| lgehrig4 |
Hi,
I purchased an etching kit from RadioShack for a small amp project. I cleaned the copper on both sides and followed the directions to a "T", but it did not work. The directions say to leave it in the solution for about 20min. In 20min almost no copper left the board. I left it in over an hour and still not all the copper dissolved, however some of the areas that were not supposed to dissolve did.
Does anyone have any advice, tricks or knowledge that they can pass on to me? The directions are lame and I'm sure there is more to it than they explain.
Thanks
Jeff |
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| jackinnj |
it helps if the etchant is warm -- but don't warm it on a gas stove since the reaction releases hydrogen.
i now prefer to use hydrogen peroxide and muriatic acid. the hydrogn peroxide can be bought at the drugstore for under a buck for a quart, the muriatic acid is at the hardware store -- used to clean stone, it's pretty nasty stuff (Dilute hydrochloric acid). The HCl acts to accelerate the oxidizing effect of the H2O2 -- it takes less time than ferric chloride. |
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| richie00boy |
| If you had to expose the board to UV light to create the mask then I'd say that you either didn't expose it for long enough or didn't clean all the residue off after developing. |
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| RetroAudio |
| jackinnj - how many parts acid to peroxide do you use? |
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| nick_g_evans |
I have just started to do this myself also. My first couple tries were hideous, but my third was a clean success!
As you have probably heard, there are several ways to mask the copper. The some ways I know of are permenent marker, laser print transfers, and the Radio Shack stickers.
I had no success getting those Radio Shack stickers to stay on, and I don't recommend them.
The only way I've tryed to etch with is using a permenent marker. It may sound like it wouldn't give good results, but with good planning, patients, and a steady hand, a nice turn-out can be had.
To ensure good results with this method be sure to clean the board before hand and after etching. In both cases I used fine-grit sandpaper, soap and water, and alcohol.
I used a Sharpie to mask. When I drew the traces, I copied and pcb layout I had found online and used the IC I needed to make sure it would line up correctly. When applying the marker, make sure that there is a thick layer of ink covering the traces, or the solution will eat right through the copper underneath.
There are a couple tricks I have heard and learned with this method. One I learned is to pull the board out mid-etch, wipe the board, and go back over the traces with the marker. This will leave thicker copper tracks and more unwanted copper disolved.
Another trick is to completely mask a whole row of a DIN IC and separate the pads with a knife after etching. This will allow for wider pads for the IC and better alignment.
Follow these steps and you should quickly learn how to cheaply and easily etch with just a marker and some solution.
I plan to try the laser printer iron-on masking next. I read a review somewhere that the best paper for this is Staples photo paper. We'll see how that turns out.
Oh yeah, by the way, make sure you don't get any solution on your hands. If you do, don't eat any crackers or anything. I did, and get not get to sleep that night because I could not get the taste and smell out of my mouth.
I hope all this helped. |
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| ingrast |
You may want to check Think & Tinker for a dry resist process I use and recommend.
Select only the chapters relevant for you, there are procedures and products for through hole, multilayer and solder mask processes also.
You may substitute an ironing appliance for laminator - be ready to spoil some trials - but cut no other corners. I can routinely make .01" tracks this way after tunning carefuly the process.
Rodolfo |
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| markp |
| I use dry transfers, toner iron-ons, and sharpies to get the patterns I want. Make sure the board is very clean and oil free(no fingerprints) and the dry transfers stick fine and work well. The best method is to get some laser printer transpearancy sheets and print your pattern on them and iron the pattern onto the board, it takes practice to get the right tempuratures on the iron but its worth it! You can go over the iron-on with a sharpie if you wish. If you have very wide traces you can go over them with nail polish. When done acetone takes the polish and toner transfer off the traces. |
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| TwoSpoons |
Pulsar for the toner transfer method. Read through and you'll see that toner alone is porous, leading to pinholing. Toner reactive film is supposed to fix this. They also have a sponging technique for etching, that I've not tried.
