Does H2O2 and HCL eat away paper - Page 1
Forum section: electronics / general

author: MrOmnos
author_rank: Frequent Contributor
timestamp: January 31, 2018, 07:02:01 pm
content: So, guys I toner transferred a board and it came out pretty good.But there is this annoying paper stuck to it which won't go away. I have used tooth and pins to remove it but its too time consuming and the paper is stuck pretty good. Anyone here etched with H2O2 and HCL, does the chemical eat away the paper?Or I need to remove all of it?

author: microbug
author_rank: Frequent Contributor
timestamp: January 31, 2018, 09:15:20 pm
content: I'm willing to bet that a HCl / H2O2 combination will dissolve paper fairly well. If you're worried about it you could use a bit of water on a cloth to gently scrub away the paper — but I'd just give it a try, toner and copper clad is cheap.

author: Yansi
author_rank: Super Contributor
timestamp: January 31, 2018, 09:50:57 pm
content: Won't dissolve paper too much.Don't make PCBs with toner transfer. The results are anything but reliable and barely usable for SMT stuff. Photographic method for diying PCBs is nowdays so cheap and widely available in terms of material and chemistry, I wouldn't never consider anything else.

author: microbug
author_rank: Frequent Contributor
timestamp: January 31, 2018, 11:26:57 pm
content: Quote from: Yansi on January 31, 2018, 09:50:57 pmFor a PCB that size, I'd go with Oshpark. It's cheap and the quality is far, far better than anything you can do at home.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 31, 2018, 11:35:15 pm
content: No, that makes chlorine gas and etches the copper besides.You can try >= 50% sulfuric acid, which will hydrolyze the cellulose, turning it to a gel at first, then becoming soft enough to wash away. Tends to affect the toner, though.H2O2 + sulfuric acid will etch copper, which might be more pleasant than HCl.I think HCl is usually recommended just because it's so easy to get. It's just about the most noxious option -- moreso than FeCl3, which is a salt (if a rather acidic one), rather than pure volatile acid.Sulfuric acid is (readily?) available as drain opener, check the label.Remember "do as you oughta, add acid to watta" applies to sulfuric acid. Muriatic acid doesn't matter because it's already a solution. Sulfuric acid is rather more aggressive, because it's high concentration (>92% usually), and this precaution must be followed.Tim

author: janoc
author_rank: Super Contributor
timestamp: January 31, 2018, 11:52:13 pm
content: Quote from: MrOmnos on January 31, 2018, 07:02:01 pmYou can completely ignore the paper that is stuck to the toner. That will not cause any problems and will get removed when the toner is removed.The paper in-between the tracks needs to be removed - for me the easiest method was to soak the board in the water and the use a kitchen brush that is used to wash dishes to brush it away. Or an old toothbrush will work too.The hairs of the brush will get between the traces and will tear apart and remove the wet paper easily. The toner won't get damaged if you have done the transfer properly but don't apply too much pressure. There is no need for it.I would avoid chemicals for this because they may both attack the copper or even the toner. Not to mention the danger - concentrated sulfuric acid, as suggested above, is certainly neither easy to get nor something you want to tinker with unless you have a lab training and proper safety equipment. If you spill that it will eat through pretty much anything and heavens help you if you drop the bottle ...And mixing sulfuric acid, especially concentrated one, with hydrogen peroxide... just don'tThat mix is called a Piranha solution for a very good reason - it literally eats away anything organic. Not only the paper on your board but also your fingers, face, whatever it gets on. Oh and mixing it is extremely exothermic and if it gets in touch with organic matter (e.g. grease or solvent) it could cause an explosion due to being a very strong oxidizer. Stay away from this!https://en.wikipedia.org/wiki/Piranha_solution

