, I’d be happy to respond with a quote.

    Thanks for reading!

  4. Combi Boilers · Says:

    well, our bathroom sink is always made from stainless steel because they are long lasting “.-

  5. Dawn M. Miller Says:

    From what I understand, this sort of etch is “never spent.” Keep adding a little hydrogen peroxide, and it will last forever.

    Link:
    http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!–A-better-etc/#step1

  6. joseph Says:

    seems a little slow with this solution.

    it seems like all the other references to this method use a 1:2 ratio of acid to peroxide. is this a typo? do you think this may etch faster?

  7. Christopher Says:

    Dear Offlogic,

    This method is intriguing but I have had no luck whatsoever getting the paper/toner to adhere to a brass plate. I have tried different papers (Staples, since no O.D. nearby), different heat settings (from fairly to very hot), without any adhesion.The brass has been clean.

    Is the toner supposed to “bake” onto the surface? Every time I’ve tried, it remains on the plastic surface of the photo paper. Have you a suggestion? Thank you.

    Christopher

    • offlogic Says:

      Getting a good toner transfer is the hardest part, yes. I can generally nail it in three tries or less after much practice (that makes it “artisanal”, right?).
      Are you getting complete failure to bond (whole sheet just not sticking) or spotty transfer? Usually by the time I have ironed at the hottest setting on the iron long enough to see the disgn on the back of the paper it’s pretty well done.
      A couple of things to check: The type of photo paper matters a lot. Inkjet paper with starchy printing surface feel (the “tongue test”).
      Might have to experiment to find the best one, and the cheaper grade seemed to work better for me than the high-gloss fancy one (the plasticy ones WILL NOT WORK AT ALL).
      Some people have been able to substitute laser-jet transparency sheets or the backing from peel and stick sheets (I won’t run that through my laser printer, skeered of adhesive residue) or glossy magazine paper, but I got good results with the right “multi-purpose” inkjet photo paper.
      Sometime the cleanest brass sheets just won’t stick, even after soaking in straight acetone. For those hard cases a quick wipe with the HCL-H2O2 etchant usually gave them enough “grain” or “tooth” for the toner to hold on to.
      Let me know if I can help get this working for you, it’s a hoot when it does. Right paper, clean brass, hot iron, high pressure seem to be the key points.

  8. Dean Says:

    I photocopied my design onto xp photo paper. Darkest setting. I was etching onto aluminum (no stink at all btw). Used 4:1 (peroxide:muriatic). I prepped my metal by cleaning, then using fine sandpaper-wipe and clean after sanding. hottest setting on iron. folded paper towel over a ceramic tile. placed my metal with design on that, saturated the photo paper with 70% isopropyl, laid another folded paper towel over that (sprayed with isopropyl) then hot iron. maintain pressure overtop. 5-10 minutes…absolutely perfect and complete transfer. I did this for fine lines/details (less than 1mm) and as long as my etchant solution wasnt too acidic (even try 5:1) to avoid too much of an exothermic reaction, the result was really god detail.

  9. Elliot Says:

    Does this require a laser printer or will an inkjet work too? Having trouble getting the transfer to bake onto the metal, like Christopher.

    • offlogic Says:

      Elliot-
      You MUST use a laser printer or xerox photocopier type printout for the transfer, the kind that has “toner” rather than ink. Toner particles are plastic, that’s what resists the etchant/mordant.
      Are you working with copper-clad PCB material or something heavier? It might be that a heavier piece of copper just takes a lot more heat to get it up to toner-fusing temp. Might try pre-heating it with a heat gun or in the oven.
      I recently came across this project (http://www.instructables.com/id/Toner-transfer-no-soak-high-quality-double-sided/) that uses baking parchment in place of photo paper and adds Brasso metal polish and a tarnish remover to the metal prep. I haven’t tried it yet myself, but the upshot is “clean the hell out of that copper”. I get consistent results with Comet cleanser but I’m always looking for improvement, and have never got a good transfer without ultra-clean copper. Tried a wipe-down with straight acetone? A very light pre-wash with etchant/water rinse?

  10. Robert P Guthrie Says:

    This is some of the best and understandable info I’ve come across. Thank you. I’m gona give this a try and if it works out Ill stat up a business making MMA title belts. If you have any more hints tips or tricks contact me at the web address I left. THANKS

  11. pookieP Says:

    I have about a couple dozen old sheets of copper of 10′ length and varying width — 4″ – 18″. I had fun just reading your directions. Thanks much. After we get moved, and i have my left hip replaced, and i argue for an independent work area, then i will get with it. The rest of you have fun too. Thanks again. pookieP — cheers101@sbcglobal.net

  12. Fabian Says:

    Infformative article, just what I needed.

  13. John from Australia Says:

    If you look around you can get new laser printers cheap from office supply stores. I purchased 2 new Xerox Laser printers 6 month ago for $29 each. That’s cheaper than the toner cartridge alone. I use your method for setting up the circuit boards and it works well.
    I always use inkjet photo paper in the laser and works the best as the toner sticks to the inkjet paper but releases easy when heated off.
    One question – how long would your etching mix take approximately on brass sheet? I need to do some N scale (1:160) etchings?

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