They're forming perchloric acid. Yes, you want more peroxide if that's the route you want to take- you need two peroxides for each HCl. H2O2 has a molecular weight of 34g/M, HCl is about 72g/M, so you need 4g of peroxide for every gram of HCl to get maximum effectiveness- these weights refer to the pure substances, that has to be corrected when they're diluted in solution.
Personally, I'd avoid it- it's nasty even for an etchant. FeCl3 or ammonium persulfate are pretty nasty, too, but less so. All of this requires some significant safety equipment- I wouldn't handle this stuff without heavy duty rubber gloves (not kitchen gloves!), a rubber apron, a chemical fume hood, and full face shield.
Personally, I'd avoid it- it's nasty even for an etchant. FeCl3 or ammonium persulfate are pretty nasty, too, but less so. All of this requires some significant safety equipment- I wouldn't handle this stuff without heavy duty rubber gloves (not kitchen gloves!), a rubber apron, a chemical fume hood, and full face shield.
I use homemade copper chloride for etching. It can be rejuvenated indefinitely by adding a few drops of peroxide after each etch and HCL once in a while.
It's made by dissolving copper wire in HCL (muriatic acid) and 35% hydrogen peroxide until the proper density is achieved. The acid is available at building supply stores. I purchased the peroxide at a health food store, at $16 for a liter. Because so little is needed, it should last many years.
It's made by dissolving copper wire in HCL (muriatic acid) and 35% hydrogen peroxide until the proper density is achieved. The acid is available at building supply stores. I purchased the peroxide at a health food store, at $16 for a liter. Because so little is needed, it should last many years.
Let me reiterate: this stuff is DANGEROUS. Unless you have full chemical safety equipment, you're nuts to try any of this stuff. Commercial etchant is bad enough.
Unlike direct-mains powered stuff, which is likely to kill others, playing with strong acids and corrosives is likely to just kill the fool who does it, so I have less sympathy. Darwin Awards, anyone?
Unlike direct-mains powered stuff, which is likely to kill others, playing with strong acids and corrosives is likely to just kill the fool who does it, so I have less sympathy. Darwin Awards, anyone?
Take a look at the MSDS sheet for copper chloride. It is about the same as ferric chloride. It is no more dangerous than using household bleach, drain cleaner or oven cleaner. You don't see women wearing full body armor and a face shield when they handle these, do you?
Nothing worth doing is completely risk free. Just take reasonable care.
Nothing worth doing is completely risk free. Just take reasonable care.
Thanks for the chemistry. So but are you are saying that the HCl in the muriatic acid and the H2O2 form perchloric acid, and it's the perchloric acid that reacts with copper? HCl certainly by itself reacts with copper. So what is the role of the H2O2?
Ferric chloride is not at all locally available to me (the Bangor, Maine area). Having it shipped to me now involves a surcharge for handling a hazardous material. In the past I have had FeCl3 shipped to me by UPS at regular ground rate.
Regards,
Pete
I used to use Ferric Chloride
When ever I'd need to make a board I would stroll on down to Radio Shack and pick up some Ferric Chloride because I didn't know any better. This stuff is a mess, it doesn't matter how careful I was I always got it on something. Stains everything it see's except glass, ruins anything metallic. I accidently got the tiniest drop on my stainless steel sink and washed it off instantly to come back later and find a round discolored spot that never leaves. And your not supposed to pour it down the drain either.
So anyway I stumbled across a site a years back that said to use hci and h202 parts 1:2. So I tried it and it worked great and after some experimenting I learned that parts 2:5 worked even better and the best part is you don't have to throw it out just keep topping it off with H202. And it’s clean, well cleaner then that ferric mess.
But like most Hazardous things people like me/us get involved in, don't do it if you’re not comfortable or can't read. I have gotten this on me a few times and I've just washed it off, no prob. It is a nasal/eye irritant though so proper ventilation. When I started using this stuff I would put my goggles and face mask on with a rain coat because I felt like a biolab tech but know I don't care. Use your noodle or stay away from the fun stuff.