author: tautech
author_rank: Super Contributor
timestamp: February 01, 2018, 12:13:59 am
content: Quote from: MrOmnos on January 31, 2018, 07:02:01 pmYou can't really say that until it's etched.QuoteDon't make the same mistake and try to use that same paper again.You need one with a better sealed face so the toner doesn't penetrate into the paper but instead sits on top.There's a bit of trial and error until you get a paper that works good and releases the toner cleanly.Even when they don't lift away clean, don't hurry the removal and instead drop it all in a saucer of water for a hour or two. Lift carefully and while wet any remaining paper strands can be rubbed away with a finger.QuoteFollow janoc's advice and get all the copper that needs be removed clean and exposed to the etchant.There's some more info on etching in this post and thread:https://www.eevblog.com/forum/beginners/smallest-pitch-for-home-made-pcb-that-is-doable-for-experienced-guys/msg668246/#msg668246

author: Yansi
author_rank: Super Contributor
timestamp: February 01, 2018, 12:50:59 am
content: Drain cleaners are NaOH, definitely not sulphuric acid.

author: Cerebus
author_rank: Super Contributor
timestamp: February 01, 2018, 01:11:36 am
content: Quote from: Yansi on February 01, 2018, 12:50:59 amNope, both are used, and sold as, drain cleaners.I've a 1l bottle of 96% w/w H2SO4sitting here labelled 'Drain Cleaner' in big letters and also two 500gm bottles of NaOH pellets labelled 'Drain Cleaner'. Both bought for their inate chemical composition, not as drain cleaners.

author: timelessbeing
author_rank: Frequent Contributor
timestamp: February 01, 2018, 01:17:38 am
content: Quote from: Yansi on February 01, 2018, 12:50:59 am

author: timelessbeing
author_rank: Frequent Contributor
timestamp: February 01, 2018, 01:28:16 am
content: This stuff works a bit better.But photoresist will probably give better detail.or make your life easier and buy prelaminated board stock.

author: Dave
author_rank: Super Contributor
timestamp: February 01, 2018, 02:43:25 am
content: Quote from: Yansi on January 31, 2018, 09:50:57 pmThat's just your experience. I've had reliable and consistent results with toner transfer for things like 0,5mm pitch footprints.Granted, I now just order PCBs from China, but I've made my fair share of PCBs with toner transfer back when PCB fabs weren't so cheap.I usually soak my boards in water and let the paper get fully saturated. The majority of the paper usually peels off with little to no force. The remnants come off nicely by scrubbing the area with my fingertips. If the toner gets any damage whatsoever while doing it, you need a hotter laminator.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: February 01, 2018, 09:29:14 am
content: Be careful mixing chemicals. Especially H2O2 or nitric acid with anything organic. A surprisingly large number of combinations are explosive.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 01, 2018, 10:29:14 am
content: If you can afford nitric acid, you can afford commercial PCBs easily.Incidentally, toner itself probably nitrates reasonably well, at least to a low degree.Tim

author: janoc
author_rank: Super Contributor
timestamp: February 01, 2018, 10:39:53 am
content: Quote from: T3sl4co1l on February 01, 2018, 10:29:14 amPlease, don't give such chemistry ideas to newbies here. You may know how to handle the chemicals and what will happen when you mix them but most people don't, especially not the ones asking for ideas.I still cringe at the idea you have suggested earlier of the OP trying to mix sulfuric acid and hydrogen peroxide, especially in higher concentrations of either. Granted, you didn't tell him he should mix them concentrated but you didn't say the opposite neither and I can perfectly imagine someone trying that, not knowing any better.That's literally advising a newbie how to kill themselves, whether by a very likely explosion or getting splashed with the solution reacting violently when mixed.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 01, 2018, 11:32:01 am
content: I'd be surprised if someone is able to find H2O2 of any meaningful concentration for less than Chinese PCBs cost. 3% is rather innocuous stuff, enough to tingle modestly-noble metals or the odd patch of skin, but not especially dangerous.For those curious, 30% H2O2, concentrated sulfuric acid, and perhaps a dab of catalyst (usually ferric sulfate, IIRC), makes a wonderful solution that devours anything organic. It's a chemist's favorite last resort, akin to the mechanic's torch: got glassy carbon deposits that just won't come out of your already-hard-to-clean condenser? Burn the shit out of them with Satan's unholy ballsweat. Good as new!Quote from: janoc on February 01, 2018, 10:39:53 amBut, I suppose just as disturbing -- if not moreso -- would be the notion of someone running across some random post,on the internet,and convincing themselves that they should subsequently take an action, which is counter to that "common sense" thing they should've learned from an actual mother and father, or from teachers at school...Possibly related reading:Tim