I've had good results using toner transfer, and ammonium persulfate etchant.
Keeping your etch bath at 50C is essential, also constant agitation for even etching. |
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| jacco vermeulen |
With luck you can find a HP flatbed plotter in a dumpster.
The pens should be filled with etch resistant ink.
a PCB board can be positioned on the plotter bed, the circuit is directly written on the board by the pens. |
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| Markje |
I use those stickers. You put them on the board, then rub them on top and they stay on the PCB. Works al right with me. They dont come of or anything.
One major disadvantage, the minimum track width with the ones I use is about 1 mm (1/25 inch), which means you cant make a track between two pins of a DIL IC.
I'm looking for a nice UV light and then I want to try it tha way.
Greetz Mark |
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| ingrast |
| quote: | Originally posted by Markje
...I'm looking for a nice UV light and then I want to try it tha way.
Greetz Mark |
Get one of those inexpensive 125W mercury vapor lamp and ballast.
VERY CAREFULY break the outer envelope (draped with a piece of cloth or something) to expose the inner quartz bulb, remove with pliers the broken glass sticking from the base and you are done.
Take care to construct a box shield or something (you may even make an inexpensive aluminium parabolic reflector). Avoid staring at the bulb directly when turned on.
This is the setup I use and it works fine for boards up to 5x8" or so. With dry resist from Think & Tinker, exposures are excellent with less than 3 minutes including lamp warmup.
Rodolfo |
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| markp |
| quote: | Originally posted by ingrast
Get one of those inexpensive 125W mercury vapor lamp and ballast.
VERY CAREFULY break the outer envelope (draped with a piece of cloth or something) to expose the inner quartz bulb, remove with pliers the broken glass sticking from the base and you are done.
Take care to construct a box shield or something (you may even make an inexpensive aluminium parabolic reflector). Avoid staring at the bulb directly when turned on.
This is the setup I use and it works fine for boards up to 5x8" or so. With dry resist from Think & Tinker, exposures are excellent with less than 3 minutes including lamp warmup.
Rodolfo |
Not a great idea!
:hot: :hot:
Nothing like mercury vapor to make your day! |
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| jackinnj |
| quote: | Originally posted by markp
Not a great idea!
:hot: :hot:
Nothing like mercury vapor to make your day! |
WHATEVER YOU DO, DON'T VACUUM UP SPILLED MERCURY
mercury can even be transmitted "intra-uterine" to a fetus -- results in kidney failure, stomach lacerations, etc., etc. |
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| ingrast |
| quote: | Originally posted by markp
Not a great idea!
:hot: :hot:
Nothing like mercury vapor to make your day! |
You are not supposed to break the inner quartz bulb (which is quite tough anyway) where the mercury vapor is enclosed. As long as it is contained there is absolutely no risk.
As said, I've made several of this setups for years with no mishaps and excellent results.
Rodolfo |
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| Mike Gergen |
If you want high levels of UV just buy a blacklight for a couple bucks. Easy to run, cool temp and no safety issues.
The thought of breaking open a mercury vapor lamp is way NOT COOL. The reason that outer glass case is there is that if the HID tube breaks(and they do) the mercury and other chemicals will be contained.
That HID tube has a surface temp of over 3000 degrees Kelvin! Just touching the tube and getting oil from your fingers on the quartz is enough to create a hot spot on the tube which can lead to failure.
The same holds true for any of the HID lamps. I've been involved with them for years in lighting of aquariums, as a Facilities manager I used them for building and car park lighting, and other applications.
The thought of doing this with children or pets in the house... If they break the lamp by mistake. Lord help 'em
Mike |
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| TwoSpoons |
Blacklights are generally not short enough wavelength.
There is stuff all mercury in these lamps, you're at more risk from amalgum tooth fillings, or eating Tuna!
The quartz tube cannot possibly be at 3000K, it would be a runny puddle at that temp :smash: . Quartz softens around 1600 C.
