Etching Your Own Boards Really, Really Fast

Sometimes the planets align and the Hackaday tip line gets two posts that are begging to be used together. Here’s two hacks to etch your own boards at home in just a few minutes.

Toner transfer PCBs on the quick

One way of putting an etch mask on a PCB is with the toner transfer method: print your circuit on a piece of inkjet photo paper using a laser printer, lay that circuit face down on a sheet of copper, and go at it with a clothes iron. This takes a heck of a lot of time and effort, but [Dustin] found another way. He used parchment paper instead of inkjet photo paper. Once the paper was on the board, he rolled it through a laminator. The results are awesome. It’s a very fast process as well – you don’t need to soak your board in water to get the photo paper off.

Etching that’s like wiping the copper away

[Royce] wrote in from the Milwaukee Makerspace to tell us about [Tom]’s etching process that is like wiping the copper off the board.  He used Muratic (Hydrochloric) acid and Hydrogen Peroxide with a sponge to wipe that copper away. The trick in this, we think, comes from the 30% H202 [Tom] picked up at a chemical supply company, but we’re pretty sure similar strengths can be purchased from beauty supply stores. Check out the video after the break to see [Tom] etch a 1 oz. board in just a few seconds.


43 thoughts on “Etching Your Own Boards Really, Really Fast

    1. Have you tried printing on thin glossy paper, prepping the boards with ammonium hydroxide and using a laminator? It’s really very easy and you can make perfect double sided boards with very detailed thin traces really really fast.

      This is from my latest project:

      Traces winding between SOIC pads are nothing to write home about. And it’s double sided.

      1. Nice work. I have been unable to get traces thin enough for soic without severe pitting. My process seems to differ from yours in that I use thick, glossy, photo paper, no ammonia prep, and an iron for transfer.

      2. It’s some random glossy coloured paper bought in a kids section of a local supermarket. It’s white on one side, coloured on another. Pretty thin, thinner than regular office paper, but not too thin so the printer handles it well. It has a Barbie picture on the package. Not sure if this description really helps :) I believe that the key ingredient is the laminator though, because it applies temperature and pressure evenly. Before getting one, I used to have pretty good results with photoresist/UV, but the effort for every board was huge compared to this method.

      3. Canon LBP2900 or something like that. It was the cheapest on the shelf at the time. Really can’t recommend it because they explicitly remove it from their universal CAPT driver on Mac and you really have to spend some quality time with it before it can print for the first time. Shouldn’t be a problem on Windows though. With rare exceptions I only print boards so I’m running like 3rd year on the original refill.

      4. Yes the last time I use glossy paper into my laser printer, it end up costing me a heating unit.

        The paper melt and wrapped around the cylinder.
        I was able to take it out, but I damaged the silicone rubber, giving bad print then…

        But hey, I have the perfect part to build a laminator now!

  1. I dunno, I think I can sacrifice a couple of extra minutes to avoid getting crazy over etching. I can’t imagine using stuff that strong on small traces and thin boards would be a good idea.

    Also, maybe stand under a kitchen fan or something the next time?

      1. Highly doubt that, since undercutting is a factor of time and acid concentration. Weaker acids take longer to undercut because they are weak. Stronger acid ________ (fill in the blank)

  2. Nice demo. I do this with agitation only because I’m concerned the wiping will scratch off the paint.

    A few points. It may be fun and require less patience, but mixing these chemicals together in high concentrations is dangerous. Add a reducing agent like copper, and the mixture will become very hot and produce corrosive fumes. It could easily melt through that plastic container and go on to attack anything or anyone below. Always, always have lots of water nearby. Also, the fumes are corrosive to iron, copper, nickel, and aluminum. Do that too often in an unventilated room, and people will start to wonder why their tools and computer are looking so crappy. Long before that, though, they will suffer painfully irritated eyes, nose, and throat.

    Mix water with the peroxide, etch under a fume hood. WEAR. EYE. PROTECTION. Have lots of water available, preferably an eye wash station.

    And, for Pete’s sake, don’t pour aggressive acids while sitting down, then play around with it on the table. He’s just begging to get a lapful

    1. It’ll mess up your laser printer bigtime.

      The printer uses heat to bind the toner to the paper. Thing is, the toner melts at a higher temperature than the wax in your waxed paper, so the the wax from the paper *and* the toner will end up getting smeared all over the guts of your printer.

      .. and yes, I learned that the hard way. Sometimes your purpose in life is just to be a warning to others. ;-)

      1. This is exactly what I was fearing when I saw that people were using parchment paper. Thanks for the confirmation. Maybe people are cleaning it with normal paper after? I don’t see how this can’t get somewhat messy.

  3. I know that H2O2 + HCl etching is very popular among a few reckless hackers. Nonetheless, I don’t recommend it, if you cannot keep all involved chemicals and tools outside your house. The muriatic acid gives of trace ammounts of HCl even through the tightest cap. This HCl will detroy all metal tools and things round a 2 meter radius of the bottle, or worse. All nonmetallic substances will become polluted with a white haze from NH4Cl, which forms spontaneously from the ammonium in the air.
    Just use a cuvette full of Sodium Peroxide, an aquarium heater and an aquarium pump to pump some bubbles through. It is a million times less toxic, nasty and hassle.

    1. Heed Steve’s warning! This is exactly what happened with my first bottle of Muriatic acid before I knew better. Stored on the same metal utility shelf were many metal cans of various solvents, which got eaten through and leaked all over; in turn dissolving even MORE plastic bottles of chemicals before I discovered it. It was the nastiest, scariest mess I’ve ever had to clean up.

