Would liquid Nitrogen really freeze and shatter a hardened disc detainer locK ??

Alan_H_1991

Where can you buy it??

How much does it cost??

What if you spilled some on your skin or tyre?

krd

Alan_H_1991 wrote: »

What if you spilled some on your skin or tyre?

You would get a very bad burn if you spilt it on your skin. If you dipped your hand in it, you'd probably lose your hand.

If you poured it on a tyre, the tyre would probably explode.

Turtwig

krd wrote: »

You would get a very bad burn if you spilt it on your skin. If you dipped your hand in it, you'd probably lose your hand.

If you poured it on a tyre, the tyre would probably explode.

This isn't entirely accurate and I don't think I'm the person to adequately explain why. Liquid Nitrogen is incredibly complex and the physical and chemical phenomena involved in pouring liquids make things even more complex. So what can I say? Oh, you can pour it on your hand and avoid getting burned. Dipping your hand into it though is definitely a unwise decision. The outcome of pouring it onto a tyre depends exactly on how you pour it. Any takers for this one?

First things first.

lukich79

I am not sure what a disc detainer lock is. But I assume its of a metallic construction.
I reguarly use liquid nitrogen in my job. I work in a heavy transport engineering facility. We use the liquid nitrogen to shrink brass bushings.

We drop the bushing into a vat of liquid nitrogen and leave it there for some time. The freezing temperature shrinks the bushing, the bushing must then be swiftly removed and installed into its bore before it expands and fills the bore.

I have also seen the liquid nitrogen being moved in stainless steel vessels. I would say that it wont cause metallic objects to shatter (shrink yes). I have however seen apples and oranges being dropped in and subsequently shattered.

ApeXaviour

krd wrote: »

You would get a very bad burn if you spilt it on your skin. If you dipped your hand in it, you'd probably lose your hand.

While care should obviously be taken when handling liquid nitrogen, I think you might be exaggerating quite a bit with your claims. Liquid nitrogen boils at -196C and you can actually (though I don't recommend it) dip your hand in very quickly without any harm coming to you. Much in the same way you can dip a wet hand into molten lead (as demonstrated on mythbusters) because the evaporating water around your hand creates a buffer between you and the molten metal, the "boiling" liquid nitrogen vaporises when it comes even close to the heat of your hand. It then rapidly expands buffering your skin from direct contact.

Of course if you do this for any longer than a fraction of a second, that heat will be used up, and direct contact will begin to freeze the water contained in your skin cells. The tiny ice crystals in formed will tear the cell membranes, killing the cells... leading to cold "burns" and eventually (if left for longer) frostbite.


Oddly enough the greatest dangers of liquid nitrogen come from explosions and asphyxiation. If you're in a badly ventilated room and you spill a dewer of liquid nitrogen, it would evaporate significantly larger volume (~800 times) than when it was a liquid, potentially displacing the oxygen containing air from the room. This why many physics labs have oxygen alarms that go off if the O2 percentage in the air drops below 18 or 19%.

The rapid expansion into a gas at room temperature is the same reason for the explosions. You'll notice liquid nitrogen containers are never actually fully sealed. Even the most insulating of containers cannot prevent heat leaking in... and if the container is sealed (as sometimes happens accidentally), the liquid will "want" to turn into a gas as it warms up, increasing the pressure until the container explodes.

krd wrote: »

If you poured it on a tyre, the tyre would probably explode.

An inflatable tyre? If anything its cooling, would temporarily reduce the volume of the air inside, making it appear deflated. It might harden the rubber at the same time though, which *may* cause it to crack as it deflates. An explosion is unlikely however, unless you were continually inflating it while pouring liquid nitrogen on it. Or if you (for some unknown reason) filled the tyre with liquid nitrogen. You would have to be pretty stupid to do that though.


Sorry OP I don't know what a "hardened disc detainer lock" is. Though if you mean hardened as work-hardened, where there's an already an existing plastic deformation of the metal, or epitaxial strain, then perhaps it may push the metal beyond its limits. Practically however, I have no idea.

FISMA

Alan_H_1991 wrote: »

What if you spilled some on your skin or tyre?

Liquid Nitrogen (LiN) can be CAREFULLY and CORRECTLY poured on to your skin without any problems for similar reasons that people are able to walk on coal.

If you open your hand and allow LiN to be poured, so as to not accumulate and run off your hand, then the later of sweat/moisture will create a layer of vapor that will protect your hand from the extreme cold.

However, if you had a lot of LiN and continued to pour it, the layer of moisture would eventually "wear" away and you would be in serious trouble.

Have a look at youtube and you will find people putting in to their mouths. Not sure how one practices this and to tell the truth, I really do not want to know.

