Quicksilver

[John HaineParticipant @johnhaine32865]

The head of science at my school in the 60s was a crusty old gent who had equipped the physics labs after the war with surplus meters etc – you haven't lived until you've used an altimeter to balance a Wheatstone Bridge! Amongst other things he bought a crate of bottles of mercury which lived in the cellar – I think they had got through a couple of bottles by 1968, where it went who knows!

Regarding mercury arc rectifiers, these don't emit x-rays. In the machines lab at uni there was a test setup with a 3-phase one in a big steel cabinet where you could look at the arc through a strobe disc, if you got the speed right you could see the arc stepping from electrode to electrode as the phases changed. The technician used to warn us against opening the door because of the UV, but the machines lecturer encouraged it, pointing out accurately that the glass stopped nearly all the UV. Great fun.

[Roger HartParticipant @rogerhart88496]

Just checked my (UK) local council waste disposal website and it says that the usual dump site takes mercury and other chemical stuff. Seems pretty sensible because I guess no-one wants that sort of stuff chucked in the nearest hedge or pond.

Rather leaving themselves open though, I suspect the denizens of this site might know of many nasty substances lurking in attics and basements.

Way back telephone exchanges used mercury arc octopuses. Lots of fun when one broke and about 1 pint of Hg spilled on the floor….. More fun when someone went to change one of them new fangled germanium rectifiers and diligently turned off the mains but forgot to isolate the battery. Much very quick movement…..

[Cornish JackParticipant @cornishjack]

Samsaranda – mixing mercury and aircraft was always tricky ! The Britannia you mentioned was a complete write-off – no possible way of tracing all the little globules. Can't remember which, but I seem to remember that at least one of my operational types had mercury triggered crash switches. Post retirement, I worked part-time in a watch and clock shop for a friend. He informed me one morning that he had dropped and broken a stick barometer the previous evening and had swept the resultant mess into the rubbish bin. I did an online search and showed him the results – he was suitably impressed!!

rgds

Bill

[Ian S CParticipant @iansc]

I remember one day in school general science class one of the girl s was most upset, her gold signet ring had turned silver, she had had a small amount of mercury rolling around on the palm of her hand. I also rem,ember about a similar time when I would open the little mercury button cells after they went flat, and squeeze out the mercury, I had a little jar with about 1/2 an inch of mercury from a number of sources, don't know where that went.

When I was nursing, it was infrequent, but on occasions someone would drop a rack of clinical thermometers (usually 30), back in the 1970s it was just a case of sweeping up as much as possible and putting it in the dangerous goods rubbish (all those little bits of glass).

Ian S C

[John HaineParticipant @johnhaine32865]

At least 1 747 has been scrapped after mercury contamination.

[Neil WyattModerator @neilwyatt]

There's a condition called Minamata disease.

It affected people who ate fish caught from areas of the sea around Japan contaminated by mercury pollution.

But I handled mercury as a kid so it can't be dangerous…

Neil

P.S. One chemistry teacher needed to dispose of some sodium that was considered too large to be safe for school use (even in the 70's). He threw it in the school pond and legged it Apparently there was a large ball of flame and the pond was emptied.

P.P.S. I spent a quarter of an hour being irrigated after someone else put a small piece of sodium in a dry sink…

[SillyOldDufferModerator @sillyoldduffer]

Before chucking it away know that a ton of mercury at wholesale prices would set you back nearly $68000. Iron is less than $100 / ton. Mercury may not be in the same league as Gold, but still…

PS Mercury metal isn't dangerous, but the vapour is.  A few individuals are much more sensitive than most of us which is why schoolkids don't play with it any more.  Although the risk is low, most headteachers think one 999 call is too many. 

Most chemical compounds containing Mercury are poisonous and quite a few are off-the-scale deadly.  The lady mentioned earlier was a Professor of Toxicology, fully qualified and equipped to handle the chemical that killed her.  She was poisoned through an intact rubber glove.