One of my work mates simply uses bright sunshine - it behave like a point source, giving better shadow edges than diffuse light from a mercury lamp.
You really ought to give the toner method a crack. With a 1200dpi laser printer I can produce boards with 10 mil track / clearance, though 15 mil is easier. |
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| Elso Kwak |
Guys,
There are special UV TL-tubes available from Philips or Osram for exposing presensitized PCBs. DO NOT BREAK OPEN Mercury lights. DO NOT even think of bringing these in your home!
Mercury poisoning is very nasty and takes a VERY long time to recover, if ever.
Part number:
Philips TL8W/05 Part#530697 on www.conrad.de
Exposure time about 1 minute and 25 seconds.
:att'n:
:att'n:
:att'n: |
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| AuroraB |
The recipee for hydrocloric/peroxide etchant is 2 parts water, 1part 40% HCl and 1 part H2O2 40%. This gives a reasonably fast but well controlled etchant. Mix cannot be stored!
Releases clorine gas, so use only in well ventilated area! |
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| AuroraB |
That recipee is from the old reference handbook for radio engineers,- along with alot of others....
I have used it often, when in a hurry and our machines are down...
No problem at all, if you know the hazards...
For the 40% peroxide,- here in Norway 35% is standard strength at the local pharmacy....I just add a small dash more than the 1 part...
And I do use sodium persulphate in my machines at work...
Ferric chloride makes nasty stains on my clothes,- the persulphate just makes nice holes....;) |
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| blu_line |
I bought the H2O2 (30%) but have not found a source for the HCl.
So had no possibility to try it yet.
| quote: | What?, do I read that right 40% hydrogen peroxide???
Come on, leave that stuff in the laboratory. Use ferrichloride or Ammonium- or sodiumpersulfate.
Are you tired of life?
|
Conrad is pulling away more and more chemicals from their catalogue. And this mixture of HCl and H2O2 is cheaper, gives better results and will be available long after conrad and others have stopped supplying etchants.
And why buying those expensive TL-tubes ?
Go to a bazaar or 2nd hand shop and you buy a sun-tanner thingy for 10-15 euro/dollar.
grtz
Simon |
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| Elso Kwak |
Hi Simon,
The Seno-Feinätzkristall can still be obtained from Conrad (part# 529427) "Sofort verfügbar". The solution can be kept for months.
The UV-tube is Euro 10.50.
:idea: |
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| TwoSpoons |
30% HCl is often sold as 'Spirit of Salts' in hardware stores.
30% H2O2 is sold as 'Baquacil Shock', part of the Baquacil pool treatment range from ICI. |
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| AuroraB |
| HCl or "Salzsäure" is sold in paint shops and building shops here in Norway, - it is used to clean brick work and other kinds maisonry.... I don't know about Holland....?? |
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| jackinnj |
over here "Muriatic Acid" -- HCL -- can be bought at most hardware stores -- just as you state for cleaning brick and stonework.
I use H2O2 from the pharmacy -- straight, then add HCL -- works without heating.
FeCl stains everything and is not good with stainless steel sinks.
whichever etchant you use, make sure to dilute the effluent with A LOT OF WATER --
and of course ACID to WATER and not the reverse.
jack |
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| blu_line |
What percentages you use ?
The pharmacists here have =<10% only !
Will that be enough ?
grtz
Simon |
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| blu_line |
| quote: | | The Seno-Feinätzkristall can still be obtained from Conrad (part# 529427) "Sofort verfügbar". The solution can be kept for months. |
I know ! I needed for my "etching machine" about 5 liters of that stuff. Separate bags would be quite expensive.
They had a larger container (2kg) in theit catalog also , but due to new regulations in the "voedsel en waren wet", it was not allowed to carry this item anymore because the manual was in german.
| quote: | | The UV-tube is Euro 10.50. |
Per tube ?
Or per set with loads and starters ?
grtz
Simon |
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| Elso Kwak |
| quote: | Originally posted by blu_line
I know ! I needed for my "etching machine" about 5 liters of that stuff. Separate bags would be quite expensive.
