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Topic: Corrosives  (Read 25028 times)

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Offline Arkcon

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Re: Corrosives
« Reply #15 on: December 13, 2008, 11:34:30 AM »
* Sorry to everyone for replying to my own post, but I'm trying to deal with the login timeout, and the edit timeout, and these long stories of mine are hard on a slow typist like me*

I'm a fan a of show, called Breaking Bad, it's about an Albuquerque high school teacher, who's decided, for various reasons, to manufacture crystal meth.  A charming topic, I know, but the art is in the execution, not the nobleness of the story.  IMHO.  YMMV. 

At any rate, to steal a reagent they need, they melt through a hardened steel door lock, in a few seconds, using chemistry -- they use thermite.  Like I said, extraordinary results require extraordinary methods.

Although, on that show, I'm not very impressed with what they had him do with mercury fulminate.  But then again, it is T.V., some suspension of disbelief is required from the viewer.
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Offline azmanam

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Re: Corrosives
« Reply #16 on: December 13, 2008, 12:21:35 PM »
While we're ripping on bad chemistry in tv shows...

I was watching Fringe a few weeks ago.  It's a story about fringe science and science that pushes the boundaries of the imagination and/or reality.  'downloading' the thoughts directly from the brain of another person (a dead person, actually).  Things like that.

Anyway, the main scientist in the show for some reason really needed LSD to help another character and to perform whatever fringe science phenomenon was at the center of this particular episode.  So he made it himself in his lab.

In a single afternoon.  I don't think so.

In another episode, he had developed a 'radio' spectrum outside the known electromagnetic spectrum for clandestine communications.  He had also developed some iridium compound that could be given to humans and have humans be 'wireless receivers' for the transmissions.  Basically beaming thoughts directly into peoples' minds.  He had tested it on some humans a few decades ago, and lost track of the subjects for reasons that are explained if you watch the show.

Anyway, he catches up with one of the subjects because some rogue operation has perfected the clandestine transmissions, and this person was intercepting them (the main scientist is on the side of the good guys).  He claimed that the dose of the iridium compound he gave the subject decades ago was far to small of a dose for this kind of reception capabilities.

So he claimed that the iridium complex self-replicated in the body over time.  Got that?  One of the least abundant elements on Earth self replicated.

But overall, I really enjoy the show.  I just get frustrated with some of the liberties entertainment writers take with science occasionally.
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Offline uperkurk

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Re: Corrosives
« Reply #17 on: December 13, 2008, 12:26:18 PM »
OK I fully understand what your saying. Films can be misleading when it comes to things like this. And I don't expect to pour some acid on a truck and it will dissolve infront of my eyes. But I have found a thin sheet of steal over the park and it would super rusted and I hit it with a pole and it was just breaking up into little bits, I know this is water that is causing it to rust but I thought that some kind of acids would have the same affect as the water but it a shorter period of time.

Offline macman104

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Re: Corrosives
« Reply #18 on: December 13, 2008, 12:36:44 PM »
Anyway, the main scientist in the show for some reason really needed LSD to help another character and to perform whatever fringe science phenomenon was at the center of this particular episode.  So he made it himself in his lab.

In a single afternoon.  I don't think so.
I saw that part, that was too funny!  I was watching Fringe, but I stopped.  Too many other shows better than it, but it is kind of a fun little show occasionally.

Offline Arkcon

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Re: Corrosives
« Reply #19 on: December 13, 2008, 03:18:37 PM »
One of the things universally damaging to all grades of steel, to some extent, are halides -- that is salts of iodine, bromine, fluorine and most importantly, chlorine.  That's important, because the planet Earth has oceans of it, not to mention that we all carry a supply, pumping within us.  I wouldn't be surprised if a sheet of steel rusted out first at the spot where a drop of my blood hit it, once.  But I wouldn't expect gallons of sea water to get me out of prison any faster than someone with strong hammer and lots of dedication, unless the bars were never checked for weakness.

OK, in a race to ruin a steel bowl full of moderate strength acid, I'd expect moderate strength hydrochloric acid to beat out sulfuric acid of similar strength.  We're talking months here.  I suppose the big winner would be nitric acid, it has oxidizing power, the others would need oxygen in the air to help them attack iron.  But still, even in modern countries, the legal system probably works faster than these acids.
« Last Edit: March 23, 2014, 09:50:00 PM by Arkcon »
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Offline macman104

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Re: Corrosives
« Reply #20 on: December 13, 2008, 05:54:03 PM »
OK, in a race to ruin a steel bowl full of moderate strength acid, I'd expect moderate strength hydrochloric acid to beat out sulfuric acid of similar strength.  We're talking months here.  I suppose the big winner would be nitric acid, it has oxidizing power, the others would need oxygen in the air to help them attack iron.  But still, even in modern countries, the leagal system probably works faster than these acids.
Not to mention, you'd have to figure out a way to "soak" the bars in a constant fresh bath of the acid (and not have the contraption be obvious).  Interesting task, since most bars would be vertical (although, in those fancy modern prisons do they even use bars, they've got that high tech plastic stuff!)...

