• MegaDeKay 5 hours ago

    Or just scrub the board with a bit of ferric chloride and a sponge. I've also seen a modified version of this method that might be better for larger boards that puts the board and the sponge in a ziploc bag with some etchant poured in. Use two sponges for a double sided board.

    https://hackaday.com/2009/07/13/etch-pcbs-with-ferric-chlori...

    • squarefoot 4 hours ago

      > Or just scrub the board with a bit of ferric chloride and a sponge.

      If you use ink pen and transfer pads like I did decades ago, the sponge would almost certainly wipe the pads off. The best way that I'm aware of to ensure the copper is being consistently covered by the solution is to use an air pump to produce bubbles under it. Those used in aquariums are quite cheap and durable.

      • wrs 3 hours ago

        Yes! The sponge technique takes a little practice to get consistent results, but it works well (at least for small boards), and lets you use microscopic amounts of etchant, which is good for cleanup. I find it’s especially good when trying to do relatively small traces, because you get such fine control over the process. (I have to say though, nowadays I’d usually rather wait six days for JLCPCB to do it for me.)

      • buildsjets 3 hours ago

        Am I the only one who finds it immensely sad that they are using a microcontroller, code, and a servomotor to replicate the motion of one of the simplest and most basic of machines to construct, a crank and kingpin?

        This is a project for Lego, not Arduino.

        • topspin 2 hours ago

          My design would have a pivoting arm holding the PCB in the fluid and bump or rotate the arm with a cam. Why put the big container full of caustic liquid in motion when you can just move the PCB?

          I've been nerd sniped thinking about this. Latest thinking: simple sliding bar clamp to hold two edges of the PCB. The PCB hangs down into the solvent tank. The bar on the clamp drops into vees at both ends. One end of the bar is bumped with a motorized cam, the other has a spring. The clamp+PCB oscillates back and forth and the arms agitate the fluid. When the cycle is complete you just lift the clamp+PCB out of the tank. The tank doesn't move. Tank shape can be optimized to minimize working fluid and agitation.

          • pstrateman 2 hours ago

            The YouTube video acknowledges the over engineering in the title.

            • dmb2 2 hours ago

              No, I came to the comments after having this exact reaction.

            • Animats 2 hours ago

              The usual way to agitate PCB etching today is to put an aquarium bubbler at the bottom of the tank.[1] Cheap, compact, simple, and you need less etching solution.

              [1] https://www.circuitspecialists.com/et20

              • dvh 2 hours ago

                Piece of string and this bash script:

                   while true; do
                      eject
                      eject -t
                   done
                • daghamm an hour ago

                  I built a similar device some years ago only to realise that all my servomotors where cheap knockoffs that broke after 5 minutes l.

                  Has anyone managed to get those $2 servos on Ali to work reliably?

                  • Workaccount2 4 hours ago

                    I have made a number of PCB's at home. By far the best etchant is warm hydrochloric acid (30%) and peroxide (3%). In a 1:2 mixture (HCL:Peroxide). Will etch a board in about 3 minutes. But be sure to do it outside.

                    • amelius 2 hours ago

                      I don't understand. Ordering PCBs online is nowadays almost as fast as ordering the components. Why would you want to make them yourself?

                      • brotchie an hour ago

                        My thoughts exactly. It's fun as a hobby I guess, but sitting down and soldering a non-trivial board sounds like a PITA vs paying $50 for a respin of 5x boards with full pick-and-place assembly, delivered in <5 days.

                        • bobmcnamara 2 hours ago

                          There are reasons.

                          Mine: phased Vivaldi antenna arrays. Iteration is painful if you have shipping in your run debug loop.

                          • amelius 5 minutes ago

                            Ok, but that usecase is very exceptional.

                          • daghamm an hour ago

                            €40 to receive it in 3 days or €0 to have it in 3 hours.

                          • ein0p an hour ago

                            Just buy them in China. Super cheap even in small quantity and very high quality. Shipping isn’t too bad either. Beats the heck out of figuring out how to dispose of ferric chloride. They’ll even populate the boards for you for a reasonable fee if your design uses SMD parts

                            • pavl 13 minutes ago

                              Can you recommend a Website/service?

                            • StayTrue 5 hours ago

                              I don’t think this is the best way to clean PCBs but it would make a great machine for marinating food, moving the marinade around continuously for max/even absorption.

                              • MegaDeKay an hour ago

                                It would make a poor machine for marinating food. Most of the foods you'd marinate should be refrigerated during the process. A much better way to marinate is throw everything into a ziploc with as much air removed as you can to maximize contact. Flop it around every now and then if you like.

                                • _Microft 4 hours ago

                                  This is not a cleaning process (in the sense of "removing dirt"). One way to create PCBs is to use a board with a copper surface, put a protective mask on the locations that should have traces or pads and then etch away copper from everwhere (else). In the end, only copper under the protective mask will remain. Etching is faster when the solution is moved around during the process. This machine does exactly that.