They had a larger container (2kg) in theit catalog also , but due to new regulations in the "voedsel en waren wet", it was not allowed to carry this item anymore because the manual was in german.
Per tube ?
Or per set with loads and starters ?
grtz
Simon |
Hi Simon, yes the Euro 10.50 is per tube.
Farnell has Fine Etch Crystals bags making 5l of solution. They sell in quantities of 1+/10+/25+/50+. Partnumber 3205022. Price Euro 37.55 ex BTW for the 1+ group.
Display Elektronika shops or "De Onderdelenspecialist" have 1.1kg bags of fine etch crystal for Euro 38.68 each
What are you planning? I feel your etching machine is way oversized.
:cool: |
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| jacco vermeulen |
Mine does 2 gallons, every refill takes 4 lbs of NatriumPerSulfate.
That stuff works just fine, i see no need for using Seno material.
Conrad markets the kristals under #551970/#152014.
Anything other than that nasty ferro stuff should be just fine i think, seems that the majority is still using clothing dye. |
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| Elso Kwak |
| quote: | Originally posted by jacco vermeulen
Mine does 2 gallons, every refill takes 4 lbs of NatriumPerSulfate.
That stuff works just fine, i see no need for using Seno material.
Conrad markets the kristals under #551970/#152014.
Anything other than that nasty ferro stuff should be just fine i think, seems that the majority is still using clothing dye. |
Jacco,
It's sodiumpersulfate in English...
# 152014 did not yield any result on www.conrad.nl
2kg of sodiumpersulfate for Euro 18.13 is a good price! (part# 551970)
Thanks for the hint.
One bag of Seno stuff, weighing 238g is about Euro 8.
;) |
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| jacco vermeulen |
#152014 is the number on the container, the other is the Conrad ordering code.
Thank you for correcting me, Elso, i mentioned the Natrium supposing Conrad lists it as such.
Could be that Seno's may be fractionally better.
As the fish bassin in my residence, referred to as an etching tank by the manufacturer, requires loads of the stuff sodiumpersulfate works for me.
I thought of acquiring a smaller tank for ocassional small PCB's
(mine takes 20" boards), Seno still seems pretty expensive.
I started my etching with a plastic tray on the kitchen sink with Seno crystals and the Seno PCB manufacturing manual.
Switching to lower priced etching substances seemed to work with equal results.
The horrible brown iron stuff i bought once, the odor turned me off !
However, i am interesting in reading any advantages of Seno compared to other brands. |
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| Markje |
In Holland you can buy HCl at the pharmacy (de apotheek dus), Hydrogenchloride in low concetrations is practically harmless. On an open wound it feels like pooring cocacola on it, it burns, but nothing else. If you accidently swallow it, eat a piece of old fashioned handsoap. Not the liquid stuff most people use today, but the soap you used to see ten years ago.
Greetz Mark |
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| thomas997 |
Just tried some Ferric Chloride last night.
Only took about 10mins to finish. It helps to rub the copper with something while its etching, the board may look untouched, but you rub it and then you see most of the copper has dissolved.
Used the microwave very carefully to get it to 50C. Only needed 2 heating sessions total (about 20s each). |
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| Prune |
| HYDROGEN PEROXIDE IS A CARCINOGEN!!!!! |
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| Netlist |
Appreciated Prune but both terms actually mean nothing to me.
According to the big bold red text both look very dangerous.
Please elaborate a bit. What are we dealing with?
/Hugo :) |
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| Prune |
Huh?
Hydrogen peroxide is a commonly used antiseptic (when diluted with water). It's water with an extra oxygen atom -- H2O2 -- it is useful for being a strong oxidizer.
Carcinogen means it causes cancer, it's a very common English word. jackinnj posted (second post in this thread) that a diluted mix of hydcrochloric acid and hydrogen peroxide can be used to quickly etch copper for PCB making, so I thought it was irresponsible not to post a warning that the latter can cause cancer. |
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| SY |
:att'n: All this stuff is so toxic and so corrosive that cancer is the least of your worries.
