Sulphuric acid

[Ian S CParticipant @iansc]

Speedy, proberbly Speleolagists/cavers, arn’t there quite a number of areas in France where there is large cave systems. Some still prefer carbide lamps underground. Ian S C

[Steve WithnellParticipant @stevewithnell34426]

Posted by MICHAEL WILLIAMS on 25/08/2012 12:09:24:

 

The men wore flat caps and gauntlets but no other protection ,

I think any Health and Safety man visiting then would simply have been dissolved .

Michael Williams .

 

I have an old electroplaters handbook,  where the remedy for cyanide salt burns is to wash the wounds with dilute sulphuric acid…I assume followed by copious amounts of fresh water!

 

Edited By Steve Withnell on 25/08/2012 13:04:17

[David LittlewoodParticipant @davidlittlewood51847]

Fizzy,

I'm with Hansrudolf on this; you are exaggerating quite a lot. H2SO4 will indeed destroy flesh, but it takes more than an "instant" to do it. If you get a small splash on your hand, you probably have 5-10 seconds to wash it off before you suffer more than superficial damage. I too was handling it from my early teens and through university and industry, and simple care meant I never had any problems with it. I even have a few litres in my workshop for pickling and plating purposes.

Fuming sulphuric acid (oleum) as mentioned by Michael above is a different story, as it is in effect SO3 (sulphur trioxide, a highly corrosive gas)) dissolved in concentrated sulphuric acid. That gives off fairly deadly fumes and has been know to overcome people exposed to it so they fall into the hellish stuff. It is used in the manufacture of H2SO4 for the simple reason that, although the latter is just formed by reaction of SO3 + H2O, if they just mix them together they get an unholy amount of dense corrosive vapour all around. It is, apparently, more controllable to dissolve the SO3 in H2SO4, than gradually mix that with the correct amount of water later. Fortunately you are unlikely to come across it in the wild (unless you are unfortunate enough to be around when a tanker full of it crashes – in which case just run like f**k).

If you are into dire warnings, then most people are not aware that strong solutions of caustic alkali (such as NaOH and KOH) are far more rapidly deadly to tissue than H2SO4. The latter, if splashed in the eye, will usually give you time to irrigate before it blinds you (but you do still need emergency medical attention!); the former can cause irreversible damage in a couple of seconds.

David

[David LittlewoodParticipant @davidlittlewood51847]

Steve,

Adding dilute sulphuric acid to cyanide salts is exactly the method they use in gas chambers to kill convicted murderers – it reacts to form HCN! Maybe it was a subtle way of finishing them off quickly.

David

[David LittlewoodParticipant @davidlittlewood51847]

Swarf,

It was indeed a few gallstones and some teeth that was the strongest evidence on which he was convicted; don't know where they found them though.

David

[AndyfParticipant @andyf]

Speedy, I go to France 3 or 4 times a year, and have noticed the variety of chemicals on sale in DIY shops. I think you may have meant to say that sodium chlorate (weedkiller, but can be used as a component of home-brew explosives) is hard to get. Sodium chloride is just common salt, and I doubt that French cooks would give that up without a fight.

Fizzy, concentrated acids were common currency in school chemistry labs when I was a lad and dinosaurs roamed the Earth. Like Versaboss, I know the precautions needed, but I do appreciate your concern. As soon as I can get my hands on some suitable bottles, I will dilute the stuff down to 20%. Though still nasty, that's not as vicious as 98%.

Andy,

[Clive HartlandParticipant @clivehartland94829]

Then there is, 'Aqua Regia', a mixture of Nitric and Hydrochloric acids which is the only thing to dissolve gold. It is a mix of 1 to 3.

In the early days of the armies SLR the lads were mixing up the breech blocks and causing , 'Head space' problems so we had to coat the breech blocks in bees wax and engrave through that to expose the steel and then etch with the Aqua regia, it was quick, like 1 1/2 minutes to create a good etch. Then wash off the acid and then remove the bees wax. The etch number to match that of the rifle.