Dave

 

Edited By SillyOldDuffer on 04/06/2019 16:15:34

[Ian Johnson 1Participant @ianjohnson1]

Posted by Fowlers Fury on 04/06/2019 12:33:48:

In terms of huge volumes of Hg, the Castner-Kelner process for producing chlorine and caustic soda by the electrolysis of brine is worth a mention. The old ICI "cell rooms" in Cheshire were incredible; in each, the amount of Hg could be around 100 tons, the current required upto 200,000 amps at 200V. The gap between the electrodes and the Hg surface was very critical for efficiency – too close and imagine the result !
Hazards of Hg were well known in the 60s and workers were routinely monitored. Mercury vapour was released along with the hydrogen from electrolysis and traps were needed to recover the liquid Hg. When the diaphragm process began to replace the mercury process from the mid 70s those huge volumes of Hg would have had to have been disposed of – maybe sold?

Crikey! That's a blast from the past! I was a fitter in those cell rooms, we regularly had 'piss tests' to monitor our Hg levels. Mercury seemed to be everywhere! When we 'hogged' the cell base plate we had to run the Mercury pumps to check the flow was straight down the middle of the cell for peak efficiency, it was a really beautiful sight to see a river of mercury shimmering down the base plate. The main cell rooms were 'J' 'K' and 'L' units. J and K ran at 200,000 amps and L unit ran at 400,000 amps.

The other big issue apart from Mercury was the powerful magnetism, which played havoc with steel toe capped boots!

[SamsarandaParticipant @samsaranda]

Bill, later in my career in the Air Force I was working as an NDT technician at Brize Norton and a VC 10 arrived back from a casualty evacuation and it transpired that one of the nursing staff on board had dropped and smashed a mercury thermometer. As the easiest way to detect mercury was by x-ray, the mercury being rather dense shows up brilliantly against light alloy structures; the duty engineering officer called us down to the aircraft and decided that we were going to x-ray the floor area where the thermometer had been broken. We asked if any of the mercury had been retrieved and it was pointed out that approx half of the contents had been retrieved using a mercury retrieval kit which meant that there was an amount the size of a 2 – 3 mm size ball still missing. The engineering officer was insistent that we had to x-ray to account for the missing amount, he had mapped out an area of about 5 square metres of floor space as the area of interest. The first task was to check for access under the floor to place our x-ray films, we went into the underfloor space, it was the electronics and navigation equipment bay and was crammed to the ceiling with equipment, we made our way back up to the main cabin and explained the situation to the duty engineer, he insisted that it had to be done so we said we’ll give us a call when you have removed all the equipment under the floor so that we can place film, we then left the aircraft and heard no more from him so I can only assume that the aircraft was deemed fit to fly with the tiny amount of mercury still rolling around, to my knowledge the aircraft continued to fly like this until it was phased out of service with all the other VC 10’s some 30 years later.

Dave W

[ronan walshParticipant @ronanwalsh98054]

Posted by Kiwi Bloke 1 on 04/06/2019 10:23:12:

SOD; no I haven't forgotten. We are straying off the topic, however, the deranged individual you mention is best forgotten, I think. He was, to the best of my knowledge, not a bureaucrat, and it was about them that I being rude. Since you apparently take an interest in the goings-on in NZ, you probably know that a major re-write of the Arms Act was passed within a week of the atrocity. Further legislation is promised. There was no reasonable time allowed for public submissions, nor sensible parliamentry debate. The revised legislation contains a number of 'Henry VIII' clauses. These are dangerous and I would have thought incompetent in law.

74A Order in Council relating to definitions of prohibited firearm, prohibited magazine, and prohibited ammunition

The Governor-General may, by Order in Council made on the recommendation of the Minister,—

(a) amend or replace the description in section 2A of a semi-automatic firearm (except a pistol) or pump action shotgun that is a prohibited firearm:

(b) amend or replace the description in section 2B of a magazine that is a prohibited magazine:

(c) declare any semi-automatic firearm (except a pistol) or pump-action shotgun of a stated name or description to be a prohibited firearm for the purposes of this Act:

(d) declare any magazine of a stated name or description to be a prohibited magazine for the purposes of this Act:

(e) declare any ammunition to be prohibited ammunition for the purposes of this Act.