Be aware that the blue color one sees is a copper salt which is also quite toxic. And VERY unfriendly to the environment. |
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| Prune |
| It's been a while since I took chemistry, but my guess is the blue is copper sulfate. Good stuff to kill off the algae in your aquarium (but will also hurt some aquarium plants and invertebrates like snails and shrimp, though fish should be fine if concentration is limited, but that's difficult to calculate as hard water inactivates much of the copper). I've also used it mixed with lime to make Bordeaux mixture, which was somewhat effective for dealing with the inevitable (in wet Vancouver and using non-resistant heirloom varieties) blight on my tomato plants. Though in the end I still had to use chlorothalonil (so much for avoiding nasy chemicals). And of course, this is a good demo of a totally off-topic post :p |
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| richie00boy |
All these different chemicals and warnings without quoting previous posts are getting me confused. Can somebody please confirm if these two are nasty and if so which is the LEAST nasty to me for home etching:
1. sodium persulphate
2. ferric chloride
Cheers |
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| jackinnj |
HYDROGEN PEROXIDE IS NOT A HUMAN CARCINOGEN AS DETERMINED BY THE INTERNATIONAL AGENCY FOR CANCER RESEARCH!!!!!
if it were you wouldn't see all those blondes in Hollywood. |
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| Prune |
| It is a known animal carcinogen (http://www.bu.edu/es/labsafety/ESMS...ml#anchor891201). Forget not, humans are animals. However, there are not many cases of ingesting it in humans, and thus the lack of cancer in humans caused by it, which is why the beurocracy cannot assert it is a human carcinogen (but can be classified as a probable one, due to the animal studies). Maybe you can be the first human test subject. I'll even send you a few bottles at no charge. |
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| jackinnj |
peanut butter is also a carcinogen --
you are unnecessarily alarmist. |
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| SY |
Chloride, not sulfate. There's no source of the sulfate anion.
richie, persulfate is nastier than FeCl3 before use at similar concentrations. But it's sort of moot, like asking what's a worse shock from a big power supply, 3000V or 3500V? |
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| markp |
| In most large cities the AIR is a carcinogen and you are exposed to it much more than you would be using any of these chemicals. Sure, don't eat it or bathe in it but don't be too paranoid, it will cause stress related problems far worse than a brief exposure to this stuff. |
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| richie00boy |
| Thanks SY. I was concerned about vapour and splashes on my skin, but it seems maybe I'm OK as I'm quite careful with the raw powder. Although the Sod Per I have is quite fine and does create a little dust that can be breathed in, when measuring out :( |
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| RetroAudio |
| I think the largest worry with any of this stuff is to not inhale much during etching,..or any at all if you can help it. My setup involves an overhead stove fan and an industrial face mask air filter,..(it reminds me of "The Wall " with those gas masks), with my head NOT directly over the etchant tank. It seems to help versus not having the above. At any rate, I think everyone in here is bright enough not to swallow or snort such chemicals, right ? Also, rubber gloves are nice. :smash: |
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| SY |
| You want a good dust mask when handling persulfate powder. Bad, bad stuff to get in your lungs. Rubber gloves, and I mean REAL heavy-duty industrial gloves are not a nice thing, they're a MANDATORY thing. |
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| jackinnj |
| quote: | Originally posted by SY
You want a good dust mask when handling persulfate powder. Bad, bad stuff to get in your lungs. Rubber gloves, and I mean REAL heavy-duty industrial gloves are not a nice thing, they're a MANDATORY thing. |
Neoprene -- you can get them via the web http://www.magidglove.com/neopreneg...7A-C3E1C24C7FBA |
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| Prune |
| SY, I was thinking of sulfuric acid instead of hydrochloric. It can also be mixed with peroxide to etch copper (actually even aerated vinegar etches copper, as it became apparent to me after I used vinegar to clean my Mauviel cookware of the oxides several times -- there's always some copper removed if besides acid there's oxygen present -- gotta use professional copper tarnish remover). |
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| richie00boy |
| quote: | Originally posted by SY
You want a good dust mask when handling persulfate powder. Bad, bad stuff to get in your lungs. Rubber gloves, and I mean REAL heavy-duty industrial gloves are not a nice thing, they're a MANDATORY thing. |
Bit frightened now :(
I suppose if anything was going to happen I'd just have been ill at the time the Sod Per dust was floating about? Or is it a delayed thing like asbestos? |
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| SY |
You've got less than a week to live. And you'll be impotent for the last 6 days of it.