      Muriatic acid is usually 31.45%, at which concentration it fumes strongly and visibly. Diluted by half with distilled water (or sold at that concentration as “Safer” Muriatic), it fumes very little. I still continue to use it, but now only at the lower concentration for safer storage. A bottle that’s been stored a year has a light dusting around the cap of what I now know is NH4Cl (thanks Steve). It doesn’t seem to have affected other, expendable plastic and metal items I placed near it for monitoring purposes; but I’d still suggest some caution.

      Of course, the lower concentration does slow etching time, but the results are perfectly acceptable; and can be sped up with agitation or sponge methods.

      As for 30% peroxide? That scares me even more than full strength Muriatic acid. It’s a really cool demo, but I’d never do it.

  4. my issue is usually that step where he says “break out a sharpie and a scratcher and start corrections” tough my pen plotter can only go down to 25 thou, it never needs mask corrections. but I shall try this, I also need to start up a batch of that renewable etchant…

    1. I rarely have to make Sharpie and “scratcher” corrections if I am careful with the paper and the laminator. All the traces that break have done so because I rubbed them with my finger while taping the paper down. My last few boards were electrically perfect. If I could just find a good way to do the damn through holes…

  5. I have a xerox phaser 8600 that uses solid state (read wax) ink and i was thinking of printing straight onto flexible copper sheets and etching from there (also making ribbon cables).

    has anyone tried this? any places for decent price copper sheets that could go through the printer without damage?

  6. I have an issue with the muratic and peroxide mix. It works great immediately after mixing and etching the first board. Turns green as it should and all but then doesn’t work after it sits for a day or more. I add peroxide to reoxygenate and it doesn’t help. It turns the copper that peach color but then does nothing else. Any ideas?

    1. Cupric chloride (CuCl2) works by oxidizing metallic copper to cuprous chloride (CuCl):

      CuCl2 + Cu => 2 CuCl

      Exposing cuprous chloride to oxygen will make the copper give up an electron, which allows it to bind another chlorine ion, taking the CuCl back up to CuCl2.

      Thing is, that reaction consumes two more chlorine ions. It also consumes hydrogen, because the oxygen with the new electron will want to bind to a couple of hydrogen atoms to make water.

      So your solution will lose hydrogen and chlorine as you use it.

      The last piece of the puzzle is that CuCl is only weakly soluble in plain water, but highly soluble in a solution with chlorine ions. When your etchant gets depleted, you’ll get a white haze on the surface of the copper (CuCl in its solid state) that prevents any further etching from happening.

      If you went light on the acid to start with, your etchant may be starved for HCl.

  7. I’m sure it wears a number of different hats, but it might be of interest to know that this is the metal-etching step of the classic ‘RCA clean’ used extensively in silicon processing.

    Also it’s nasty, so take care!

  8. That’s insane, it’s an incredibly quick etch but surely you could just as easily mix it a lot weaker and take your time, the point of the sponge method is to get the etch done as quickly as possible with whatever strength of etchant you are using. That mix doesn’t look like it needs a sponge, just a liberal agitation method. The etch process is so quick that they are getting undercutting, not really what you’re looking for in a ‘good etch’. It seems they’re working too fast for their own good, make the mix weaker, gain better control over the etch process, give yourself time to react!!

    So in reality it seems that you should really get your etchant mix to work at a safe level that isn’t going to give off acid rain, won’t burn through plastic or you :D

  9. This etching mixture is quite nice, but…
    It’s too corosive for narrow traces (while getting hot, and it IS getting hot).
    Remember to NEVER EVER mix it with acetone (used to wipe out toner/paint off traces). It forms acetone peroxide, and you can find a hole in your floor one day, in place where a container with wasted chemicals used to be.
    Sodium persulfate is nicer, at least for me :)

  10. The best transferring medium is the shiny back paper of the self-adhesive label sheets. Just buy a sheet of label paper, throw away the label and print your circuit on the shiny silicon-coated side of the back paper, then simply iron it on the PCB. Then let it gets completely cold then remove the paper from the board. You won’t believe how faster, easier and more accurate is this method than other methods specially this and the glossy paper method. I made really complicated and superfine 2-sided PCBs using this method with ease.

  11. I usually don’t mind taking reasonable risks to get cool stuff done, but this is ridiculously dangerous to do indoors for several reasons:

    The extra oxygen in hydrogen peroxide reacts exothermically with the H+ ions in solution, leaving excess Cl- ions that build up and get released as a gas (the bubbles). Even a small volume of concentrated hydrochloric acid contains enough chlorine to produce a large volume of chlorine gas.

    The bursting bubbles will spray droplets and create a mist of hydrochloric acid that can be breathed in along with the chlorine gas.

    The heat produced by the reaction is enough to soften up plastic bottles, so if you really must try this, do it in something (e.g., glass) that will withstand the temperature.

    That said, I have done this myself and currently use the cupric chloride produced to etch my boards. To do so safely, I simply make sure that there is always an excess of copper ions (e.g., from the board being etched), not chloride ions, to go around. That keeps chlorine from escaping as a gas even when I refresh my etchant with a few drops of hydrogen peroxide.

    But again, if anyone wants to try this, DO IT OUTSIDE, with full-length sleeves and goggles, and even then keep your face away from the solution!

  12. If you’re paying good money for etchant, don’t etch huge chunks of copper away that could easily be left as a ground plane, and similarly, if things aren’t tight make the tracks fatter. Why etch what you don’t have to?

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