Make 10 Etchants for Copper Printed Circuit Boards

Make 10 Etchants for Copper Printed Circuit Boards


Warning: These reactions uses corrosive acids, gloves should be worn. Additionally some produce toxic gases and should be performed outside or in a fume hood. Greetings fellow nerds. In this video we’re going to show how to make ten etchants for copper printed circuit boards. Some are better than others but since you, my viewers, are worldwide you will have to choose which ones you can make with your locally available materials. I recommend trying a few different ones and finally settling on the one that works best for you. Now I know there are a lot more etchants out there that I have not listed here like persulfate and permanganate based etchants but I’ve selected these ones as being the most straightforward to make. So let’s get started. First in the peroxide family of etchants is hydrogen peroxide along with an equal amount of concentrated hydrochloric acid. This etches pretty easily and is the most popular homemade etching solution. What’s happening is the hydrogen peroxide is oxidizing the copper and reacting with hydrochloric acid to produce copper chloride. A disadvantage of this etchant is that it decays and unused etchant loses strength in storage. But a great thing about this etchant is that it makes useful copper chloride that can be used as another type of etchant that I’ll detail later on in the video. The second peroxide family etchant is hydrogen peroxide and sulfuric acid. This also etches rather quickly and produces less fumes than the hydrochloric acid version. What’s happening is the hydrogen peroxide is oxidizing the copper and reacting with sulfuric to produce copper sulfate. Like other peroxide etchants this one also decays in storage and loses strength. But an advantage of this method is that the copper sulfate can be converted back into sulfuric acid and copper metal. Making this etchant very easy to recycle. The third peroxide family etchant is hydrogen peroxide and sodium bisulfate. Sodium bisulfate is a little easier to get than sulfuric acid as it’s sold as a pH lowering chemical for swimming pools. It works like the sulfuric acid version and produces a combination of copper sulfate and sodium sulfate. The downside is that it is extremely slow. And takes hours to do what the other etchants can do in minutes. Another disadvantage is that unused etchant also decays in storage. Nonetheless it’s very easy to make. It can also be electrochemically recycled. Now we start the metal chloride family of etchants and the first and most famous member is ferric chloride. I already have a separate video on exactly how to make it so i won’t repeat it here. The chemistry works by oxidizing the copper to copper chloride while the ferric chloride is reduced to ferrous chloride. A great advantage is it does not decay in storage and unused etchant can last indefinitely in an airtight container. Recycling is possible but requires extra chemicals and a lot of effort. It might be more straightforward to dispose of it. The second metal chloride family etchant is copper chloride and hydrochloric acid. You can simply evaporate or boil down the spent peroxide and hydrochloric acid etchant from earlier into a highly concentrated solution, or react fresh copper chloride with hydrochloric acid. The hydrochloric acid is necessary since it reacts with the copper chloride to make tetrachlorocopper ions. It is these ions that react with copper and comproportionate into dichlorocopper ions. The great advantage of this etchant is that it can be easily regenerated by bubbling in air. In fact in storage it not only lasts indefinitely but actually regains strength as it absorbs air. So it’s even easier to recycle than the sulfuric acid based etchants. I’ll do a whole video on the chemistry of copper chloride etchants so to keep this video short i’ll stop here The third metal chloride family etchant is copper sulfate and hydrochloric acid. This is actually an alternative way to make the tetrachlorocopper ions. The sulfate ions don’t interfere and the reaction works much the same way. It can be stored indefinitely and can also be regenerated by air and recycled just as easily. This is useful for those of you who can’t get hydrogen peroxide to make pure copper chloride. The next family is the chlorine family of etchants. So named because they produce chlorine so you have to use these either outside or in a fume hood. The first is hydrochloric acid and bleach. It works by reacting with copper and producing copper chloride and sodium chloride. While not very efficient if you have little else this might be your only choice. Like i said before this will also produce chlorine gas so be careful. It also decays in storage so unused etchant loses strength. This etchant can technically be regenerated and recycled but doing so is so expensive and complicated that you’d probably be better off starting with one of the metal chloride etchants. It’s thus more economical to simply dispose of this etchant if you’re using it. The second chlorine family etchant is manganese dioxide and hydrochloric acid. The manganese dioxide can be obtained from zinc-carbon type batteries. Whoa, that almost got away from me there. As you can see the initial burst of chlorine can splatter the chemicals so be careful. This method works by reacting with copper and producing manganese chloride and copper chloride. Of course this also makes chlorine as seen earlier. Like other chlorine etchants it is unstable in storage and will decay. As with the bleach version recycling is possible but not economical and should simply be disposed of. The nitrate family of etchants begins with the simplest nitrate source, dilute nitric acid. This reacts with the copper to produce copper nitrate and nitrogen monoxide. Nitrogen monoxide is quite toxic so this must be done outside or in a fume hood. When the etchant stops working it can be boosted with sulfuric acid to reactivate the remaining nitric acid. After all the nitric acid is depleted the etchant is dead and the copper sulfate can be electrochemically recycled. Unused etchant can be stored indefinitely without losing strength. The last etchant is a mixture of a nitrate salt like potassium nitrate and hydrochloric acid. This is actually a crude version of aqua regia and can even etch gold if you’re so inclined. The reaction produces copper chloride as well as side products and by products of metal salts, nitrogen monoxide, chlorine and nitrosyl chloride gases. This definetely needs to be performed outside or in a fume hood. The etchant is also unstable in storage and recycling is also not economical. So there you have it, ten ways to etch copper printed circuit boards. Now after you’ve depleted your etchants you’ll eventually end up with copper containing chemical waste that’s horrible for the environment and likely illegal where you live to simply dump down the sink. But I’ll show methods of recycling, reprocessing and disposal in a later video. Thanks for watching. In this video we’re going to chemically process various etchants for safe disposal and recycle or regenerate those that are feasible to do so. In this video we’re going to make ferric chloride. A useful chemical to etch copper clad printed circuit boards.