author: janoc
author_rank: Super Contributor
timestamp: February 01, 2018, 06:10:48 pm
content: Quote from: T3sl4co1l on February 01, 2018, 11:32:01 am30% peroxide is still available in many places if you search for hair dresser supplies. Heck, even Amazon sells a half a liter bottle for about $30, with free shipping (won't post links here, who wants it will easily find it - it took me 30 seconds on Google).Quote from: T3sl4co1l on February 01, 2018, 11:32:01 amSorry, that's complete bull. There is a difference between someone finding a random article on the Internet by googling and then hurting themselves because of ignorance/stupidity and something thathas been expressly recommended as a solution to the OPs problem by someone apparently knowledgeable in the matter- i.e. you in this case.That's just washing hands of responsibility in this case.

author: Yansi
author_rank: Super Contributor
timestamp: February 01, 2018, 06:24:46 pm
content: I find that washing hands of off responsibility absolutely fine. Everyone should behave on his own behalf. If some is stupid, his fault, not mine or yours.It seems it is people like you why EU has become what it has become: A pile of stupid paranoia of anything garbage. You seem you would be glad to forbid anything, aren't you?

author: timelessbeing
author_rank: Frequent Contributor
timestamp: February 01, 2018, 06:40:37 pm
content: janoc, calm down. I think you misread.Quote from: IanMacdonald on February 01, 2018, 09:29:14 amA very clear warning from Ian.Quote from: T3sl4co1l on February 01, 2018, 10:29:14 amHere, Tim is saying it's easier to just order a PCBNobody was suggesting to use Nitric. But even if they did, the word "acid" and the scary labels on the bottle should be enough to tell you that it might be dangerous stuff , and that maybe you should take some precautions and do a little research, no? If they know how to use an internet forum, they probably know how to look for Nitric Acid on wikipedia.

author: Cerebus
author_rank: Super Contributor
timestamp: February 01, 2018, 10:28:29 pm
content: Quote from: Yansi on February 01, 2018, 06:24:46 pmCan we please have a little less of thead hominemknocking of country/territory, especially from someone who's obviously so embarrassed by where they come from that they feel the need to conceal it.

author: Ampera
author_rank: Super Contributor
timestamp: February 01, 2018, 10:32:01 pm
content: Not sure how this would affect this, as I am not familiar with the process, but have you tried burning it?

author: timelessbeing
author_rank: Frequent Contributor
timestamp: February 01, 2018, 10:54:33 pm
content: since toner is a thermoplastic, I would hazard a guess and say burning it would ruin the print. Not to mention oxidize the copper.I wonder how the OP is getting along...

author: Yansi
author_rank: Super Contributor
timestamp: February 01, 2018, 11:02:57 pm
content: Quote from: Cerebus on February 01, 2018, 01:11:36 amHave done a little research. You won't buy a sulfur acid drain cleaner. At least no where I live. Very unlikely you will find one.

author: timelessbeing
author_rank: Frequent Contributor
timestamp: February 01, 2018, 11:10:54 pm
content: We don't know where you live.I can go get some sulfuric acid drain cleaner right now at hardware store.

author: Ampera
author_rank: Super Contributor
timestamp: February 01, 2018, 11:31:31 pm
content: Quote from: timelessbeing on February 01, 2018, 10:54:33 pmYeah, I had a feeling.

author: Cerebus
author_rank: Super Contributor
timestamp: February 01, 2018, 11:39:51 pm
content: Quote from: Yansi on February 01, 2018, 11:02:57 pmLooks like you need to need to brush up on your research skills.IsaidI actually possessed both H2SO4and NaOH in bottles labelled 'Drain Cleaner' and yet you somehow seem to doubt my word. So, a photo:

author: Yansi
author_rank: Super Contributor
timestamp: February 01, 2018, 11:44:17 pm
content: Quote from: Yansi on February 01, 2018, 11:02:57 pmCan't you read?They do NOT sell these here. Hence my confusion about acid drain cleaners.It would be easier here to buy a bottle of chemically pure concentrated sulphuric acid in a chemistry store, than to find an acid drain cleaner.

