Sulfuric Acid Etch?

Michael J. Spangler

Michael J. Spangler

Joined
Oct 8, 2003
Messages
2,181
hey guys,

i was cleaning a drain and looking into the cleaning product i was wondering if it would work for etching? i would imagine it would need to be diluted. just seeing if this is a better way to go or not. i know i can get ferric down the street but we're all about messing around with new and hazardous stuff right?:D

here is the msds for it.

http://www2.itap.purdue.edu/msds/docs/12070.pdf

thanks for the help in advance.
 
Sulfuric is serious business. Even the fumes can burn you badly (as in, inside your nasal passages and LUNGS). I'm not going to give you any tips on working with it, because if you don't have experience with that sort of thing, you should just leave it alone. I don't recommend playing around with it. I worked in a chemical plant for a few years and we weren't even allowed to open a container of it without a full chem suit, gloves and respirator/safety goggles on. Move on down the road and get some ferric or just use vinegar. Seriously.

Sorry to be a spoil-sport but I don't want to see you get hurt.
 
I believe that I get a better etch with ferric and another added benefit over acid is that ferric fumes won't rust every tool in the shop like acid fumes have a tendancy to do. Luckily ferric to no worse as far as fumes go than most simple salts.

Gary
 
Hey what if you dilute it down to about 40% concentration? Its fairly safe to handle around there if i rember corectly. just a though

ps. i know i cant spell lol
 
Mike, I sent you an email with some viewpoints from a chemist's perspective.
 
fitzo, I'd be interested in your perspective as well. After all, I may be completely wrong. But I've seen firsthand the wounds and scars a drop of that stuff can cause in seconds. Phosphoric burns worse, but sulfuric burns right now.

Again, sorry to be a gloomy gus, and if I'm wrong I'll gladly eat my words.
 
Apparently the forum ate my earlier post when it had one of its frequent brainfarts.

Suffice it to say, sulfuric acid (battery acid) does not give off much in the way of fumes until it is quite hot. It has a very low vapor pressure compared to hydrochloric acid. Even ferric chloride will give off more hydrogen chloride gas than concentrated sulfuric will give off as acid vapor.
Liquid and mist contact are to be avoided because, as you mention, there are burn hazards to skin, clothes, eyeballs, paper, etc. Rubber gloves and either safety glasses or a face shield should provide adequate protection in this application. If there is contact, it should quickly be washed off with water then washed with soap and water.
Sulfuric acid will react slower with steel than muriatic acid or ferric chloride. Thus, longer etch times are to be expected. It is frequently used by European bladesmiths for etching Damasteel, damascus, and carbon steel.
 
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I've seen first hand what sulfuric acid will do to you... If there is something safer, go with it. The stuff is bad news.
 
You will get a similar etch at lower hazardwith Sodium Bisulfate (jeweler's pickle, or if you like buying it in larger quantities "PHDown from your hot tub or swimmingpool supplier) it is sort of a buffered sulfuric as far as the metal is concerned, but much safer to handle. I use it (in addition to pickling jewelry after soldering) for scale removal after forging, and discovery etching damascus. It makes nasty fumes when you put steel in, but not as bad as hydrogen sulfide (nazi nerve gas, and the source of rotten egg smell) that you will get with the wrong conditions with sulfuric.

-Page
 
Perhaps it would be best to just go cower in the closet and hope a meteorite doesn't break through the roof and smite you, Mike. :(
 
I've been using Muriatic (hydrochloric?) acid to remove scale... it works good, but the fumes seem to come straight out of WWI. I think I'll look for something else when my bottle is empty.
 
Some more basic info from another old chemist:

All acids are to be respected. The only way to make one safer to use is to dilute it. Vinegar is a dilution of acetic acid. Your stomach is full of diluted hydrochloric acid. Diluted acids are safer...but not safe. Proper storage and disposal are a must.

Some acids are more reactive with iron than others. The more reactive the ion is (chlorine, sulfur, etc) the more the acid eats at the steel. Steel with lots of acid resistant alloy ingredients (stainless steels) will require stronger acids and longer times.