The reason we could not engrave the blocks was because they were surface hardened and almost impervious. Previous Electro Etching had been rubbed away by cleaning.

One residual effect was that any exposed steel around immediately got a coat of red rust.

Clive

Edited By Clive Hartland on 25/08/2012 15:38:43

Edited By Clive Hartland on 25/08/2012 15:39:52

[David LittlewoodParticipant @davidlittlewood51847]

Clive,

Both nitric and hydrochloric acids give off highly corrosive fumes separately (and worse when mixed). I would not keep either in a workshop, as even in stoppered bottles it is hard to avoid enough escaping to cause problems for any ferrous (and many other) metals.

[Clive HartlandParticipant @clivehartland94829]

Interesting as they say you should not stopper the bottle as it builds up pressure and could burst the bottle.

Clive

[michael coleParticipant @michaelcole91146]

If you need to dispose of any acid try your local Boots the Chemist. Mine in Wallasey are only to please to get rid of it for me.

Mike

[David LittlewoodParticipant @davidlittlewood51847]

Clive,

Which particular nasty are you referring to? It is certainly standard practice to stopper bottles containing hydrochloric or nitric acids (well, usually plastic screw caps). Sulphuric acid gives off no fumes anyway.

David

[Clive HartlandParticipant @clivehartland94829]

Aqua Regia is the one that should not be stoppered Nigel.

I have used Aqua regia and it is quite nasty stuff and I was glad to see the end of that job. As it was left open it caused all the rusting.

Clive

[David LittlewoodParticipant @davidlittlewood51847]

Clive,

That makes sense; the two acids would react to form chlorine gas, only slightly soluble in water. Also highly corrosive and damaging to lungs – used as a poison gas in WW1 of course.

David

[JonParticipant @jon]

Got hydrochloric as well, used to use it for cleaning the aluminium prior to anodising. Some right fumes thinning it down, Jekyl and Hyde style, did a runner. That was sold in containers with screw on sealed caps. Knocked some diluted over a few times when just done an aluminium job, fizzzz. Drain cleaner is a very very diluted form.

Sulphuric at 19% you might get a little tingle up past your elbows, used to retrieve parts in the anodising.

[Raymond AndersonParticipant @raymondanderson34407]

Hi All,

Not model engineering but whilst we are on about dodgy chemicals just google

THINGS I WONT WORK WITH it is written by an industrial research chemist and I often read it if I want a laugh, Sulphuric acid is a benign chemical compared to this lot, I especially like the one titled Sand wont save you this time. about Chlorine triflouride, brilliant.

Regards,

Raymond.

[NJHParticipant @njh]

Hi Raymond

This is something frequently used, but pretty nasty, stuff too.

Don't put your finger into this to see what it is!

Regards

Norman

Edited By NJH on 26/08/2012 08:43:32

Edited By NJH on 26/08/2012 08:44:02

Edited By NJH on 26/08/2012 08:49:24

[David LittlewoodParticipant @davidlittlewood51847]

Raymond,

I really must give you my warmest thanks for pointing me to that blog. As a D Phil organic chemist it probably appealed to me more than it would the average reader, but it just had me howling with laughter for over an hour. My wife must have wondered WTF… Brought back a few memories of near misses too!

Rather annoyingly, the thing would sudddenly freeze and then (after a delay) shift to an error page after a few minutes; pressing the back button went back OK, but it made the reading a little laborious.

David

[Clive HartlandParticipant @clivehartland94829]

An interestinng use of Hydroflouric acid is the etching of the glass graticules in optical systems.

Again, good old beeswax is used to coat the glass and engraved through to the glass and then placed over the open top of the acid container. By trial and error they leave it for a certain time, then the wax is removed and the resultant etching is filled with black paint so it stands out in the focal plane.

Not many makers use this method now as they have perfected a system of coating Chromium onto the glass which makes the graticules finer and more accurate.