In other words, the government can re-define various terms as it thinks fit, when it thinks fit. These 'catch-all' clauses allow for any, or all firearms or ammunition to be declared illegal, on a whim. This is not a reasonable way to write legislation. The bureaucrats responsible are dangerous: a danger to reason and democracy and are no longer acting as servants of the public.

Exactly the same thing in Ireland. The relevant minister can issue an S.I, a statutory instrument, which is basically an amendment to the act, without consulting anyone. Democracy is unfashionable currently, especially with institutions like the Eu. Which as we have seen in the past few, leaned on Switzerland, who are not even a member of the eu, to amend their historically liberal gun laws.

[ronan walshParticipant @ronanwalsh98054]

Didn't W.G Armstrong use mercury in his lighting system In his country pile, Cragside ? The first house in the world to have electric lighting ?

[Roderick JenkinsParticipant @roderickjenkins93242]

High vacuum diffusion pumps used to use large volumes of mercury. There were regular stories ( all apocryphal I'm sure ) about people trying to steal some from our establishment and being caught by security on the exit gate. They usually involved a push bike frame being filled with mercury and then being dropped and being too heavy to pick up or the bike falling apart because the mercury had dissolved the spelter joining the lugs to the tubes.

Rod

[Colin HeseltineParticipant @colinheseltine48622]

This is an interesting thread. I remember playing with mercury as a kid. I had obtained a small bottle of it from somewhere. Use to run it round palm of hand and across desks etc. I lost it somewhere in my parents house. I've just found an old Twaddell's Hydrometer No. 1 which has a glass bulb of mercury in the bottom. I think I've had it lying around for at least 50 years. And the more I think of it somewhere I have some glass tilt switches with mercury in them.

Colin

[Nick Clarke 3Participant @nickclarke3]

In one school I worked at during the last 30 years or so (genuinely can't remember which) they still had mercury barometer troughs in the physics lab.

Imagine a porcelain dish about 4" long and 3/4" wide and the same tall except one end of the trough widened out to be circular – about 1" diameter – sort of a keyhole shape in plan view or a midget version of one of those baths you can have a shower in.

When I enquired what this strange dish was used for it was explained that you filled it half full with mercury, filled up a glass tube with one end sealed right to the top with mercury, put your finger over the end of the tube, inverted it an placed the tube under the surface in the dish in the circular end before removing your finger, leaving a basic barometer. The trough was shaped to accommodate your finger that could then be removed and the tube supported in a clamp stand.

I never had the courage to demonstrate it – but no doubt I would have been allowed to do so!

The best thing was that there were a class set of these things – Imagine how much mercury would have been needed, how much it would cost and even with a well organised class how much would end up on the floor.

[old martParticipant @oldmart]

Organic compounds of mercury are extremely toxic, methyl mercury that was the cause of the Minimata disaster.

I was told by a doctor that the danger from the old style clinical thermometers was from the broken glass if the patient bit it. The mercury would pass harmlessly through the body before it had time to break down into something easily assimilated.

I had a few panicky minutes when I blew a mercury manometer over an aircraft oxygen regulator that I was testing. Fortunately for me, it was the anodising that protected the aluminium regulator.

We kept mercury in cast iron pots or polypropylene containers.

[MeunierParticipant @meunier]

It may be an apocryphal story but was informed that the low hrs E.E Lightning in RAF Hendon museum in '70s had been retired due to mercury spillage in cockpit.
DaveD

[Clive HartlandParticipant @clivehartland94829]

Just one point of interest is that Mercury is cleaned with Nitric acid, Swilled around and put through a Chamio leather to filter it. When sitting in the bowls under Barometer tubes it does get dirty.

