Copper Be Gone: The Chemistry Behind PCB Etching | Hacker News Reader

Copper Be Gone: The Chemistry Behind PCB Etching

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64 pointsrolph7 comments

This brings back fond memories to my first semester studying electronics. First practical, we got to draw a PCB and transferred the image to a copper plate with UV light. Then we dumped it in a solution to eat away the unfixated copper.

Second practical, we drilled holes and mounted sockets for ICs. Third, we soldered all components. By then we had all realized that we were building a PIC Micro programmer, which we would be using for the remainder of the semester to flash microcontrollers.

This was such a fun way to learn.

I wanted to make PCBs at home, but I only had a 3D printer, so I ended up mounting a pen on it so it could draw on a copper board where I wanted the copper to remain:

https://www.stavros.io/posts/make-pcbs-at-home/

It worked pretty well!

I find this method less mentioned but it works way better than the others and the chemicals are much easily sourcable , A fresh mixture of HCL (toilet cleaning acid) and hydrogen peroxide( available from pharmacy) works much faster than ferric chloride at etching .

True, but with this method you must be more careful than when using ferric chloride, in order to not inspire vapors from the etching bath, which may contain HCl.

Therefore this is better done outdoors or under a chemical fume hood.

In the industry, such etchings are always done under chemical fume hoods. At home, it is likely that you must work outdoors. My home has an open balcony, where I can do such operations.

Oh we used to do this in a bucket at in the hallway, just outside of the class room. This was about 15 years ago in Eastern Europe, for an electronics course. For bonus, the tracing paint was well after expiration date, so the result came out defective often, so we had to redo it. Fun times.

I used and avow that method. One thing I would like to know, though, is if it's essentially the same method as the "cupric chloride" one. I'm guessing if you reuse the previous etching solution and add fresh HCl and H2O2 (which I did) one should get both etching reactions.

In any case it works very well, and it is safe, something which commenters in another hackaday article some time ago were doubting.

For my first circuit board, I plugged my soldering iron into a Variac to run it cool, dipped it in beeswax like an ink pen, drew the pattern on bare copper board from radio shack, then etched in ferric chloride. Getting it working involved some hacking away at bridged traces, but I was super proud.

I think it was some analog guitar pedal circuit, which is what I would have been into at the time.

I discovered that a jar of ferric chloride lasted almost indefinitely if I aerated it, don't know the chemistry behind that.

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