No, seriously, the damage you would get is immediate and on the order of a burn. You lucked out, but don't press your luck the next time, wear a mask. A good, healthy fear of corrosive chemicals is a good thing, just like fear of high voltages. |
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| richie00boy |
| Thanks again SY. I have one of those white dustmasks for home and car DIY. I will wear that next time. |
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| AuroraB |
GAsoline is a carcinogene, mineral oils might be, and so on, and so on,- forever!
Life is quite dangerous, you know--- you might even die!
Main point in this,-- all of the chemicals used mentioned here are dangerous,- if not handled and used properly!
So is actually quite a lot of your "domestic" chemicals, as several types of detergents, cleaners, oils etc.etc.
Our in-frequent hobby use for making PCBs are quite harmless,-
if done properly! Just take care, - and be happy!!! |
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| TwoSpoons |
I use ammonium persulphate regularly. I get it on my hands regularly. It does nothing to my skin. Absolutely nothing. You wouldn't catch me bathing in it, but I really think the level of paranoia I'm seeing here is quite unjustified.
Personally I think warnings like 'Probable carcinogen' are mostly just 'ars* covering' prompted by the American legal system.
With any of these chemicals, so long as one exercises 'reasonable' care ( i.e. don't drink it, wash hands and utensils, keep away from kids) you should be fine. The full-on chemical warfare suit is unnecessary.
Honestly, theres far more toxic sh*t put in the food you eat every day (aspartame is particularly nasty). |
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| Prune |
| quote: | Originally posted by AuroraB
you might even die! |
Speak for yourself. |
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| SY |
TwoSpoons, I don't often say this, but... you have no idea what you're talking about. I don't usually do the flaunting credentials thing, but I did manage to get a chemistry degree and teach lab courses at the university level for 10 years, not to mention 20 years in the electronics materials business. It is absolutely UNACCEPTABLE to recommend that people not bother with basic safety equipment. If someone tells you, "Oh, I never bother with a guard or push-blocks when I use my power saw and I've done OK," you know you're dealing with someone whose nickname in the future is going to be "Stumpy." Likewise for the use of these chemicals.
:att'n: These are chemicals of known, proven, severe corrosiveness and toxicity. They should ONLY be handled using the proper safety equipment: goggles, gloves, and ventilation. |
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| Prune |
| quote: | Originally posted by SY
If someone tells you, "Oh, I never bother with a guard or push-blocks when I use my power saw and I've done OK," you know you're dealing with someone whose nickname in the future is going to be "Stumpy." |
I'm fairly certain that Peter Daniel posted somewhere around these forums that he doesn't use guards when working metal, as with his experience they are an impediment. |
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| jackinnj |
| quote: | Originally posted by SY
TwoSpoons, I don't often say this, but... you have no idea what you're talking about. I don't usually do the flaunting credentials thing, but I did manage to get a chemistry degree and teach lab courses at the university level for 10 years, not to mention 20 years in the electronics materials business. It is absolutely UNACCEPTABLE to recommend that people not bother with basic safety equipment. If someone tells you, "Oh, I never bother with a guard or push-blocks when I use my power saw and I've done OK," you know you're dealing with someone whose nickname in the future is going to be "Stumpy." Likewise for the use of these chemicals.