71 Comments

  1. hello I was wondering if you could make a video on how to precipitate gold from hydrochloric acid & h-peroxide etchant?

  2. very interesting.
    Would definitely like to see the NurdRage version.
    I think it was on Hackaday that used hydrogen peroxide + HCl (as muriatic acid) to make a regenerative etchant…or was it on instructables…I forget.

  3. ok i may have no clue in any of this guys vidios of what the hell he is even saying but it looks cool so thats why i am whatching i am more of a computer gamer / tech nerd then a science person lol  whats a shocker i see people in the comments here know what this guy is talking about and stuff dam you guys make me  feel stupid lol 

  4. NurdRage, thank you for posting your videos! They are very useful and well done. I have a question though: can you make a video or help show me how to properly dispose of concentrated chemicals such as muriatic acid, ferric acid hydrochloric acid ect. thanks!

  5. Hello,

    I have some H2SO4 but its only 50%. But my H2O2 is 30%.
    Is it correct if i use the following formula?
    2mL H2SO4 (50%)
    1mL H2O2   (30%)
    8mL H2O

  6. yep…but none of them seems to be as clean as the ferric chloride reaction ! I mean … Manganese dioxide+Hydrochloric acid…that was a bit messy :/

  7. Actually sodium persulphate is pretty cheap on the webpage I order from, I stick with that (and it can be used in exotic magnesium flash powder as it is a strong oxidiser)

  8. I tried first metod with H2O2 and HCl but it isnt work i've got 30%Hcl and 30%H2O2 which temperature is the best ?  I tried 33ml 3% H2O2 and 33ml 30% HCl – it isnt work

  9. so what kind of etchant is this: http://www.ebay.com/itm/200g-Copper-clad-palte-CCL-PCB-blue-environmental-protection-etchant-brand-new-/221461079030?pt=LH_DefaultDomain_0&hash=item33901be3f6

  10. another suggestion for future video: selective corrosion, e.g. nickel, tin , gold or alloys are preserved while copper is etched away. It is the process used in pcb industry.

  11. I'm looking for a copper etchant that doesn't attack tin, and vice versa. Could you make a video explaining that?

  12. I have been using sodiumpersulfate with an air bubbler for years. After use I add sodiumhydroxide to fell all copper as oxide. The copper goes in a jar and the neutral sodiumsulfate water can go in the drain. No nasty fumes and I can order both chemicals by the kilo online.

  13. hello . I need etchant that is fast and leaves very less undercut . heard dutch mordant( HCl + potassium chlorate) works best can anyone corelate .

  14. will you make a video about recovery/dispose of Metal salts? maybe disposal of these etchants and a extra video about overall disposal?

  15. Copper (II) Chloride can be neutralised with sodium bicarbonate (makes a green sludge), or simply place wire wool into the solution until all the copper has stuck to it.

  16. What I am still looking for is a good simple cycle for etching. Like electroplating out the copper, and then being able to reuse it forever, only filtering it from time to time, or refill a bit chemicals now and then.

  17. I just made a BIG OBSERVATION (I am roockie) but i learnt about electrolysis and plating, i attached +ve to copper and submerged into vinegar – peroxied solution and what was taking hours is done in minutes, No idea what happened, care to explain? . just got this idea and tried 😛

  18. Olá Nurdrage!
    What kind of compound do you get when you evaporate the CuCl4 ²⁻ + H⁺ solution?
    H2CuCl4 (s) ?

    Because I've tried many times and it always ended up as a wet mess of needle-like crystals.