author: timelessbeing
author_rank: Frequent Contributor
timestamp: February 02, 2018, 12:00:23 am
content: We can read, but your wording is awkward."Very unlikelyyouwill find one."Anyway, I wish we had chemistry stores here.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 02, 2018, 12:05:22 am
content: Quote from: Cerebus on February 01, 2018, 10:28:29 pmIf it matters, he doesn't seem to be very shy about location:https://www.eevblog.com/forum/chat/new-ebay-web-page-design-(are-web-designers-stupid-or-what)/msg1411132/#msg1411132Tim

author: Cerebus
author_rank: Super Contributor
timestamp: February 02, 2018, 12:11:09 am
content: Quote from: Yansi on February 01, 2018, 11:44:17 pmYes, I can.Quote from: Yansi on February 01, 2018, 11:02:57 pmI'm prepared to cut people a lot of slack for their English on here, there are a lot of non-native speakers.If your intent is to say that "It can't be bought as that where I live, but obviously it is sold as that elsewhere" that's fine, but you phrased itexactly wrongif that's your intent. Itsoundslike a gainsaying of the several people who have told you that Sulphuric Acid is sold as a drain cleaner. You ought to understand how people might take that in a negative way, your previous snarky comment about denizens of the EU does kind of set you up as needlessly confrontational sounding. As does "Can't you read?" as an introductory riposte - next time try "You misunderstood, let me rephrase that".

author: TMM
author_rank: Frequent Contributor
timestamp: February 02, 2018, 01:13:50 am
content: A long soak in water and a gentle rub with your finger (not fingernail) should remove the paper. The blue "Press N Peel" transfer film is much nicer to work with than paper transfers. That said, chinese PCB fabs are so cheap these days that I wouldn't bother unless you need the board the same day.

author: james_s
author_rank: Super Contributor
timestamp: February 02, 2018, 01:30:17 am
content: Quote from: Yansi on January 31, 2018, 09:50:57 pmI've achieved very consistent results with toner transfer, I routinely do SOIC packages and 0603 parts with good yields, I've done stuff as fine pitch as 0.5mm TQFP but that is really pushing the process. Don't be so quick to write it off, it's largely just a matter of getting the process dialed in which is the case for any method.I send out most of my boards these days but when you just need one board and want it today, it's hard to beat etching yourself.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 02, 2018, 03:58:12 am
content: I thought I was in total agreement with Yansi, until a few seconds of Googling showed me that both acid and base drain cleaners are sold side by side here in the US. The same 93% sulphuric acid stuff. Makes me wonder how often Joe Householder gets a real surprise when he buys two brands and dumps them in the same drain.

author: timelessbeing
author_rank: Frequent Contributor
timestamp: February 02, 2018, 05:56:06 am
content: hehe, I'm picturing a geyser of garburator/dishwasher remains coming out of the kitchen sink. Or maybe hairballs if it's the bathtub.

author: Brumby
author_rank: Unknown
timestamp: February 02, 2018, 07:41:23 am
content: Quote from: timelessbeing on February 02, 2018, 05:56:06 amIf someone puts one type down the drain first and then the other ... I would be picturing a geyser featuring strongly of the second product. I wouldn't find that too humorous if their face was too close.

author: janoc
author_rank: Super Contributor
timestamp: February 02, 2018, 09:26:28 am
content: Quote from: timelessbeing on February 01, 2018, 06:40:37 pmYou didn't read his earlier comment higher up in the thread:https://www.eevblog.com/forum/chat/does-h2o2-and-hcl-eat-away-paper/msg1414873/#msg1414873There he explicitly recommended using a concentrated sulfuric acid to remove the paper, and together with hydrogen peroxide to etch copper as being "more pleasant than HCl with peroxide".

