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Since my early hobbyist days when ferric chloride felt expensive, I designed my PCBs with as much copper left on the PCB as possible so my acid solution could last as long as possible. Since then, I have made it a habit to make copper pours where possible.

But now it occurred to me that maybe I am being environmentally unfriendly. Now that I use professional PCB manufacturers, is it ultimately better or worse for the environment to leave copper on my PCBs or to etch it off?

Elliot Alderson
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Ole Wolf
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    "*But now it occurred to me that maybe I am being environmentally unfriendly'*"? Huh? How does your logic follow? – DKNguyen Mar 01 '23 at 14:31
  • I don't think it is to concerning to have excess copper on your pcb if you are making small volume (1-10 PCBs); if you make hundreds of thousands to millions of pcs, then all the copper is going to add up. – cats are the best Mar 01 '23 at 14:31
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    @DKNguyen what he means by environmentally unfriendly is that now he has more copper on the pcb then copper that could be used elsewhere – cats are the best Mar 01 '23 at 14:34
  • @catsarethebest Is that what he means? If so then the balance is between waste etchant and copper (which we assume is recycled). – DKNguyen Mar 01 '23 at 14:34
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    @DKNguyen: "catsarethebest" is right. I was thinking that in a professional manufacturing plant, the copper may be recyclable so leaving it on my PCB could mean I'm hogging up a valuable resource. – Ole Wolf Mar 01 '23 at 14:45
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    The manufacturers will recover the copper being etched off your PCBs so don’t worry about it. – winny Mar 01 '23 at 14:57
  • @winny I certainly expect they do, but I am wondering whether their copper recovery process is more environmentally friendly than leaving the copper on the PCB and (eventually) reclaiming the copper from the PCB. – Ole Wolf Mar 01 '23 at 15:04
  • Then leave the copper on the board? It will end up as e-waste and be recovered there instead down the line. – winny Mar 01 '23 at 15:07
  • @winny He is talking about hogging up all the copper because he isn't etching it off. – cats are the best Mar 01 '23 at 15:09
  • @catsarethebest I afraid I don’t understand the difference. OP has two options, etch it away or leave it on. Environmentally, the copper will either be recovered now or later. – winny Mar 01 '23 at 15:18
  • @winny so which one is better? – user253751 Mar 01 '23 at 16:20
  • In industry, cupric chloride is probably the etchant of choice. During etching, the volume of this actually grows, proportional to how much copper is etched. It needs chemical balancing also. The copper ions could then be chemically deposited out of solution, but I have no idea if this is done (assume so.) Cupric chloride is some nasty stuff that can't ever go down a drain (very poisonous to aquatic life) so they must recover the copper. – rdtsc Mar 01 '23 at 17:01
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    If it was bad for you to leave more copper on your boards, then the fab would charge you more the more copper was left, so until they do, I wouldn't worry about it. – Glen Yates Mar 01 '23 at 17:05

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It really depends on what etching chemical they are using to etch. I'm only familiar with ferric chloride. I would surmise it would be more environmentally friendly to leave it on the PCB, as this would create less copper solution. But on an industrial scale it's not likely to matter because they likely use processes to recover the copper or at least turn the etching material into a product that is not hazardous.

At home however, you'd want to leave it on because etching copper would create more byproducts that are harder to reduce.

Voltage Spike
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