Hi, First post here from me. I normally use the muriatic acid and hydrogen peroxide mix to etch my pcb’s. I just used a plastic tupperware type container and gently rock it back and forth until its complete. I was and still am going to make a small motor with a cam to do the rocking for me but that is another story. I bought this etchant tank removed link to step up from my method and let the air bubbles do the manual labor as opposed to me having to do it. The instructions say to use ammonium persulfate or ferric chloride. Does anybody have a tank like this and know if my muriatic acid and hydrogen peroxide mix will be safe to use without damaging the tank? I know there are many other etchant home brews like citric acid and salt and vinegar etc but I like the fact my etchant is reusable and I don’t have to worry about hazardous disposal etc. I have never used ammonium persulfate before but it seems like it is not reusable although I don’t know for sure.
Thanks,
Dave
edit: The link was removed but it’s the Etchant Tank ET20 so you should be able to look it up.
Well, I already figured out that I can use my etchant while waiting for my first post to be released from moderation. That said, any comments on this subject would still be nice for a future read.
Thanks,
Dave
Very cool tank i have use ammonium persulfate or ferric chloride and just about every system for pcb prep and resisting i still use a old plastic tub and lid and manual timers and shaking
Tom
@voltage I’ve used Ferric Chloride for as long as I remember and have settled with it. I’ve tried other methods as well but never liked them since to many chemicals are required, the photoresist to me (is also) way too many stages to follow. And never bothered shaking the solution to speed up the etching even though some sort of automatic shaking system would be more than welcome. But on the other hand I’m an “old timer” and like to leave the things unfold on their own pace. If it takes longer…so be it. But having said that usually any double sided board I’ve ever etched never took more than 20-25 minutes and I’m more than happy with it.
@tomswork I like using the muriatic/peroxide mix no problem if done safely. Its a 2 parts peroxide to 1 part muriatic acid and depending on the strength it can be adjusted when necessary by adding one or the other. As you use it, it becomes cupric chloride and that makes it even better. It can be used indefinitely this way so you don’t have to worry about disposal. You can see through it pretty well to monitor the progress too. I have been using a plastic container but wanted to step it up a bit to more easily do 2 sided boards and get started with SMT stuff. I have a few hot plates and also built one of those Controleo3 reflow ovens that is just waiting for me to try although I am wondering about 2 sided boards in that setup. I guess populate the side with more components and use the oven and finish side 2 with an iron or hot air gun. There must be a standard way but I will get there as I progress.
Do you find the ferric chloride to be reusable and if so, for how long? Isn’t it hard to see through when etching? No undercut or is it user friendly if you leave a pcb in for too long? What about things nearby the solution, do they rust like with the muriatic/peroxide method if not careful? On the double sided board do you have to flip it or will it etch both side at the same time. I don’t mind my method but I could be tempted to buy a gallon of ferric chloride just for testing.
@voltage I’ve used Ferric Chloride for as long as I remember and have settled with it. I’ve tried other methods as well but never liked them since to many chemicals are required, the photoresist to me (is also) way too many stages to follow. And never bothered shaking the solution to speed up the etching even though some sort of automatic shaking system would be more than welcome. But on the other hand I’m an “old timer” and like to leave the things unfold on their own pace. If it takes longer…so be it. But having said that usually any double sided board I’ve ever etched never took more than 20-25 minutes and I’m more than happy with it.
I have been using ferric chloride. and hate the smell of muriatic acid.
Larry – N7LUF
I find almost all the etching fluids can be reused. I use a dap of glue on smt parts that im using solder paste on or putting in a oven
Tom
@voltage Any etchant you chose to use will stain/rust things near by if you’re not careful to keep them well away. Any PCB while etching will create gas bubbles in the process therefore will tend to keep the PCB “afloat” and only partially etch the side the “top side”. So, my method is to attach (put on top of the PCB) some weights (plastic weights) IE: plastic standoffs of somethings similar so the gained weight is just enough to drag the PCB down a little (so it stays submerged at al times) and perhaps you can even “shake” a little (now and then) if you wish (I don’t). When etching PCBs I usually do it outside the house (in free space) so artificial ventilation is not a concern. As for how many times the Ferric Chloride is reusable well… nobody can answer that since it highly depends on the amount of etching you do and the thickness of the copper layer you need to etch the PCBs physical size etc. As you probably have guessed by now, various PCB manufacturers make PCBs using different thickness for the copper layer. Usually the cheap and cheerful Chinese ones tend to “cheap out” on copper therefore using a very thin layer of copper (ER: but for most of the normal low current battery operated applications is more than ok to use such boards. Those boards will etch fairly quick (within 15-18 minutes usually with a new unused or new-ish etchant). And of course if you keep shaking it will go even faster (8-12 minutes). Now, leavening the PCB extra time after the etching is done (in my experience) rarely hurts a board. But this highly depends on what method you’ve used to transfer the design. Say you’ve used a more rudimentary “uneven” method to transfer the toner such as a hot iron then the chances are it will hurt the board. Same thing will happen if you’ve used a hot laminator but either the laminator isn’t hot enough (at least 190 degrees Celsius!) or you did not allow for enough number of passes (thru the laminator) or the PCB was somehow finger greasy before laminating then the PCB will be hurt. But again if you rigorously keep “certain standards” such as super clean (squeaky clean PCB surfaces and never touch with fingers) before laminating and use a properly “temperature tuned” laminator the results should be more than satisfactory. NOTE: do not “ever” even touch (with fingers) the freshly printed art work before applying to copper and also don’t waist any time between printing the design and applying it to the PCB ready for the laminator since the resulting toner transfer method is also “time sensitive”. The quicker you do things the stronger the toner will stick to the board therefore more resilient to the etching agent used. So, as you can see lots of little details will definitely make the difference. Good luck. PS: “never ever” use any “third party” toner re-fills with your laser printer. Use original cartridges “ONLY”. This way you’ll get the best toner transfer results. Good luck.
