Sulphuric acid

Well, well Fizzy, don't exaggerate! I handled 98% sulfuric acid (in a glass bottle) when I was less than 14 years old, and I'm nearing 70 now. I don't think the small boo-boos I suffer now are reminiscences of the couple of skin burns I got from that stuff.

SpeedyBuilder, it is a long time wish of me to make a visit in one of these French shops. Unfortunately I don't know any names, and cannot raid all possible shops in a reasonable time. So I would be pleased to learn some (chain shop?) names to be able to make a direct jump. It is quite well known that all kind of interesting stuff is still available there.

Greetings, Hansrudolf

A bit off-topic but ...

Back in 1988 I had a spell in hospital in Romford, Essex. The guy in the next bed, retired by then, told me that he had worked in the big sewage treatment works at Beckton, at the end of the Great Northern Outfall sewer. He said that, at the time of the Haig acid murders, the Met Police sent through a request that the workers should keep an eye open for any false teeth or plastic handbags arriving in the sludge lagoons!

Optimistic or what?!!!

Best regards,

Swarf, Mostly!

Speedy,

Sodium chloride becoming difficult to buy in France? Are they becoming health-obsessed or do they just not like you adding seasoning to the amount the divine chef thought was appropriate?

David

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

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

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

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

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,

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

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.

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

Clive

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

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

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

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

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.

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.

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

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