Clive

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, when I first started working for my last employer back in 1970 they used HF acid in industrial sand production. I never knew what part it played in the process, as I was just a young-en then, just got told not to go near that bit of kit. Luckily they discontinued it's use shortly after I started there, so never had much to do with it. However I knew then that it could not be put in glass bottles as it would just eat it's way through. They still used it in the lab in small quantities though, and about 25 years ago I asked if I could have a small amount for etching a bit of glass. They let me have some, but only on condition that I sign a well documented disclaimer that the company would not be held responsible for it's use or disposal and I had to accept and sign for some special burn cream. Apparently you can't feel it burning through your skin.

Regards Nick.

[Geoff TheasbyParticipant @geofftheasby]

Raymond,

'Things I will not work with' is wonderful! This guy can write like P G Wodehouse! My wife heard me gurgling with delight as I read it and asked after the fun. So I told her about my academic interest in explosives (Take note, Special Branch!) and my very interesting books on them, called 'The Big Bang', the 'Terrorist Explosive Sourcebook' and 'Explosives, Propellants and Pyrotechnics'.

Organic chemistry is something I never studied, but I find other people's tales of such experiences fascinating and the reasons why the Battle of Jutland was unsuccesfull is a tale in itself. (Clue: look up Picric Acid)

[Sub MandrelParticipant @submandrel]

So Dr Crippen was innocent- he just had aname that sounds guilty.

Nitrogen tri-iodide was one of the favourites when I was in school.

Student teacher makes some, filters it, and nothing happens, throws filter paper in bin as failure.

Later…

Mr Gwynne sets us all up for a 'prac' and goes into the prep room to make his own chemical brew (AKA tea).

Throws tea bag in bin.

We all here almighty bang.

Somewhat shaken Mr Gwynne comes in and , after interviewing us (and we all deny all knowledge of NI3) warns us of the dangers of Nitrogen Tri-Iodide, especially the danger that it only partly decomposes, and many people have lost fingers because they hadn't realised there could still be some left after an explosion.

Mr Gwynne leaves us to get on with our work.

Another, somewhat more modest, bang.

Mr Gwynne returns, this time with brown fingers.

Moral – if you are clever enough to identify a substance through the 'exploding teabag test', you should have the brains not to try fishing the leftovers out of the bin with your bare hands.

Neil

[Martin WParticipant @martinw]

Neil

Did you verify that Mr Gwynne's fingers were brown from the residue of an explosion or was it he lost control as a result the second explosion .

Martin

[AndyfParticipant @andyf]

NI3 was great fun when I was young, Neil. I recall going to Boots the Chemist for some iodine crystals. The pharmacist must have known why, because he asked if I needed any household ammonia to go with it.

But you could buy saltpetre and sulphur at Boots back then, and grind up some charcoal to make gunpowder as per the recipe in "Teach Yourself Chemistry". Much better than NI3 for blowing things up!

However did we survive?

Andy

PS The chemistry teacher's demonstration of the thermite reaction, having gathered us all close to his desk to observe the molten iron running out, is something else which is probably lost to today's youth.

[Sub MandrelParticipant @submandrel]

Andy,

You don't mention the chemists' suspicion when you ask for glycerine for icing and potassium permanganate for the fish at the same time

Neil

p.s. just noticed the SCAYT uses an American dictionary – no 'e' on glycerine!

[Clive HartlandParticipant @clivehartland94829]

Mentioning Glycerine brought back something that happened when I lived in Milton Keynes, the garden was overun at night with big black and brown slugs.

At that time I had to hand over my Firearms because of the Dunblane fiasco like everybody else who owned pistols.

This left me with some re-loading powder that I disposed of by sprinkling on the lawn and garden borders, next morning I had killed hundreds of these ugly slugs ! I can only think that the Nitro Glycerine in the powder had done them in. As the powder is just cellulose with an addition of Nitro Glycerine and coated with Graphite to inhibit the burning rate.

Unless anyone else has a better idea? It probably gave them a heart attack.

Clive

Edited By Clive Hartland on 27/08/2012 22:16:41

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