When ever I'd need to make a board I would stroll on down to Radio Shack and pick up some Ferric Chloride because I didn't know any better. This stuff is a mess, it doesn't matter how careful I was I always got it on something. Stains everything it see's except glass, ruins anything metallic. I accidently got the tiniest drop on my stainless steel sink and washed it off instantly to come back later and find a round discolored spot that never leaves. And your not supposed to pour it down the drain either.
So anyway I stumbled across a site a years back that said to use hci and h202 parts 1:2. So I tried it and it worked great and after some experimenting I learned that parts 2:5 worked even better and the best part is you don't have to throw it out just keep topping it off with H202. And it’s clean, well cleaner then that ferric mess.
But like most Hazardous things people like me/us get involved in, don't do it if you’re not comfortable or can't read. I have gotten this on me a few times and I've just washed it off, no prob. It is a nasal/eye irritant though so proper ventilation. When I started using this stuff I would put my goggles and face mask on with a rain coat because I felt like a biolab tech but know I don't care. Use your noodle or stay away from the fun stuff.
I agree , if you take a few percautions it is the best and cheapest etchant you can get .....
I have been neutralizing my wasted acid with "PH Up" and water until it has a PH of about 4-5 then take it to the hazardous waste disposal at the recycling depo , though I flush small ammounts once in a while ...... PH Up is a highly alciline solution use for adjusting the PH in hydroponic fertilizer solution ......
I have been neutralizing my wasted acid with "PH Up" and water until it has a PH of about 4-5 then take it to the hazardous waste disposal at the recycling depo , though I flush small ammounts once in a while ...... PH Up is a highly alciline solution use for adjusting the PH in hydroponic fertilizer solution ......
Muriatic acid is HCl "hydrochloric acid." Copper is a noble metal and so does not react with HCl. The hydrogen peroxide is the oxidizing agent that allows the reaction.
A quick note to those in Bangalore, India.
I have had good success in making my own PCBs, with almost professional results. You can buy all the stuff you need locally. You will need to make a UV exposure unit with a UV tube and a stand to hold your board. You will also need a darkroom for the lithography. You can buy lith film and all the developing chems locally. The steps are:
1) Make your layout. Print it out on good photo paper, inverted.
2) Expose lith film and make a contact negative 1:1.
3) Develop the lith film. to get a negative.
4) Prepare the copper clad board.
5) Coat with negative photo resist (available locally). Has a delightful smell
6) Expose the film and board with the UV light unit.
7) Wash the board with the PR developer (nasty!)
8) Highlight with the blue dye chem.
9) Wash with water
10) Touch up defects with indelible marker
11) Etch with Ferric Chloride.
Two sided boards are do-able, provided you dont make any vias under inaccessible holes. Ive been using this technique for many years. The results are very good, tho I will probably die of cancer or some other dreadful disease.
vkj
I have had good success in making my own PCBs, with almost professional results. You can buy all the stuff you need locally. You will need to make a UV exposure unit with a UV tube and a stand to hold your board. You will also need a darkroom for the lithography. You can buy lith film and all the developing chems locally. The steps are:
1) Make your layout. Print it out on good photo paper, inverted.
2) Expose lith film and make a contact negative 1:1.
3) Develop the lith film. to get a negative.
4) Prepare the copper clad board.
5) Coat with negative photo resist (available locally). Has a delightful smell
6) Expose the film and board with the UV light unit.
7) Wash the board with the PR developer (nasty!)
8) Highlight with the blue dye chem.
9) Wash with water
10) Touch up defects with indelible marker
11) Etch with Ferric Chloride.
Two sided boards are do-able, provided you dont make any vias under inaccessible holes. Ive been using this technique for many years. The results are very good, tho I will probably die of cancer or some other dreadful disease
.vkj
Hi All,
You have to understand that SY is a professional, a mature expert in his field in fact. I was lucky to have spent a week with him some time ago, and in that week I was able to observe that he is not an over cautious person. I'd describe in as adventurous within safe boundaries.
The concern isn't really with people who have experience with handling chemicals, but rather with our younger members who may know enough to get themselves into real trouble. This happens with people starting out in life, and with people attempting to do things in a field that they were not trained in.
So what are we attempting to accomplish? Simple, before attempting any work with chemicals, voltage, etc ... do take the time to fully familiarize yourselves with all the dangers and cautions related to anything you wish to try. This applies to everything in life, including driving a car.