author: janoc
author_rank: Super Contributor
timestamp: February 02, 2018, 09:42:48 am
content: Quote from: Brumby on February 02, 2018, 07:41:23 amI actually find the idea of a sulfuric acid being used as a drain cleaner rather strange. Not questioning its existence just the idea of using it in this way.A hydroxide (lye) is used as a drain cleaner because it turns the various greases, hair and similar organic material into something resembling soap and lets them dissolve in water (that's why the instructions say to let it work for several minutes and then flush with water), without damaging the piping.Acid would dissolve some clogs as well but it will also attack any metal and clay (unless vitrified) pipes and any cemented joints (shouldn't be used but are you sure what the contractor has used?) which are still quite common. That's probably asking for a nasty leak later on. Is there a particular use case where an acid-based cleaner would be preferable to use? Genuinely curious as I haven't seen an acid based drain cleaner before.And, labeling both products as "Drain cleaner" is a crazy idea, indeed. If someone mixes these two in their sink thinking "drain cleaner as drain cleaner", they are in for a nasty and dangerous surprise

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 02, 2018, 12:41:56 pm
content: Sulfuric is not recommended for iron pipes, which are still quite common here in the US.Likewise, lye is not recommended for PVC, which is quite common here. Though the amount of damage it can do, I don't think is very much. Lye would seem to be the safer bet overall. Downside: lye is far more dangerous to the eyes.Tim

author: timelessbeing
author_rank: Frequent Contributor
timestamp: February 02, 2018, 08:22:11 pm
content: Quote from: janoc on February 02, 2018, 09:26:28 amYes, he says HCl produces unpleasant, volatile chlorine gas. He also said Sulphuric is more aggressive. From his post I get a clear impression that there is an element of risk with all the chemicals being discussed. While I think that using strong acids to remove a bit of paper is overkill, I see no reason for alarm over his post. I believe that the best way to prevent accidents is to educate, not try to shield people from facts.I think the OP's board must be finished. Now that your safety concerns have been noted, and we have thoroughly, I think we can let this go.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 02, 2018, 11:58:46 pm
content: In case anyone was wondering, sulfuric acid isn't very scary. It's certainly not a put-holes-in-anything, Aliens green goop thing. Nothing can do that, outside of thermite (for a little while) and molten reactor core (for a while longer*).*Though it won't be green. Radioactive glow, in air, is blue anyway, but the incandescence will be much more intense so you won't notice that. And then you die from radiation exposure a few minutes or hours later, so, please don't watch nuclear meltdowns in person.If you don't have any thin skin, scrapes, cuts, sores, that sort of thing, and your hands aren't particularly clean (i.e., equipped with natural body oils and such), sulfuric acid actually takes quite a long time to act on your bare skin. You have entire minutes to leisurely make your way to the sink, wash it off, and resume activities. Really, the only reason you should be proactive about it, is just so you don't forget about it later! It's a much greater hazard to your clothing, cotton in particular, which will be charred (concentrated acid) or hydrolyzed.And these consequences are easily avoided by wearing gloves, and extra layers of clothing (loose fitting, so the drops don't absorb through layers and touch your skin -- as it happens, a lab coat is perfectly designed this way!).Acid in the eyes is also not as dangerous as it sounds. Acid washes away easily with tears; you already have this experience from cutting onions! Hardly pleasant, and no excuse not to wear eye protection -- but unlikely to be permanent. Bases, on the other hand, actively dissolve eye tissues, and don't wash away so easily. You are very likely to survive a droplet of acid in the eye. You are very likely to lose an eye from a droplet of concentrated NaOH.As you might tell, I am very practical and knowledgeable when it comes to safety. The first step is understanding. If you don't, or can't, understand the properties of what you're working with, you probably shouldn't be working with it.That ought to be sufficient, as a headline for the safety content of this thread!As for PPE and procedure, the best safety isnotthe strongest protection. The best safety is the easiest to use. Forcing everyone to wear full body positive-pressure suits, just because they're handling some glacial acetic acid? No one will bother! That's a stupid rule. Asking them to put on a lab coat and safety glasses, which are handy at the lab entrance? Now you're talking.HTH,Tim