Offline uperkurk

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Re: Corrosives
« Reply #21 on: December 13, 2008, 06:24:43 PM »
Ohh ok thanks for that information. I was just using the bar as an example. What he did was squirt the acids down the drain in a room, and when it got to the bottom it just sat there eating away at the steel.

Offline Arkcon

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Re: Corrosives
« Reply #22 on: December 13, 2008, 10:17:43 PM »
Ohh ok thanks for that information. I was just using the bar as an example. What he did was squirt the acids down the drain in a room, and when it got to the bottom it just sat there eating away at the steel.

Humph.  Really?  You can buy quite concentrated sulfuric acid at the hardware store, for dissolving clogs.  It can damage old pipes, but using it in a prison break, when many viewers have possibly bought it themselves, seems like asking for too much suspension of disbelief.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline uperkurk

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Re: Corrosives
« Reply #23 on: December 14, 2008, 09:35:40 AM »
Someone said about thermite which indeed would just burn straight through the bars but obviously would make a hugh amount of noise and set of every smoke alarm lol. The way I see it is if you could get your hands on a small amount of acid of somekind (sulfuric because its the most powerful) and over a period of say a month that pipe would just keep corroding bit by bit and it would eventually be so weak you could just kick it and it would break off. It's just about finding a cleaning substance or something that has certain chemicals in it so when mixed become violent and become a corrosive.

Offline Arkcon

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Re: Corrosives
« Reply #24 on: December 15, 2008, 09:40:06 AM »
That is presumably what the real life people in the Mexican prison did.  What really happened was neglect of maintenance, and guards checking what prisoners were up to.  Presumably, Alcatraz was inescapable, but by playing the system, a few guys were able to break out, 'tho there's no proof they made it to shore. 

But you've got to realize, when we scoff at the concept of the magic reagent in a tube, we don't want to argue with you, but the chemistry involved is ludicrous, for reason others have tried to explain.   And I've tried to get you to look at the big picture -- if such a chemical existed, we'd have to design structures to resist it, if we couldn't, we would radically change our culture, say prisons on island, or no bars, just a cheap wire fence and more guards with a shoot to kill mentality.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline uperkurk

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Re: Corrosives
« Reply #25 on: December 15, 2008, 09:55:49 AM »
I am trying to look a the bigger picture but realistically you would need thousands of tonnes of acid to corrode an entire building if thats what you mean. I can across nitric acid on wikipedi. It can corrode copper in a matter of seconds... so applied to steel surely it is powerful enough to corrode it? The copper actually dissolved not to mention just corroding it to make it weak. Anyway nitric acid lets of alot of smoke so thats not really ideal lol

Offline azmanam

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Re: Corrosives
« Reply #26 on: December 15, 2008, 10:14:42 AM »
Copper doesn't actually dissolve in nitric acid... It undergoes a redox reaction with nitric acid to form copper nitrate.  This, being a chemical reaction, is not technically a dissolution.  Also, steel is mostly iron.  Unfortunately, you can't make generalizations for one metal based on reaction with a different metal.

dissolution: http://en.wikipedia.org/wiki/Solvation
redox reaction: http://en.wikipedia.org/wiki/Redox_reaction
copper nitrate: http://en.wikipedia.org/wiki/Copper(II)_nitrate

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Offline Borek

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Re: Corrosives
« Reply #27 on: December 15, 2008, 02:55:18 PM »
realistically you would need thousands of tonnes of acid to corrode an entire building if thats what you mean.

Good point.

Quote
I can across nitric acid on wikipedi. It can corrode copper in a matter of seconds...

Same point applies - you need a lot of acid, and in the case of the thick copper bar process won't be that fast. But there is more to it.

nitric acid (...) applied to steel surely it is powerful enough to corrode it?

Actually - no. While copper dissolves (let's not be too technical) in concentrated nitric acid, iron is immune due to passivation. Concentrated nitric acid is transported in iron tanks.
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Offline uperkurk

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Re: Corrosives
« Reply #28 on: December 15, 2008, 03:07:53 PM »
And steel is mostly iron.. I think I finally understand lol. This is completely of topic but I dont want to make a whole new thread for a simple question. I have looked on google and cant find and answer. At what tempreture do diamonds melt at? and once there melted what are the transported in?

Offline azmanam

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Re: Corrosives
« Reply #29 on: December 15, 2008, 03:14:18 PM »
Quote
Carbon also has the highest melting and sublimation point of all elements. At atmospheric pressure it has no actual melting point as its triple point is at 10 MPa (100 bar) so it sublimates above 4000 K.[13] Carbon sublimes in a carbon arc which has a temperature of about 5800K. Thus, irrespective of its allotropic form, carbon remains solid at higher temperatures than the highest melting point metals such as tungsten or rhenium. source: http://en.wikipedia.org/wiki/Carbon

It would be much cheaper and easier to transport diamonds as solid diamonds than any liquid form it could become.
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