A comment was made that referred to household cleaning chemicals and "housewives" using them without prior training. Guess what? This is an example we were taught as what can happen when you aren't fully aware of what you are doing. Certain cleaning agents mixed together were reputed to be more effective for cleaning floors. The individuals who tried this all had a bad experience, and several died. They made chlorine gas and poisoned themselves. That was before the internet, just imagine how many could be killed today with a misguided suggestion in a similar way.
No one can control your actions remotely. All we can really do is direct your attention to a potentially deadly activity. Make no mistake, gases released with these chemicals can certainly kill you if not vented away from where you are working. You could even hurt or kill emergency responders by being careless. Please heed SY's warning and educate yourselves properly before attempting to experiment.
For the record, I mostly use Ferric Chloride for etching boards. Heat it slightly and agitate the solution for the best results. I put a top on the container while the boards are in etching to contain the fumes in addition to ventilation. I've tried other chemicals and return to Ferric Chloride because it works. It will stain your skin and clothing yellow. The cloth will disintegrate over a period of time, hence the warnings about proper attire.
-Chris
You have to understand that SY is a professional, a mature expert in his field in fact. I was lucky to have spent a week with him some time ago, and in that week I was able to observe that he is not an over cautious person. I'd describe in as adventurous within safe boundaries.
The concern isn't really with people who have experience with handling chemicals, but rather with our younger members who may know enough to get themselves into real trouble. This happens with people starting out in life, and with people attempting to do things in a field that they were not trained in.
So what are we attempting to accomplish? Simple, before attempting any work with chemicals, voltage, etc ... do take the time to fully familiarize yourselves with all the dangers and cautions related to anything you wish to try. This applies to everything in life, including driving a car.
A comment was made that referred to household cleaning chemicals and "housewives" using them without prior training. Guess what? This is an example we were taught as what can happen when you aren't fully aware of what you are doing. Certain cleaning agents mixed together were reputed to be more effective for cleaning floors. The individuals who tried this all had a bad experience, and several died. They made chlorine gas and poisoned themselves. That was before the internet, just imagine how many could be killed today with a misguided suggestion in a similar way.
No one can control your actions remotely. All we can really do is direct your attention to a potentially deadly activity. Make no mistake, gases released with these chemicals can certainly kill you if not vented away from where you are working. You could even hurt or kill emergency responders by being careless. Please heed SY's warning and educate yourselves properly before attempting to experiment.
For the record, I mostly use Ferric Chloride for etching boards. Heat it slightly and agitate the solution for the best results. I put a top on the container while the boards are in etching to contain the fumes in addition to ventilation. I've tried other chemicals and return to Ferric Chloride because it works. It will stain your skin and clothing yellow. The cloth will disintegrate over a period of time, hence the warnings about proper attire.
-Chris
Let me reiterate: this stuff is DANGEROUS. Unless you have full chemical safety equipment, you're nuts to try any of this stuff. Commercial etchant is bad enough.
Unlike direct-mains powered stuff, which is likely to kill others, playing with strong acids and corrosives is likely to just kill the fool who does it, so I have less sympathy. Darwin Awards, anyone?
Unfortunately that's not how it comes across. It sounds more like:-
NO USER SERVICEABLE PARTS INSIDE.
The electronicians don't want you fiddling with the electronics.
The doctors don't want you prescribing your own drugs (especially the ones that work)...
...and now... the chemists don't want you to play with their toys either.
Yes, it's crazy to use strong acids instead of ferric chloride, about as crazy as building a valve amplifier when you could go solid state.
A warning as to the dangers, and perhaps suitable precautions such as having some bicarbonate of soda on hand and working within range of a shower you can use as a drench would have sufficed. Given that pickling brass in acid is commonplace among steam engine enthusiasts, a post taking that attitude is just going to be ignored as over-the-top.
Oxidizing acids are a whole 'nother level of hazard. You don't understand that, nor apparently the difference between a strong acid and an oxidizing acid, but are happy to dismiss warnings from the pros (especially from a pro who says HE wouldn't do it, despite years of experience and training).
Feel free to go injure yourself, there's always more Darwin Awards to give out, but anyone with two brain cells to rub together should avoid perchloric acid like the plague.