Storing strong acids inside is an invitation to corrosion. Acids are best kept away from anything you don't want rust on. A locked and ventilated storage shed is best. Most acids can be diluted to harmless solution and dumped down the drain. Concentrated acids need a dilution of several hundred times to be safe for the drain system. Neutralization should be done only by those who understand it.

Ferric Chloride is what you get by combining iron and hydrochloric acid ( HCL). Muriatic acid is HCL. Sulphuric acid is a strong acid, but reacts with steel slower. White vinegar ( a dilution of glacial acetic acid) will etch slowly and is safer to the hands.

Acids for etching work best in dilution. Muriatic acid can be diluted about 5:1 with water and makes a much more handleable acid. Always add the acid to the water....never the other way around!
FC works better in a 3:1 to 5:1 solution. When mixing acids with water, especially dry ( powdered) acids (like FC) great heat can be created. Use a safe and proper container, sitting on the ground/floor. Add the acid slowly, and let it sit after dissolving until the container returns to room temp. Never hold a container in your hand and mix chemicals ! Mix dry FC with water on a 1#FC to 1 pint water ratio to make the stock solution. Dilute this as desired. I usually go a bit weaker, and add 5# FC to a gallon of water for my stock solution. This I dilute from 1:1 to 3:1 for use.

Stacy
 
In the interest of full disclosure, I should make it clear that I am NOT a chemist. I was just the guy that had to off-load and mix all that horrible stuff, according to directions I was given.
 
Oh since we are talking about acids
NEVER EVER PLAY WITH USE OR OR HANDLE HYDROFLOURIC ACID unless you really know what you are doing AND have calcium gluconate within easy reach. We use it as an ingredient in some of our metallographic etches at work and it is scary stuff. it goes straight through meat and attacks bone, it also attacks the calcium channels in nerve cells

-Page
 
sunshadow said:
...NEVER EVER PLAY WITH USE OR OR HANDLE HYDROFLOURIC ACID...
Click to expand...

True that. The info at work had all kinds of dire warnings about fatal liver damage and other horrible things.

Another one is nitric acid... I worked with a guy who had a NASTY scar on his forearm just from passing it over the open bung of a barrel without his gloves/jacket on.

Maybe I'm overly cautious about this sort of thing, but I strongly suggest that if it's not already in your kitchen cabinet, don't mess with it until you get some training or at least do your research. All we need is for some dingbat to mix ammonia and bleach (DON'T DO THAT!) or something, trying to find an etchant.
 
Ive used "easy off BAM" to etch in the past, it is a sulphuric based household cleaner.

Lots of things will etch, just make sure you use proper ventilation.

I found jugs of Ferric Chloride at an electronics warehouse locally, I use that to etch now.
 
wow a good ton of info there.

paul went out today and picked up a fresh bottle of ferric. which i like and have experience with.

thanks for all of the help and info guys. i just wanted to see if it was compatible with what we were doing.... but i guess you don't see much about it on the forums for a reason. i'm sure the main reason being that it doesn't work as well and the second being that its dangerous. thanks again for the help guys.

i'll stick to my friendly ferric.
 
Withput trying to hijack the thread, a question for you chemists: I want to make some NitAl. I have the nitric acid, which I have a really healthy respect for (in HS I spilled some and lost the front of my pants, jacket and shirt. Fortunately I didn't lose any of me) and alcohol, but need advice on what to store it in.

Also, does 5% or 10% make a better damascus etch?

Any advice is appreciated.

Gene
 
Gene, I'm sorry I'm not going to be much help; it's been since 1972 since I've used NitAl for etching metals. Thinking about it, I seem to remember we made it fresh daily in the lab and chucked it at night. If you store it, use a glass bottle rather than plastic.
Read this Wikipedia article. It is good info. I would stick to using methanol (wood alcohol) if you can find it. DON'T try it with acetone.
You might get good input on best etching concentration and further advice e-mailing Kevin Cashen. He uses it to etch metallographic samples. cashenblades.com
 
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