Larry,
You’re not supposed to smell it. 😀 I use mine outside under my carport and there is usually a breeze that I use to my advantage on where to stand. But I agree, muritic acid is pretty strong stuff if you get a wiff. 😋
I have been using ferric chloride. and hate the smell of muriatic acid.
I find almost all the etching fluids can be reused. I use a dap of glue on smt parts that im using solder paste on or putting in a oven
Tom
I found some “sodium” persulfate that I bought a few months back and that is different than “ammonium” persulfate but I think that can also be used as an etchant. More research is need on that as I may have bought it thinking it was something else. Anyway . . . When you are using a bit of glue is that for double sided pcb work or just in general? And what kind of glue do you use?
Thanks for the info. I always do my etching outside under the carport and usually when there is a breeze. I am very safe and wear protective glasses and gloves etc. Originally I bought some 2 oz single sided copper clad CEM-1 boards and they seem to take a lttle longer to etch and go much faster if I rock the container. I have just recently bought some 1 oz FR4 double side boards (Paramount brand) and I believe for the small hobby type stuff I do they will be fine and etch much faster.
I use a modified Apache AL13P laminator and run the board through 5 times at 350 degrees. Works great using the yellow paper from ebay. I use a HP 1022 LaserJet and that make a nice resist. I clean my pcb with Bar Keepers Friend and wash with Dawn then finish with acetone. I have read here on the forum where Sam adds an extra layer of TRF (Toner Reactive Foil) on top of the resist for added protection from the etchant. I never tried it but I might. I never did any of my own silk screen layers either but I want to try that in the future too.
@voltage Any etchant you chose to use will stain/rust things near by if you’re not careful to keep them well away. Any PCB while etching will create gas bubbles in the process therefore will tend to keep the PCB “afloat” and only partially etch the side the “top side”. So, my method is to attach (put on top of the PCB) some weights (plastic weights) IE: plastic standoffs of somethings similar so the gained weight is just enough to drag the PCB down a little (so it stays submerged at al times) and perhaps you can even “shake” a little (now and then) if you wish (I don’t). When etching PCBs I usually do it outside the house (in free space) so artificial ventilation is not a concern. As for how many times the Ferric Chloride is reusable well… nobody can answer that since it highly depends on the amount of etching you do and the thickness of the copper layer you need to etch the PCBs physical size etc. As you probably have guessed by now, various PCB manufacturers make PCBs using different thickness for the copper layer. Usually the cheap and cheerful Chinese ones tend to “cheap out” on copper therefore using a very thin layer of copper (ER: but for most of the normal low current battery operated applications is more than ok to use such boards. Those boards will etch fairly quick (within 15-18 minutes usually with a new unused or new-ish etchant). And of course if you keep shaking it will go even faster (8-12 minutes). Now, leavening the PCB extra time after the etching is done (in my experience) rarely hurts a board. But this highly depends on what method you’ve used to transfer the design. Say you’ve used a more rudimentary “uneven” method to transfer the toner such as a hot iron then the chances are it will hurt the board. Same thing will happen if you’ve used a hot laminator but either the laminator isn’t hot enough (at least 190 degrees Celsius!) or you did not allow for enough number of passes (thru the laminator) or the PCB was somehow finger greasy before laminating then the PCB will be hurt. But again if you rigorously keep “certain standards” such as super clean (squeaky clean PCB surfaces and never touch with fingers) before laminating and use a properly “temperature tuned” laminator the results should be more than satisfactory. NOTE: do not “ever” even touch (with fingers) the freshly printed art work before applying to copper and also don’t waist any time between printing the design and applying it to the PCB ready for the laminator since the resulting toner transfer method is also “time sensitive”. The quicker you do things the stronger the toner will stick to the board therefore more resilient to the etching agent used. So, as you can see lots of little details will definitely make the difference. Good luck. PS: “never ever” use any “third party” toner re-fills with your laser printer. Use original cartridges “ONLY”. This way you’ll get the best toner transfer results. Good luck.
Use Sodium Persulfate and only make what you need for the moment. It’s harmless compared to all the other stuff suggested here.
ferric chloride is nasty as h*** to handel if you spill some.
When in doubt use a microcontroller.
Thanks for the info about the safety with this etchant. I will give it a try soon to see how I like it for simple quick prototyping.
Use Sodium Persulfate and only make what you need for the moment. It’s harmless compared to all the other stuff suggested here.
ferric chloride is nasty as h*** to handel if you spill some.
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