:att'n: These are chemicals of known, proven, severe corrosiveness and toxicity. They should ONLY be handled using the proper safety equipment: goggles, gloves, and ventilation. |
All it takes is seeing one industrial accident.
Gloves, safety goggles, face mask when using a cut-off saw...there should be a thread devoted to safety.
I Share the perspective on chemistry, having gotten my undergrad degree there -- and having lost the sense of smell for a few months because I didn't do something under the hood. |
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| SY |
| quote: | Originally posted by Prune
I'm fairly certain that Peter Daniel posted somewhere around these forums that he doesn't use guards when working metal, as with his experience they are an impediment. |
I claim no expertise in metal-working. In fact, I'm downright ignorant. But I did have a shop teacher in high school who was missing half his fingers. We were merciless; we'd hold up out hands and yell "Hey, Mr. Skidmore, slap me two-and-a-half!" Nonetheless... it was an instructive example.
My favorite quote was from a text on formulation regarding the use of three roll mills for pigment dispersion: "Operators of three roll mills tend to have N fingers, where N < 10." |
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| markp |
| quote: | Originally posted by SY
I claim no expertise in metal-working. In fact, I'm downright ignorant. But I did have a shop teacher in high school who was missing half his fingers. We were merciless; we'd hold up out hands and yell "Hey, Mr. Skidmore, slap me two-and-a-half!" Nonetheless... it was an instructive example.
My favorite quote was from a text on formulation regarding the use of three roll mills for pigment dispersion: "Operators of three roll mills tend to have N fingers, where N < 10." |
The ratio is one half finger for every 7 years worked! |
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| TwoSpoons |
Reread my post. I'm in favour of reasonable precautions. I just object to the sort of hysteria that leads people to post words like ' probable carcinogen' in giant red letters.
Ammonium persulphate doesn't induce me to run screaming off to the emergency clinic for a little splash on the hand. The 68% nitric acid I have in my lab does, however - that one I do treat with real care (gloves, goggles, mask, caution). As with the other genuinely toxic nasties I possess.
Be realistic - pcb etchants are available off-the-shelf to Joe Anybody, and no manufacturer would risk their business by selling something insanely dangerous to the public. Except maybe the tobacco industry.
Again: reasonable care! |
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| Prune |
| BWAHAHAHAHA! It was a joke, geez! It's only a carcinogen if you swallow it. I use is on cuts all the time as it doesn't sting like alcohol. I've spilt HF (aq) on my hands and I didn't run screaming, either. |
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| jackinnj |
| quote: | Originally posted by Prune
BWAHAHAHAHA! It was a joke, geez! It's only a carcinogen if you swallow it. I use is on cuts all the time as it doesn't sting like alcohol. I've spilt HF (aq) on my hands and I didn't run screaming, either. |
about ten years ago a New York City garbageman was killed because some jerk disposed of HF incorrectly -- this is about as polar an acid as you can get. |
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| SY |
HF is funny stuff- a surprisingly low pKa. Not a "strong acid" by definition, but highly toxic and corrosive. Eats through glass.
I've said it in a few other posts, but it bears repeating- besides your own safety, there's the safety of others and the environment to consider when you dispose of these solutions. |
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| Prune |
Best thing about HF is absorbtion through the skin. I think there are several cases of death.
There was some kind of thermite that gives off F (gas), but I can't remember what the components were (I never tried to make it, I'm not that crazy). |
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| Prune |
| Hmm. It's been over 12 hours and the precipitate is barely starting to form. Maybe it's the weak 3% peroxide I'm using that's making this so slow... Not very practical. But without accessible sources of nitric acid, one is pretty limited in what fun things can be made. :hot: |
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| jacco vermeulen |
| You dont sound like a happy camper, Prune |
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| Prune |
I'm not sure what you mean by 'camper' (English is not my first language, so you'll have to excuse me).
