Custom boards at home without etching

PCB

PC board houses are getting more accessable and less expensive all the time. Some of us are even getting very, very good at making our own circuit boards at home. There are times, though, when a project or prototype requires an extremely cheap custom board right now, something etching a custom board won’t allow. [KopfKopfKopfAffe] has a unique solution to this problem, able to create custom boards in under an hour without any nasty chemicals.

Instead of starting his build with copper-clad board, [KopfAffe] used every rapid prototyper’s friend, simple one-sided perf board. The shape of the board was milled out on a CNC machine, and both the top silk screen and bottom layer were marked off using the toner transfer method. After that, a custom circuit is just a matter of placing components and putting solder bridges between all the marked pads.

[KopfAffe] is only using this technique for single-sided boards, but we don’t see any reason why it couldn’t be employed for simple double-sided boards. This would still have the problem of making vias between the layers, but that’s still a problem with proper, home-etched double sided boards.

39 thoughts on “Custom boards at home without etching

    1. True, but why not just use a piece of solid hookup wire? The individual wires removed from ethernet cable work well.

      Strip the end, push it through. Bend it flat against the board on one side so it stays in place. Flip it over, solder it, flip it back, cut it and solder again. (It takes a lot less to do than to describe). Keep cutting and using the leftover for the next via, a few inches of wire will make many many vias!

    1. (If you get the two-sided version of protoboard, at least, which would be required for this to work with two sided circuits anyway)

  1. u use pref boards 99% of the time and i do somthing similar
    but if you have a CNC why not just mill out a copper clad board?!

    1. well i mostly just do point to point soldering (making traces by connecting solder joint to joint) i dont thiink he gets in to what he does for that ….

    2. I thought exactly the same. If you use the voronoi-method (https://metalab.at/wiki/PCB_CNC) you’ll have a finished double sided board within an hour! [bkubicek] has written some pretty usefull scripts. It needs some practice (at least for me, as this was the first thing to do with a CNC machine), but which method doesn’t?

    3. Because copper doesn’t mill well. Sure people do it, but that doesn’t mean it is a smart thing to do. I suppose if you have the right machine it isn’t too bad, but most folks don’t have that. Not that it slows them down any.

  2. I wonder if you could use a stencil to brush carbon fiber conductive liquid and let it dry as your traces. Then clamp in those little through hole copper sleeves to solder the components to or to as act as a connector for traces on opposite sides of the board.

    1. what i would want to try is paint everything you dont trace with something solder repellent than dip the whole thing in a solder pool
      tho it would be much easier on perf bords with square pads

    1. No.

      I’ve done toner transfer boards the more usual way on copper clad FR4, and you can leave the toner on there and still solder fine. Makes it look like you’ve used a black solder mask, which I think looks pretty cool.

      Does leave some black toner on your solder tip, and is probably not good to breathe though…

  3. Am I the only one that finds bridging a row of pads on perfboard to be like playing Whack-A-Mole? I try to bridge a pad onto the end of a chain, and inevitably one of the existing bridges gets undone—the solder gets sucked toward the iron. Is there a tutorial/video on the “right” way to do this?

    1. Right way: Tin a piece of copper wire and solder it to the pads. Trying to solderbridge them will just result in a big mess. Pretty expensive too considering the amount of solder you go through to get complete bridging all across.

        1. “Because solder is more expensive than copper wire? Maybe if you’re using silver solder…”

          Clearly. Elementary school math and critical thinking skills are your friends.

          Whether it’s worth your time to deal with the wire is another matter.

        2. Why not use the component leads that get clipped off and thrown away? That would kind of make this technique a more structured point-to-point.

      1. What sven said except don’t use copper wire if it’s too expensive. I just use plain ol’ bare hookup wire. It’s just as conductive as the leads on all the parts.

    2. The trick is to let the solder cool as much as possible, and work quickly. First make a row of single blobs. Then go back, and connect them into pairs, then go back and make quads, etc. If the solder gets too warm, go work on something else first.

    3. Perhaps most rapid prototyping using CNC would be possible if you had a protoboard with islands fully connected (bridged) to all their neighbours with thin traces, when in pristine state – the mill would just need cut a finite set of bridges instead of grinding away full lengths of isolation trenches, and as a bonus you would have mesh polygons and planes easily done. Perhaps even without using a CNC mill, cutting bridges with sharp knife would yield results fast.

      1. Before nearly every worthwhile components shop closed their doors, finding cheap boards in that configuration or even vero boards is a bear. No one seems to like carrying that kind of board. Everyone, including Radio Shack last I checked, carried the board described above. It’s really kind of annoying. If a shop does carry decent blanks, they charge a premium. I found it was just cheaper to order a bunch of copper clad scrap board and etch them myself.

    4. Yeah, I don’t get why people bother with dragging solder bridges. I just use the components own leads.

      Keep the first component’s lead uncut, route it along the line you need to ‘bridge’. If it’s long and doesn’t want to stay in place while I attach the rest of the components then I will bend it at the end and stick it back up through another hole.

      Some might say it is harder to make changes. If you have to change out that first component you would have to unsolder all the others. That isn’t really true though. I just cut the lead and leave it.

  4. I sometimes build boards like this, but instead of just using solder bridges, use copper tape. You can get it in a pitch that just covers a row of holes… then you solder to that.

  5. A very interesting idea. From my perspective, though, if artwork for a pcb layout has to be generated (or copied from existing art) and then applied using the toner-transfer process, the only step missing from making a regular board is the etching. For me, that takes all of five minutes (including safe disposal) and uses about 25 cents of chemical. But isn’t etching a big hassle? Not after you’ve done it once or twice. After that, it’s no more of a hassle than frying an egg, except I don’t etch in the kitchen.

    I do like the idea, though, of using toner-transfer to apply the “silk screen” legend.

    1. It’s not as much the etching that’s the problem, it’s getting the vias done that’s the problem. But if you don’t need vias/jumpers, agreed.

      1. Vias are no problem unless you have too many.

        make sure to place the vias well clear of any component bodies (at least 0.5mm away), mount all components, then you thread a piece of solid copper wire through all via holes, solder on both sides and cut away all the excess loops of wire. Done.

  6. “create custom boards in under an hour (…) shape of the board was milled out (…) both the top silk screen and bottom layer were marked off using the toner transfer method (…) placing components and putting solder bridges between all the marked pads”

    In under an hour, really? I suppose this assumes all setup already done (CNC fixtures set, CNC program done and loaded, toner masks created and printed, components collected and ready, etc). If you exclude all prep/setup time, you can probably build a car in under an hour.

    By the way, these should be called Pac-Man PCBs.

  7. carbon black (ie soot) is perfectly good as a resist even for brazing (high temp soldering). Given that it’s err… black, I’m pretty sure it would laser etch pretty well- exposing nice bright copper underneath. Got a feeling that spraying some zinc primer would then coat the board with a reasonably conductive layer -zinc primer needs to be electrically conductive to offer any kind of sacrificial protection. If rubbed gently the zinc should flake off only where it’s been sprayed on top of the carbon black.
    The zinc shouldn’t melt until 419 °C so should be safe from zinc fume fever with a thermo controlled soldering iron. Not sure if it would alloy with solder though.

  8. Hmm. Might it be better to apply a *negative* image to the bottom, with no toner where you’re meant to solder? Even though it’s apparently possible to solder through toner, I’d expect it still slows the process down.

    1. But what of two adjacent holes and tracks that are not connected to each other at any point? It is harder to tell them apart. There must be a thin line between the tracks to split them, so a regular PCB image won’t do without some further pocessing.

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