Electrochemically plated vias for homemade PCBs

By electrochemically plating vias, Bearmos takes home-etched PCBs to the next level. His constant current source, with we covered earlier, is used in the process.

I just finished writing up some of the details on DIY plated through holes. This is what the simple constant current source was designed for. This process was slightly adapted from Think and Tinker – a really great site for DIY PCB fab. The overall process is:
1. Drill holes in the PCB
2. Coat the holes with a mixture of water-proof ink and finely powdered graphite
3. Cure the ink so it doesn’t rub off
4. Dunk the PCB in the electroplating tank, apply current, and let chemistry do the rest of the work.

Via the forum.

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  1. Cool! Gives me something to so with that gallon jug of copper sulfate powder left from my Honors Project last millennia! I modeled dendritic crystal growth and then actually grew dendritic copper crystals, and then compared their fractal dimensions… wild stuff for a comp science degree…all I’d done with it since was some steampunkish electroplating…

  2. we’ve been doing this for a while, and it can be troublesome, especially if you’re milling pcb’s

    one side of the board will get more copper than the other and end up rougher, its really hard to get the mix right .. the secret ingredients being laxatives.

    reverse pulse plating is where we want to go next that should solve all our current problems with this method.

    1. hey there! The last project I saw on your blog you were using mechanical rivits (maybe that was just an experiment with the Bus Pirate). I’m envious of your mill :-) I’m currently running a home-brew mantis 9 derivative with a dremel – complete crap compared to an Accurate CNC.

      The solution in the post is currently using PEG 3500 (I’m assuming this is similar to the main ingredient in the laxitives you’re referring to). Flipping the PCB half way through seems to help even out plating a bit. I’d like to look into brighteners a bit more (the PEG is only a levler) to get a better surface finish and be able to run higher plating currents – reducing the total plating time. I’ve also read about reversing polarity, but haven’t ventured down that road yet.

      The biggest problem I found intially was fringing on the edges of the board. Copper tended to build up along the edges, which raised the PCB unevenly from the milling table, causing varyng depths of cut when running a 60 deg V bit. I’m hoping simply knocking off this uneven edge will help, but am still experimenting.

      There is a forum thread started on this already if you want to throw any more ideas around;-)

      1. We use both, since the rivets only go down to 31mil and some of the boards just need smaller via’s.

        The PEG 3500 – 4000 is indeed the laxatives, and we flip the PCB as well, but no matter what we’ve tried the results get spotty.

        We used commercial PCB brighter and tried just about everything possible.

        I really think the RP is the way to go though!

        see you in the forums :)

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