For those that believe walking on coals is mind over matter, I suggest they stand still and we'll see what happens

Capt'n Midnight

liquid nitrogen is relatively cheap

you need an expensive container for it though , you can't just wander in off the street with a thermos flask

krd

ApeXaviour wrote: »

Oddly enough the greatest dangers of liquid nitrogen come from explosions and asphyxiation. If you're in a badly ventilated room and you spill a dewer of liquid nitrogen, it would evaporate significantly larger volume (~800 times) than when it was a liquid, potentially displacing the oxygen containing air from the room. This why many physics labs have oxygen alarms that go off if the O2 percentage in the air drops below 18 or 19%.

Nitrogen has another strange property. If you're in a room where nitrogen has pushed out all the oxygen, your lungs will still breath the nitrogen and your body will still thinks it's getting air. You'll be completely unaware you're suffocating until you keel over.

I think NASA lost a few people through nitrogen asphyxiation.

Capt'n Midnight

krd wrote: »

Nitrogen has another strange property. If you're in a room where nitrogen has pushed out all the oxygen, your lungs will still breath the nitrogen and your body will still thinks it's getting air. You'll be completely unaware you're suffocating until you keel over.

I think NASA lost a few people through nitrogen asphyxiation.

It's not that strange a property.

Argon is just the same, in fact any inert odourless tasteless gas with a similar density to air will be have the same. Lighter gases (Helium) will chill your lungs faster and give you a higher pitched voice. Heavier gases (sulphur hexa fluoride, worst greenhouse gas evar ) won't chill your lungs as quickly but will give you a deeper voice.

Maximus Alexander

Yeah, it doesn't seem that strange when you consider that air is predominantly made up of Nitrogen. If we reacted badly to it, ours would be a rather uncomfortable existence.

maximoose

Sounds to me like you were clamped :pac:

Tzar Chasm

lukich79 wrote: »

I am not sure what a disc detainer lock is. But I assume its of a metallic construction.
I reguarly use liquid nitrogen in my job. I work in a heavy transport engineering facility. We use the liquid nitrogen to shrink brass bushings.

We drop the bushing into a vat of liquid nitrogen and leave it there for some time. The freezing temperature shrinks the bushing, the bushing must then be swiftly removed and installed into its bore before it expands and fills the bore.

I have also seen the liquid nitrogen being moved in stainless steel vessels. I would say that it wont cause metallic objects to shatter (shrink yes). I have however seen apples and oranges being dropped in and subsequently shattered.

this is your solution, if you can immerse the lock mechanisim for long enough the disks may shrink enough to allow the locking bar to fall, this would get the clamp off the car WITHOUT DAMAGING it, thats yer key isue when dealing with Private clampers, as long as you dont damage their clamp in any way you can remove it, but shatering bits willlead to another fine.

I wonder would the pipe freezing kits that plumbers use work in the same way??????

Gurgle

Tzar Chasm wrote: »

if you can immerse the lock mechanisim for long enough the disks may shrink enough to allow the locking bar to fall, this would get the clamp off the car WITHOUT DAMAGING it,

Hang on, its probably safe to assume that the parts of the lock are all the same metal so all would shrink an equal amount and it wouldn't fail.

I suggest you find someone who can pick the lock for you instead.

I wonder would the pipe freezing kits that plumbers use work in the same way??????

I think they just freeze water in a short section of the pipe, creating a plug of ice and preventing big spills during a quick swap-out of a faulty fitting.

Capt'n Midnight

http://www.bikeforums.net/archive/index.php/t-67282.html

Conclusion. The use of freon to defeat a lock is not a viable technique. My test was against a single lock. Other locks may or may not be susceptible to this attack. However, the lock I used was a low end lock and would likely be most susceptible to attack.

...
I froze my specialized bike computer with dry ice when I was bored one day, after it warmed up it kept working, I still use it now. I froze a small pad lock with liquid nitrogen and dropped it onto a hard floor, nothing happened.

...

It may be that this is a good reason for case hardening locks as opposed to through hardening. A case hardened lock would have more resilient metal at its core to resist shattering and a very hard outside to resist cutting. It's kind of like how a samauri sword was tempered or how your teeth are comprised.

http://www.newscientist.com/article/dn13962?DCMP=ILC-hmts&nsref=news6_head_dn13962

Cheap, non-alloyed steel typically becomes brittle at about -30 ºC. Adding expensive metals like nickel, cobalt and vanadium to steel reduces that temperature by strengthening the connections between grains.

and guess what metals they add to steel to make locks ?

krd

Idiots with liquid nitrogen. Worth seeing

http://www.videobash.com/video_show/how-ln2-exploding-and-loud-236297?utm_source=mgid-widget&campaign=mgid-widget&utm_medium=exchange


Well now I know you can carry it around in a thermos flask......Where can I get some?