Feel free to go injure yourself, there's always more Darwin Awards to give out, but anyone with two brain cells to rub together should avoid perchloric acid like the plague.
Actually I have as much medical knowlege as my doctor if not more , On several occations my doctor has prescribed me medications that are contraindicated and I had to point out to him in his office that these 2 medications can not be taken together , He even once refused to perscribe me a medication because he said it contained an anti-imflamitory that I couldn"t take and I had to proove to him in his office useing his computer that he was pattently wrong and it did not contain an anti-inflamitory but an analgesic ......
The moral of the story is that a piece of paper hanging on the wall doesn"t allways denote competance nor inteligence ....... Lucky for me I don"t have any paper on my wall so I can allways plead ignorance ......
The moral of the story is that a piece of paper hanging on the wall doesn"t allways denote competance nor inteligence ....... Lucky for me I don"t have any paper on my wall so I can allways plead ignorance ......
Actually I have as much medical knowlege as my doctor if not more , On several occations my doctor has prescribed me medications that are contraindicated and I had to point out to him in his office that these 2 medications can not be taken together , He even once refused to perscribe me a medication because he said it contained an anti-imflamitory that I couldn"t take and I had to proove to him in his office useing his computer that he was pattently wrong and it did not contain an anti-inflamitory but an analgesic ......
The moral of the story is that a piece of paper hanging on the wall doesn"t allways denote competance nor inteligence ....... Lucky for me I don"t have any paper on my wall so I can allways plead ignorance ......
Gee, that post inspires confidence in me. Someone who can't even write proper English asserting they have "as much medical knowledge" as their doctor.
The reason you don't have a "piece of paper" is because you did not go to university for 5 to 6 years and have to successfully complete hard examinations and then do a residency to further establish a competency to treat people. It is also the reason why you won't be allowed to treat people.
As much as I'm not a big personal fan of SY, I am prepared to accept his high levels of competency in a field in which he is qualified and has practised.
As to pleading ignorance, no need; I don't believe there is any ambiguity about it.
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Where does it say that writing competancy relates of other forms of competancy ?? Like I said I"m still smarter than my doctor and you should see his writing pluss I can speak 3 languages and he barely speaks one ....
I would have you know that I had to quit school at 9 because my father was murdered durring the revolution in 79 I had to get a job to support my mother and brother and wasn"t able to go to school , many of the teachers were murdered or jailed and schools were closed , my uncle was executed in the town square ........
I would have you know that I had to quit school at 9 because my father was murdered durring the revolution in 79 I had to get a job to support my mother and brother and wasn"t able to go to school , many of the teachers were murdered or jailed and schools were closed , my uncle was executed in the town square ........
In my experience the rate of etching is controlled by the concentration of the hydrochloric acid. Hydrogen peroxide is only available in fairly dilute solutions (for safety reasons). Adding a lot of peroxide solution will dilute the hydrochloric acid and reduce the rate of etching. Anyway you only need to add a little bit of peroxide to remove the copper. If the etching solution starts going a dark color add another little bit of peroxide. Keep the solution when you have finished. You may find that the next time you need to etch a board there is no need to add peroxide because of the amount of copper (2) chloride (which is itself an etchant) that has built up in the solution. I would suspect that more concentrated hydrochloric acid solutions more rapidly dissolve the copper (1) chloride (which is barely soluble in water) that is initially formed in the etching process, thus exposing fresh copper to attack. I did read somewhere that adding some citric acid will also speed things up and again that would help dissolve copper (1) chloride .
LOL
Getting back to the topic... 31.45% HCl and 3% H2O2 aren't nearly as dangerous to bodily health as these same substances at 90%+ concentrations. So I'm curious to know some more about these lower concentrations mixed in a 1:2 ratio. Do you mind, SY? Because I've used just such acid to etch boards.
Not LOL'ing your story, Minion. Rather the previous posts.
Getting back to the topic... 31.45% HCl and 3% H2O2 aren't nearly as dangerous to bodily health as these same substances at 90%+ concentrations. So I'm curious to know some more about these lower concentrations mixed in a 1:2 ratio. Do you mind, SY? Because I've used just such acid to etch boards.
Not LOL'ing your story, Minion. Rather the previous posts.
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