This has nothing to do with happiness or angryness -- don't think you can make assumptions of how I intend to use this. It's purely for entertainment. The same thing that drives me to DIY audio is behind most other things I do. In any case, I only made a few mL. (CSIS, eat my shorts! :D ) |
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| dherr555 |
| I have seen alot of stupid things in my life.But why do people think wearing rubber gloves is such a pain.Its a simple thing to do to prevent injury.Now what was good etchent besides ferric chloride.Or does it work better warmer. |
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| richie00boy |
| Using cold FeCl is just a waste of time IMO. It should be about 40 degrees Centigrade. |
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| Tweeker |
Hydrofluoric acid (HF) is extraordinaly dangerous and insidious. A solution that wont cause immediate skin burns may over the course of hours migrate through the skin and muscle to the bones where the fluoride ions start binding with calcium causing a world of hurt.
Sure hydrogen peroxide is carcinogenic, its all a question of dose. Dont drink the stuff, its hard on your liver. Dihydrogen monoxide can kill you given a large enough dose. It can be especially bad by inhalation... |
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| SY |
Dihydrogen monoxide (also known as hydric acid) is a particulaly insidious chemical. And governments are doing nothing about it.
www.dhmo.org blows the lid off this scandal. |
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| SteveA |
Prune-
You stated that it was some time ago that you took your chemistry classes. Hydrogen peroxide is NOT a carcinogen. It wasn't when you took your chemistry classes. It wasn't when I took my chemistry classes. It won't be when our grandchildren take their chemistry classes.
SteveA |
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| SteveA |
FWIW, I much prefer ammonium persulfate to ferric chloride (and so does my wife).
SteveA |
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| Prune |
| SteveA, I posted a reference, whereas you are talking out of your you know what. |
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| Tweeker |
Heres a link to an actual paper using it:
http://carcin.oupjournals.org/cgi/content/full/20/3/485
| quote: | | Chronic infection/inflammation is implicated in the pathogenesis of several forms of cancer, including hepatoma. It is well known that during inflammation, cells release reactive oxygen species, particularly H2O2. However, the role of H2O2 in the development of cancer and the underlying mechanisms are not well defined at this moment. It was our intention to test the hypothesis that H2O2 is involved in the enhancement of liver carcinogenesis and to investigate the possible mechanisms responsible for this process. |
The most common source of this liver inflamation in people is ethanol.
Necrosis is going to be a vastly greater issue in any significant direct exposure to peroxide, you wont get cancer because the cells are all dead. It destroys the viability of the cell before it can get to genetic material, unlike in the above example where the peroxide is produced inside the cell.
If your going to worry about carcinogens, stay away from smokers, dont use a gasoline lawn mower, dont eat charred meat, stay away from all new plastic and its free monomers. Avoid new car smell! All of these are greater cancer hazards than the normal careful usage of hydrogen peroxide. |
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| SteveA |
Prune-
I am talking "out of" my background, which, like Sy's is chemistry. While I have a considerable lack of knowledge in electronics (and enjoy learning from the members here), my doctorate is in chemistry. So I'll let you decide from where I am speaking.
SteveA |
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| Prune |
Your degree is irrelevant, when there is peer reviewed evidence, and for example in SY's link one reads:| quote: | | A3. Confirmed animal carcinogen with unknown relevance to humans. |
Let me remind you that humans are animals. One thing is clear about your degree -- it's not in biology.
This is not the board to arrogantly brag about your academic titles (or how honest the methods of obtaining them were). |
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| SteveA |
Prune-
And yours is clearly neither chemistry nor biology. In the excerpt you selected humans were not the animals for which the carcinogenic activity was confirmed. As you point out, I am not a biologist, but I would guess most biologists would agree that all animals are not the same (the part of the quote about the relevance to humans would seem to be consistent with that assumption)
My apologies to the members if mentioning my educational background was done in an arrogant or offensive manner. Back to etching circuit boards.
SteveA |
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| Prune |
| Nah, I'm just busting your chops. :p |
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