Etching a Circuit With Toilet Bowl Cleaner




Introduction: Etching a Circuit With Toilet Bowl Cleaner

I needed something cheap and easy to etch my circuit-boards with. After some experimentation, I came up with a simple method to etch PCBs using "The Works" toilet cleaner. Before we start though, let me state that this is my first instructable, and I would like any advice you have. I am not responsible for any damage or injury you cause. This acid takes longer to work than most others, but it is less corrosive too. It took almost one hour to etch our sample piece. We are not going to etch an actual circuit, but test a sample. This can be used on any copper clad circuit board you want to etch.

Step 1: Getting Ready

What you will need:

1.The Works or any toilet bowl cleaner that has a
hydrogen chloride concentration of 20% or more.

2. Hydrogen peroxide.

3. Pliers.

4. A plastic or glass container( NO METAL!)

5. Gloves

6. Safety glasses

7. Something under you're work-space

8. A clean work-space

Step 2: Igor, Hand Me the Works!

I've found that "The Works" works best(no pun intended). Now, I'm no chemist, but I believe it's because The Works uses hydrochloric acid. You can buy it at almost any grocery store. We are also going to need some hydrogen peroxide, you can buy this at most drug stores. Now pour the same measure of peroxide and The Works into you're container (the peroxide first).

Step 3: Now, Lets Etch!

Okay, now put you're board copper-side-up in the solution, and wait...

Step 4: Working, Working...

After about a half hour, your concoction should be a green/blue tint. This is good, this means the copper is eroding, also bubbles should be forming above the board.

Step 5: ... Done!

After an hour the copper you didn't want should be gone, if not, wait fifteen minuets or so. Otherwise, take your pliers, and pull out you're etched PCB! Put it and your pliers under running water quickly, unless you don't like ordinary pliers.

Step 6: Thanks!

I would appreciate any comments, questions, or ideas on this. I hope this instructable helped you.



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    22 Discussions


    3 years ago

    food for thought: would adding a fish tank bubbler speed the process up? I've seen it done on larger scale boards, so why wouldn't of work here?

    I'm trying this right 2 boards in a fairly large amount of etchant, considering how cheap it is to make.

    Seems to etch very slowly, but it seems to be working. If all goes well, I'll have a stepper controller soon.

    I think i am right in thinking that if you were gona etch a pcb board you can get special pens and mark the circuit on the copper then put it in the acid and everything will go except where the pen is then you can just sand off the pen and you have your board? a, i correct? mdog

    2 replies

    No "special" pen required. Just use a fine tipped permanent marker. If you can still see copper through the line you need to let it dry and go over it again. You could buy this or you could realize what it really is and buy it yourself for a quarter of that price.

    Actually a *proper* etch resist pen is not the same, it's a lacquer based marker which produces a thicker coating that is also more durable.

    i have a question: Im doing a pcb with an permanent marker and a virgin pcb board.

    if i put the pcb (the circuit is marked with permanent marker) to the formula,will it work? or I need to Stamp it?

    regard from Chile

    I tried it on a board last night, it took all night! This isn't working very well. But I believe you could pour it down the drain, that's what it's made for right?

    3 replies

    These are actually both the same idea just getting the Hidrochloric acid from different sources. I recommend going through the above link anyway it has some very good explainations and some reasonably detailed discussions of the chemistry involved which could help troubleshoot.

    Also it has some good discussions of the risks involved in messing around with this stuff which I recommend anyone attempting this read. They are significant but easily mitigated.

    Aside from the toxicity issues this solution is actually made to dissolve copper which your pipes (some of them at least) might actually be made of. 0.0!

    The Toilette bowl cleaner on it's own is supposed to be flushable but a significant change happens when you mix them together.

    it is the 1st time when I try ,it is god for this a toilet bowl cleaner that has 15-30%?

    Right, so we know how to remove copper. Have you tried etching circuit-boards with this yet? If so how well does it work? L

    how is this better than the ferric chloride?

    either one you use is corrosive and has to be disposed of properly.

    they are both powerful corrosive chemicals, and if you flush or rinse them down your drain there going to f*** your pluming up...

    6 replies

    I think he means the end product which contains copper salts you shouldn't put down your drain. That's what concerns me, anyway- putting drain cleaner down your drain doesn't worry me too much :P

    Wait... I just saw Bongmaster's comment, which reminded me that this is the reusable sort of etchant that doesn't get depleted (or rather can be "refuelled" with more acid). That is worth mentioning- you don't have to get rid of the used etchant, just add more acid and air.

    "Some local authorities may also permit the disposal of ferric / Edinburgh Etch solutions down the drain if they have been properly neutralised, and highly diluted. To neutralise an Edinburgh Etch or ferric chloride solution add a strong sodium carbonate solution gradually to this; (you may also use a used stripping solution as the neutralising agent). In a harmless fizzing reaction carbon dioxide is produced. Allow this to settle before adding more sodium carbonate. Once the solution no longer fizzes when soda ash is added neutralisation is complete. This can be confirmed by a pH test showing a pH value of seven. After that dilute with plenty of running water and discard."

    Edinburgh etch is the common name for this if you want to look it up.

    Copper salts can kill plants-it was used to clear sewer pipes of tree roots-and can kill fish, so don't dump it in a storm drain or on the ground. Probably not good for a septic tank if you have one. This small a batch isn't going to hurt a municipal sewage system.

    I think the concern here is of pouring the solution down the sink drain, which might have PVC connections, instead of the toilet, which it is designed for.

    And you think that the sink uses a different plumbing system than the toilet? (Well, if you have a grey water recovery system, it would.) While some houses are plumbed with cast iron up to the 50's or so, most have pvc pipes-which is one of the plastics that the toilet cleaner containers are made of...