  19. I heard it was possible to anodize with a solution of Water and Sodium Bisulfate. and i have 2 questions about this. since i wanna use this as a method of anodizing the aluminum of a cpu heatsink

    1.i wanna have a much safer way of anodizing then having a tub of sulfuric acid around. so would something like this actually work to do so?
    2.will a sodium bisulfate and water mixture at a ratio of 40 grams of NaHSO4 to 160ml of water be harmful to copper during the anodization process or even before being anodized as i am unable to remove the copper heatpipes the heatsink comes with without damaging the copper?

    sorry for a random question… but i figured this question be best asked on a video based around Sodium bisulfate

  20. +NurdRage Can you please make a video about copper deposition on non-metallic surface like plastic and glass to be later plated using electricity and if possible the method would be easy to be done at home. the reason for that people (I am one of them) want to make copper plating for making double sided pcb at home but to plate the walls of holes in the pcb with copper(which is fiber glass) to make it condactive is not something everyone can do !!
    Thanks

  21. Hi,i have a lot of liquid ferric chloride fe2cl3,but i am having storage problem as it takes too much space,please provide a tutorial on liquid to evaporation of ferric chloride…india,uttarakhand

  22. Printed Circuit Board shops usually use Ammonia/Copper/Chloride bath and Reoxidized by Air. Can cool the bath to drop out Copper Amine Chloride complex as Crystals or can plate out the Copper. We treated the Copper waste solution (alkaline) with Sodium Borohydride and filtered out the Copper.

  23. Surprised Potassium Persulfate wasn't tried, it is a common (Walmart carries it) pool treatment chemical. Or how about Cyanuric Chloride (pool chemical for controlled release of Chlorine in pools)?

  24. Great Video! Only miss an approximation of how long these etching cycles took. For one you said that it is extremely slow, but how long did e.g. the Nitric acid take?

  25. Hi NurdRage. Thanks for this video. It help us a lot. Another important etchant used to make PCBs is Ammonium Persulphate that can be made by an electrolysis of a solution of Sulphuric Acid with Ammonium Sulphate. Could you please show us how to make it that way? Is it very complex?

  26. @NurdRage I use Ferric Chloride to etch steel (and stainless steel).

    Would adding HCl acid to the weak/spent etchant and then bubbling O2 re-constitute the Ferric Chloride?

    Thanks!

  27. Just wondering if you could make one using OxiClean (Sodium percarbonate) and HCl? Sodium percarbonate allegedly breaks down into hydrogen peroxide and sodium carbonate when mixed with water. The problem that I see is that the sodium carbonate is the same stuff that is used to develop and strip the photoresist from the board. However, would the HCl neutralize it so it is inert? The OxiClean is considerably cheaper around here than the high % H2O2.

  28. Thank you! thank you! thank you! for all of these electronics chemistry videos Nurd Rage.

    Seriously, you've played a major role in helping me discover my interests in PCB design and prototyping. I have been goofing around with electronics since becoming partially disabled in 2014. I've gone from goofing around with copy and paste arduino code to hacking old junk, to designing and etching my own circuits. I've watched this and several of your other uploads a dozen or more times. I have been playing with a container of ferric chloride I was given from RadioShack before they went belly up. I'm finally to the point where I want to try etching some larger panelized designs that are close to A4 sized transparencies. Today I was given a container of muriatic acid from lowes, some 3% hydrogen peroxide, some steel wool, and I'm back here for notes! I also have an old container of tarnex to try that tinning solution recipe you cooked up… yeah I'm that slow… as a gimp it takes forever to get things done. I really really appreciate the references you've made here.

    One problem I'm having is the unknown concentration of my old ferric chloride from RS. I don't know if I should try to heat it to evaporate/concentrate it or modify it somehow. Even the last 1/3rd of my bottle of fresh solution took around 45min to etch a 5cm × 10cm double sided design. Most people that I've watched or read about say that etching with ferric chloride should take around 15-20min. How does an amateur go about characterizing the quality and strength of their enchant? I don't expect an answer here or anything. This is simply intended as a positive feedback blurb. I'm just sharing a challenge incase you or anyone else thinks this kind of thing is worth addressing.
    I'm sure you have a laundry list of things you'd like to make content about.
    Another chemistry experiment I was curious about recently is trying to play with making a transistor using doped materials. I was watching Robert Baruch, on the channel by the same name, reverse engineering a 74 series logic chip at the die level. He was talking about a way to dye the p-channel doped materials during his last live stream. That got me curious about what other transistor effects could be made at home or even in the average lab. It's just something to think about if your interested in that kind of thing 😉
    -Jake

  29. I wonder if any alkalic solution also exist. Maybe ammonium-hidroxyde what is stinky though but also copper I and copper II complex exist.

  30. Why so little importance to naoh + hcl? wouldn't it produce salted water + copper? That would be about the cheapest method to etch for many of us living where hydrogen peroxide costs an arm and a leg. I'm not a particular fan of storing chemicals at home because of the kids, so ferric chloride and others are out of the list. A shame you didn't give more info like times or proportions.

    I'll try more or less what I see on the video and hope the chlorine produced doesn't cause much harm the ozone. After all I'll only be using it every once in a while. Thanks for sharing, though!

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