Edited By Clive Hartland on 04/06/2019 21:20:32

[Fowlers FuryParticipant @fowlersfury]

Clive ~ we used to just squeeze the mercury through a new chamois leather to clean it. I would doubt it'd be cleaned with nitric acid, even if dilute it would form mercuric and mercurous nitrate salts.

[SillyOldDufferModerator @sillyoldduffer]

The reason Mercury writes off aircraft is that the mercury is unchanged by the reaction it causes allowing corrosion to go on forever. Given enough time, a drop of mercury could convert all the Aluminium in an air-frame into white powder. Caustic Soda attacks Aluminium far more viciously but the damage is limited because the Hydroxide is consumed, just as an electric battery goes flat and dies.

Mercury is immortal because it breaks the thin oxide layer that normally protects Aluminium from atmospheric oxygen whilst also dissolving some of the Aluminium. The aluminium in the amalgam is unprotected from air and it burns slowly on the surface of the liquid. No flame or anything dramatic, just an accelerated process similar to severe rusting in steel. The new oxide formed falls off the mercury leaving it unchanged and ready to dissolve yet more of the aircraft. Being a liquid liable to break into droplets, Mercury can go almost anywhere. As an unreactive metal itself, it can't be chemically cleaned.

The worst case is a spillage in flight – it gets splashed into every nook, cranny, hole and crack.

Dave

[Michael GilliganParticipant @michaelgilligan61133]

Posted by SillyOldDuffer on 04/06/2019 21:59:37:

The reason Mercury writes off aircraft is that the mercury is unchanged by the reaction it causes allowing corrosion to go on forever. Given enough time, a drop of mercury could convert all the Aluminium in an air-frame into white powder.

.

It also reacts very aggressively with silver halides [as in photographic film]

When I worked at Kodak, there was an absolute 'zero tolerance' ban on Mercury thermometers.

MichaelG.

[John OlsenParticipant @johnolsen79199]

You might want to check, but last I heard the way of dealing with small spillages of mercury is to scatter flowers of sulphur over the spill and mix it up well. (Flowers of sulphur is finely ground elemental sulphur) The sulphur and mercury react to form mercury sulphide, which is a stable non soluble solid. Not an organic compound so non toxic.

John

[Kiwi BlokeParticipant @kiwibloke62605]

The usual Kiwi laid-back approach to life and 'She'll be right' approach to life failed on this occasion:

**LINK**

I suppose that with a few kg of salvaged Hg you could cause a whole town to be evacuated (for ever?). If I hadn't been exposed to the nasty neurotoxin in my childhood, I suppose I might have been more intelligent, and capable of something better than posting subversive stuff in fora like this…

[Kiwi BlokeParticipant @kiwibloke62605]

John, that rings distant bells. I noticed bags of flowers of sulphur for sale in the animal care part of my local farm supply store. It seemed too good to ignore – a chance to procure something that seemed a bit 'naughty'. Apart from the obvious use (an ingredient necessary for historical attempts to blow up parliament buildings), I couldn't think of a sensible use for it, and what's it used for in/on animals? Anyway, thanks to your information, I can now deal with mercury spillages – a constant worry…

[Michael GilliganParticipant @michaelgilligan61133]

Fantastic story, Kiwi Bloke …  [almost literally]

I suspect the toxic smell was evaporated residue from the carpet cleaning products.

MichaelG.

.

Just confirmed that, in New York State at least …  "Liquid mercury vaporizes (evaporates) at room temperature causing elevated levels of mercury in indoor air. Mercury vapor is not irritating and has no odor …"

https://www.health.ny.gov/environmental/chemicals/mercury/docs/cleaning_up_a_small_mercury_spill.htm

Edited By Michael Gilligan on 04/06/2019 23:37:55

[Kiwi BlokeParticipant @kiwibloke62605]

'I suspect the toxic smell was evaporated residue from the carpet cleaning products.' – or, perhaps, panic-induced soiled underwear…

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