Cupric chloride etching

cupric chloride

Cupric chloride is generally considered a better etchant even though it is not as well known as ferric chloride. [Rolan Yang] has a photoset of the process. Cupric chloride is usually sold as a photography chemical. The best feature is that the solution can be regenerated so you won’t be disposing of nearly as much etchant. I found a great page detailing the process for the hobbyist.


  1. liam says:

    Wow. We’re being spoilt for choice in the ghetto-etch department these days, and this guide is INSANELY detailed… nice!

  2. Satiagraha says:

    w00t first post!

    Anyways, what is it meant by “better”? does it etch corners cleaner or make it easier for thinner traces?

    How expensive is it compared to ferric?

  3. Darkcobra says:

    note that this hack links to two pages. the 2nd page (not the photoset) contains all the real info.

    if I’m reading this correctly, the solution is ‘regenerated’ by adding air, hydrochloric acid, and water; additional cupric chloride is not required because it makes more from the previously etched copper. with regeneration, you end up with more usable etchant with time!

    but there was another etching method featured a while back which used only hydrochloric acid and hydrogen peroxide. note that i haven’t used either that method (yet – but i will soon) or this method, but here’s some initial observations:

    1) The hydrochloric/peroxide etchant would be easier to use because it’s clear.
    2) The primary concern in disposal is the toxicity of metal compounds in the etchant. Hydrochloric/peroxide produces only as much copper as you etch away. Hydrochloric/cupric actually produces more, as you’re adding cupric to start, in addition to what you etch away. You’d have to regenerate it many times to minimize that starting penalty.
    3) Hydrochloric/cupric etchant requires more attention to properly mix and regenerate; compared to hydrochloric/peroxide which you just mix and discard.

    So, although the featured method is interesting, I don’t see any advantages for the average hobbyist over the hydrochloric/peroxide method. Correct me if I’m wrong!

  4. Darkcobra says:

    also, since hydrogen peroxide is listed as one possible regenerants, it may be that the hydrochloric/peroxide etchant actually *makes* a regeneratable hydrochloric/cupric etchant after etching, without having to have the cupric on hand in the first place..?

  5. stoned says:

    And what is the price of CuCl2? Sigma says 47 $. Iron chloride is half the price! And what about Sodium/Ammonium persulfate? No stains? Faster? Cheaper! Can anybody please explain why no hacks are posted? This is not a hack this is just a standart procedure description. Well, wait, no, not even that it is only a hand full of pictures. But it is new! No, wait google has 13.000 entries for (“cupric chloride” etchant). Congratulations! New all-time low!

  6. Beanwaur says:

    you can regenerate feric chloride by electroplating the copper out of it.

  7. andrew says:

    “well, wait, no, not even that it is only a hand full of pictures”

    wow, stoned, thanks for the great enlightenment. had you been paying attention, you would have noticed darkcobra’s earlier post:

    “note that this hack links to two pages. the 2nd page (not the photoset) contains all the real info.”

  8. andrew says:

    oh and by the way, stoned, “cupric chloride” comes up with not 13, but 272000 entries on google. but don’t worry, you’re only about 271987 off.

    please, stop putting down every post, especially when your comments are completely wrong.

  9. andrew says:

    [edit] google results for “cupric chloride” etchant = 13100, not 13.000.

  10. japroach says:

    I think I will stick with ferric chloride. It’s $7 cdn for 500mL at the local electronics store, and that lasts quite a while (it can be reused many times).

    Only problems are it needs to be heated (easy for small boards, just boil some water and immerse a glass container in it), and that it will stain.

    I guess if you want to stretch out the bottle a bit more, instead of having empty areas on the board use ground fill or hatching.

  11. smloo says:

    “[edit] google results for “cupric chloride” etchant = 13100, not 13.000.”

    A period is often used as the thousands separator in European countries. Why would anyone write 13_point_000? So just quit yer nitpicking and lighten up everyone! :-)

  12. asdf says:

    Ya, im agreeing with japroach on this one. you cant beat a 16 oz. bottle from a local ratshack for 7 bux of ferric chloride. theres no mixing of fluids, and if its a small enuf board you dont really even need to heat it, as long as its room temperature (so no etching in a cold garage).

  13. Bat says:

    Erm..nice work..maybe next time I can do it myself..thanks!

  14. andrew says:

    hello the international standard is a space now, everyone lets get along periods and commas are stupid

    lol jk alright i guess i thought he meant 13 because he said it was a “new all-time low” but forget it, lets get along then :)

  15. nds-flash says:

    Too bad my mama told be not to play with any acids.

  16. PacketMonkee says:

    all your BASE are belong to us
    I’m so funny.

  17. smilr says:

    RE: smloo

    One would write 13.000 to provide 4 significant digits (rightmost digit in a number is considered suspect (rounding / measurement error) and therefore not trusted or “significant” – this way one is certain down to the hundredths place that the decimal part is 0.

    Then again, it’s kind of hard to have “part” of a google result query, so specifying decimals for a count of google results returned doesn’t make sense in this context. ::shrug::

  18. steve says:

    go for it stoned ur far to inteligent for this lot i have the same problem they all so thick that they carnt understand us as for the hack all i can say is next plz

  19. brainwarp says:

    Now I just need to figure out how to incorporate an LED into this and it will be perfect

  20. hi says:

    how about illuminating the liquid with a high power led

  21. steve says:

    go on leds are wonderfull we need more somthing to brighten our hackaday pmsl

  22. brainwarp says:

    #20 now your cooking, wonder if a defcon badge would do the trick. hehehe

  23. mike says:

    maybe you could use the etchant as a wetcell in a battery and make a heating pad for the etchant with it and have its power level shown by a lit led.

  24. strider_mt2k says:

    If you ground up a famous director could you make Kubrick Chloride?


  25. grayskies says:

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