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The plastic I would like to use is Polycarbonate, which will melt if you try to solder metal to it. If you can't weld the two, is there another way in which you can join metal to plastic? Ideally, I would like to build the circuit board into the polycarbonate itself.

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    \$\begingroup\$ Have you tried conductive adhesive yet? \$\endgroup\$ Apr 22 '14 at 19:35
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    \$\begingroup\$ You will never 'solder' metal to plastic! \$\endgroup\$
    – Cornelius
    Apr 22 '14 at 19:36
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    \$\begingroup\$ What do you mean by "build the circuit in the poly"? You mean like encasing the PCB? or dipping the pcb in the poly? or you are hoping to etch the tracks on the poly, i.e. you'd like a pcb that has polycarbonate instead of FR4 or whatever? \$\endgroup\$ Apr 22 '14 at 19:42
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    \$\begingroup\$ @VladimirCravero, I'm looking to build the circuits into the Polycarbonate. I'm looking to etch copper tracks into the Polycarbonate. I'm working with a very limited amount of space, so ideally, instead of using a board, the tracks and components will be built into the polycarbonate. \$\endgroup\$ Apr 22 '14 at 19:47
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    \$\begingroup\$ @MichaelPicard I see, but I don't get how poly can save space versus FR4 \$\endgroup\$ Apr 22 '14 at 20:04
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You should consider building your circuit on a thin (flexible) polyimide substrate, and then either gluing or heat-staking that circuit to your polycarbonate case.

Flex circuits are as easy to design as regular rigid PCBs (although there are a few more design rules), and there are many manufacturers that can produce them for you.

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  • \$\begingroup\$ Alternately, gluing (I've had good luck with epoxy on polycarbonate) copper substrate to the polycarbonate substrate and then using normal etchant to make the PCB. I don't know how etchants react to polycarbonate, though. Soldering to the final product will be... interesting. \$\endgroup\$
    – lyndon
    Apr 22 '14 at 20:16
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Two options. One easier to reproduce than the other.

The first is inlaying, which comes in two forms of application. First you mill or cut out a channel. You can use a standard bit or an inlay or keyhole type bit to privde better grasp. Then you can 1, cold form a conductor into the channel (read: hammer it in) or 2, hot form it (pour molten metal). Heck, get a lot of low temp solder (lower than the burning/melting point of your plastic, and a heat gun.

The other is copper tape. You just cut and tape it to the plastic. If you want to get fancy, you use copper sheets in a mill/plotter. You can get them with glue umm, glued on, or without, and use your own spray adhesive.

Either can be done by hand or machine.

Depending on your needs, conductive glue or ink might work as well. It really depends on how complex your circuit is. Invest in some kapton tape (high heat resistance) to protect the plastic while soldering on it, use the least wattage iron needed, and practice your ninja soldering.

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  • \$\begingroup\$ Would you mind emailing me? Mpicardd at gmail.com. It would be great to talk to you further about the product. I'd love to bring you in on the project if you're interested. \$\endgroup\$ Apr 23 '14 at 1:24
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I know this topic is 5 years old now but I want to share something. My keyboard was spilled some juice and CTRL and Caps Lock keys were not working. I tried to fix it but some traces on the plastic shield was burnt therefore blocking the electronic contact between the main PCB and the keys.

What I did think to do was creating a bridge over burnt traces to get the contact back. I tried directly soldering it but since plastic doesn't really matches with solder, it didn't catch it and I wasted some of solder during that process. I even tried silicon but it didn't work as expected.

So while I was searching something useful in my tool box, I saw staplers and that crazy idea popped in my head! I can use this stapler pins to create electronic contact so I can solder the cable which I'm going to use it for the bridge directly to the stapler pin! I stapled one across the health trace and other one near CTRL and CAPS Lock traces. I solder a normal thin wire to these two stapler pins and voila, it came back to life.

If you are having the same problem, feel free to comment down. I'll see it in less than 24 hours since I'm actively searching for answers on stackoverflow!

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  • \$\begingroup\$ If it works, it works. For this I think I would have used copper foil tape with conductive glue. \$\endgroup\$
    – narkeleptk
    Aug 30 '19 at 23:56
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    \$\begingroup\$ Conductive Glue is a great idea! Although staplers were the only thing that I could find in the middle of the night. Also 15gr Conductive Glue is 30₺ here in Turkey. Maybe I can use it for future problems. \$\endgroup\$
    – Emre A
    Aug 31 '19 at 10:55

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