author: IanB
author_rank: Super Contributor
timestamp: February 03, 2018, 12:17:44 am
content: Quote from: T3sl4co1l on February 02, 2018, 11:58:46 pmJust to add a counterpoint, sulfuric acid is significantly more nasty than hydrochloric acid. The reason being that if you spill hydrochloric acid it evaporates quickly, and after it has evaporated it is gone.In contrast, if you spill sulfuric acid, even dilute acid, then the water evaporates but the acid doesn't. The result is that you get a drop of concentrated sulfuric acid left behind that sits there for a long time and eats away at whatever it is in contact with. If you get a drop on your clothing you will later find a hole in your clothes. If you spill it on a wooden surface, you will later find a charred scar on the surface. If you spill it on your skin you will later find a burning pain and a wound unless you act really quickly.Do not underestimate how nasty sulfuric acid is. When it is concentrated it eats away and dissolves anything organic. Which is why it is used as a drain cleaner.

author: vk6zgo
author_rank: Super Contributor
timestamp: February 03, 2018, 12:21:29 am
content: A possibility for removing the paper is Mineral Turpentine.It is weird stuff, in that its mechanism for removing things isn't normally by dissolving them.I had some amalgam of glue & carpet rubber backing to remove from a wooden floorAll the commonly suggested things just dissolved the mix & turned it into a gooey mess.Turps got under it it broke the bond to the floorboards.Of course, it may dissolve the toner, but the only way to find out is to try.

author: Cerebus
author_rank: Super Contributor
timestamp: February 03, 2018, 12:27:02 am
content: Quote from: T3sl4co1l on February 02, 2018, 11:58:46 pmSave that hot, concentrated sulphuric acid will start to eat skin on contact. My ex has a scar on her shoulder where she got splashed with hot (circa 60C) H2SO4when the top of a Kjeldahl flask came off while she was shaking it. This was wearing proper lab PPE and she was bundled into the emergency shower mere seconds later but that was still long enough to damage skin enough to leave a permanent 1/2" x 3" scar.Lets notover-minimize the risks. They are oft-times exaggerated but let's not make it sound like all H2SO4exposures can be treated as merely urgent. Temperature and concentration make the difference between a leisurely stroll to the lab sink and a head-long dive for the emergency shower.By the way, the easy way to spot chemists on a university campus is look for the characteristic small 1-2mm circular holes in their jeans that have frayed white edges. Classic giveaway that you sprayed a few drops of dilute H2SO4around and didn't notice it land on your jeans.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 03, 2018, 12:42:49 am
content: Quote from: Cerebus on February 03, 2018, 12:27:02 amYes, I was referring specifically to STP "unless otherwise noted". Also, the skin on your* hands is thicker than over most of your body, which helps with casual instances.Needless to say, the above situation would suck (and did)!*Yours? Bluh, English phrasing being English. I of course mean: "mine at least, but YMMV".QuoteIndeed. Think I still have a few shirts in circulation with a clustering of holes about table-level...Also had a few shirts with holes around the shoulders, from way back when I was doing home foundry with charcoal and wood. The sparks are pretty.... from a distance.Tim

author: Cerebus
author_rank: Super Contributor
timestamp: February 03, 2018, 01:50:46 am
content: Quote from: T3sl4co1l on February 03, 2018, 12:42:49 amIf you don't mind sounding like Prince Charles the standard formula for that is to refer to "one's hands". I don't like the sound of that phrasing, but I will use it when I really do want to avoid the "you" construction. e.g. Online I might say "if one is a complete idiot" when replying to someone who I suspect will take "if you are a complete idiot" as anad hominemremark rather than a general one.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 03, 2018, 02:41:57 am
content: Yes, that phrasing should've come to mind.Tim

author: james_s
author_rank: Super Contributor
timestamp: February 03, 2018, 08:33:18 am
content: Sulfuric acid can be pretty scary stuff. I used to have some that was quite strong, putting a few drips on a cotton rag would smoke and quickly burn holes in it. Even the diluted stuff in car batteries can be dangerous, I had some leak out of a battery I carried and the thing that made me realize what happened is parts of my pants and tshirt started falling apart and my leg got itchy.