Mercury/Aluminium Problems

One of the first brand new chinooks had a thermometer dropped inside it ( we used to use them for taking the OAT at altitude in setting up the engines….. ) it was down for a week or so for it all to be removed, thankfully the corrosion proofing stopped any problems with contact, but we had the whole floor out after decontaminating that.

We also suffered corrosion on some of the new Chinooks as they were delivered during the winter months……. turned out the crews ferrying them to the docks from the factory would take a car in the back, these in winter had frozen snow with road salt in it on the undersides, this would melt in flight and and then sit in the cabin on the voyage to the UK quietly festering, once the floor came up on the first big inspection the problem was found.

Where did the mercury come from in this case of XM170?

According to UKserials website, the mercury contamination occurred during build – XM170 was damaged in a heavy landing. Subsequent investigation led to discovery of corrosion.

What, this one?

Mark

Taken at Swinderby I assume.
@Creakingdoor: Mercury spillage caused by a heavy landing so I assume from the a/c self.

What, this one?

Mark

Nicely robbed of Spares I see.

As it happens, I am looking for a Mercury or Alcohol thermometer at this very time. I have tried real Chemists, Boots, Lloyds. Nobody sells them down here. All digital, which IMO are as much use as a blokes nipple. (a) Ergonomically, they are more difficult to read than an analogue. (b) That’s when they work 1st time properly!!! (c) Batteries.

With all the panic wrt my baby over new year, we monitered her temp. for the 1st week of the year. The digitals (We have two, a Lloyd Chemist £9.99one and a £30 one from an indie Chemist) are far too unstable, a constant pressure has to be applied to the button for 6 or 7 seconds. Seems a short time but it isn’t with a struggling baby. The Battery ran out, and it’s a Button Cell (3 off)….of exactly the flippin button Cell I didn’t have. Great, 1:30 am and the thermo. is kapput! Good job we had a spare.
So, anti digital rant over. Does anybody know where I can get a real thermometer from. Not a room one, in a frame. A medical one.

While were at it, does the same shop sell real Solder, old stuff with lead in it? New stuff doesn’t do the job properly when mending old circuit boards from cars.

Back on topic.
Somebody at a previous workplace stole a Gallon of mercury from our labs. Yep, a full gallon. It was in 1990. I always wondered what they got for it in £.

Mercury is easy enough to buy… just purchase some vacuum gauges for syncing motorcycle carbs & they come with a small jar of it.

When I was in school we used sulphur to clean up mercury spills….

Where did the mercury come from in this case of XM170?

What, this one?

Mark

There is an account that a brand new E E Lightning was scrapped (or at least never went operational) for a similar reason.

F1a XM170 total flying time 14 mins.

“One difficulty encountered when using these alloys is the ability to contain them. All of the alloys which are liquid at room temperature contain gallium. Gallium is corrosive to various metals, especially when hot. As the temperature of the gallium is raised, it becomes increasingly corrosive, reacting through thicker layers in a short amount of time. One metal which gallium is very reactive with is aluminum. It will corrode through .002″ thick aluminum foil within hours at room temperature, and at 500°- 1000°C, this reaction becomes much faster.

Gallium is non-reactive with other metals however such as molybdenum, tungsten, and nickel.”

Read more: http://blogs.indium.com/blog/indalloy#ixzz1ArSOn1mV

I can remember a relatively young 747 freighter was scrapped after a mercury spill affected the centre section of the wing and made it beyond economical repair.

The RAF C-130’s carry a mercury spill kit in the cargo bay. Mercury is also used in some of the temp stats on the anti ice system of that aircraft.

I believe you can still buy mercury-filled thermometers in the EU but the mercury is some form of ‘safe’ mercury so that if you (or a child) bite through the glass there is no danger from swallowing mercury (only the glass)!

What I cannot get my head around is that amalgams of this type have been and are still used as dental fillings. Still do not really understand why these amalgams do not kill us as these contain a proportion of mercury which is a very toxic heavy metal.

Possibly the same ‘safe’ mercury is used in modern dental fillings? :confused:

Edit: Apparently mercury-filled thermometers are virtually banned in the EU and ‘galinstan’, a liquid alloy of gallium, indium, and tin, is used as a replacement…

…a mouthful of gallium and indium sounds much safer! :rolleyes:

I bought an Hg thermometer a couple of years ago – one of the last as they were claimed by the supplier to be no longer available due to HSE/EU regulations. So you probably cant buy them anymore.

Seems a pity as I recall many a happy chemist undergraduate hour chasing mercury balls around the edges of a fume cupboard with a flask of flowers of sulphur in one hand and a dropping pipette in the other..

And another from my undergraduate days – where does mercury come from – HG Wells…..

Hg being symbol for mercury and HG Wells being a noted author etc. etc. –

Alright I am sorry it is late..

P.S. I would be more worried by copper sulphate eating aluminium…

[QUOTE=JT442;1689021]Over a (short) period of time, the mercury an aluminium oxidise to form black powder deposits as the corrosion. [QUOTE]

It is not an oxidation process but rather the mercury eats into the aluminium creating a mercury/aluminium amalgam, which as you say is a powder. Mercury will attack some other metals in a similar way.

What I cannot get my head around is that amalgams of this type have been and are still used as dental fillings. Still do not really understand why these amalgams do not kill us as these contain a proportion of mercury which is a very toxic heavy metal. Should add I have had all my amalgam fillings (and there are way too many of them!!) removed an replaced with composite fillings.

Planemike

Over a (short) period of time, the mercury an aluminium oxidise to form black powder deposits as the corrosion. Its nasty and the only way to repair it is to remove the affected areas of aluminium. No danger of anyone purposely ruining an aircraft like this… firstly when was the last time you saw a mecury thermometer in a shop?…. they ain’t made any more…. Secondly, its a cargo hold item only.

Mercury spillages are almost impossible to clean up since the droplets spread like ball bearings an you can’t pick the damn things up! A strong vaccuum is the best bet…. THEN remove the affected areas of aluminium…..

This link is quite useful…:

http://avstop.com/maint/corrosion/ch7.html

Picturefrom here:
http://www.projectrho.com/rocket/basicdesign.php

Mercury

There is an account that a brand new E E Lightning was scrapped (or at least never went operational) for a similar reason.

It doesn’t do it instantly, and with modern technical and a/c servicing techniques it should be picked up (if its happened?!) before it becomes a serious issue! But I take your point. Putting an A-380 out of commission with a simple m-i-g thermometer may cause a reduction in whatever airline’s bottom line! But breaking a m-i-g thermometer in the Roach Coach is not going to cause the airframe to go instantly sea-wards at a high rate of knots. Many other things can cause this – but not a m-i-g thermometer!!
HTH
Resmoroh

I’m not really sure that this should be too widely broadcast. Far too many bad people might get ideas.