Simple PCB etchant made from chemicals you can put in your mouth


[Stephen] often finds the need to make his own PCBs at home, and when he got the urge to do some etching recently, he realized that he was fresh out of “Ferret Chloride and Bureaucratic Acid*.” Undeterred by his empty chemical cabinet, he poked around in his kitchen mixing together anything and everything that might have the ability to strip copper from a PCB.

Now, we don’t necessarily recommend this course of action, but it seems that he finally hit upon a winner. He discovered a formula that can be made at home from simple and safe household ingredients which does the job quite nicely. A fair warning however, standard ferric chloride disposal procedures need to be followed when using this solution.

If you want to know what he concocted in his kitchen as well as the chemistry behind it, you will have to visit his site, we won’t ruin it for you. You can however, see the solution at work in the video we have posted below.

*His joke, not ours

63 thoughts on “Simple PCB etchant made from chemicals you can put in your mouth

  1. Well I found out that if you use the old solution in a weed sprayer and dose the leaves of those unwanted and out of controll plants like the wisteria we are trying to get rid of the leaves turn brown and die real quick. The plant is self becomes prety stressed and new leaves seem to be red but it continues to grow.

    I suspect the solution may have been a little to potent and needs to be watered down as the cupric acid needs to get to the internal system of the plan.

    However the Deadly Nightshade died within 2 days and has not come back. WOOHOO. THis stuff has succeeded where Roundup did not.

    And no I have not contaminated the ground as I now have grass growing where the nightshade was. ALso I burn the vines afterwards just to be sure.

    Wisteria is EVIL!

  2. @Mechno
    I’ll corroborate it. For what it’s worth. Some troll posted the same thing on the guy’s site. Ignore them.

    I actually tried it. Not a hoax. Definitely works.

    I used 2 parts straight from the bottle vinegar, and 1 part 6% peroxide. The article was using 1:1 vinegar and 3% peroxide. Someone mentioned diluting the vinegar, which might have stopped it working. The vinegar in the bottle I got was already at 5% acidity, which might be were the confusion set in.

    Add the board, add salt, and agitate.

    It is slow. My attempt took about an hour to get all the unwanted copper off, but it does work. I think I may have added the salt too slowly though.. It was my first ever PCB etch, so I am not the best authority on how well the process can work, or how efficient it is in comparison to others.

    Try it yourself. Worst case scenario, you are out a tiny amount of money, best case, you have found a supply of cheap etching solution available at any supermarket and chemist.

  3. I just tried it on a small breakout board I designed for a Nokia LCD connector. I just poured roughly equal amounts of peroxide and vinegar then dumped in some salt. It started working right away and you can see it. The reaction is quite fast and will coat the board in residue which I wiped off when it got too thick. The final etch came out very clean, one of the cleanest etches I’ve ever had, and I think I took it out too early. I think this works better than ferric chloride. I disposed of it by dissolving a soda can tab in, it formed copper metal precipitate and then I diluted it down the drain.

    Being a clear (later clear-blue) solution it is easy to see the etching progress (unlike ferric chloride which is thick and dark).

  4. I tried this just now. Made an experimental PCB with a permanent marker. It fizzed right through the one-layer coat, ate half the copper under two-layer coats, and left small holes in three-layer coats. I will have to use something stronger than permanent marker next time when I want actual electrical connections, but at least I can etch PCBs now.

    @whyhowwhen: thanks for the tip! I tried that too, but didn’t have any aluminum foil so I used soda cans. The reaction seemed too slow so I added soda before the copper precipitated out. I realized I did something wrong when the liquid foamed up and felt gooey and turned even more blue, so I added more vinegar and the foam dissolved and the precipitation reaction continued.

    Some notes on decuprification of the liquid product by means of aluminum metal. The soda can tabs worked moderately well, but cut-up walls of the soda can didn’t seem to do anything. Then I realized they were only reacting at the edges because aluminum metal likes to oxidize when exposed to air. I cut up a few more pieces, but this time I sanded them, and these ones worked much better.
    I suspect that aluminum powder would work the fastest, but it would be difficult to work with unless it came in sealed porous bags like some brands of tea. Then both the aluminum powder and copper precipitate would remain contained by the porous bag.

  5. I tried this and I found it takes forever and it undercuts the traces. Hydrochloric acid and peroxide is quick and cheap. Ferric chloride produces no fumes but costs more. 5% acetic acid and 3% peroxide will take all day as it is almost all water.

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