How to make something rust really, really quickly?

jill_valentine

Probably not the right forum, but I can't think of where else to send it.

Here's a riddle I'm hoping somebody can science me out of. I'm writing something at the minute, and at a certain point in the story, the character needs to banjax a load of clockwork devices in a hurry.

Is there a chemical reaction that he could set off which would massively accelerate rusting and seize up the gears? I've looked around, and all I can find is advice on creating a cosmetic rust effect.

I'm open to other suggestions too, while I'm at it, just thought I'd ask.

mackg

High temperature corrosion is chemical deterioration of a material (typically a metal) under very high temperature conditions. This non-galvanic form of corrosion can occur when a metal is subjected to a high temperature atmosphere containing oxygen, sulfur or other compounds capable of oxidising (or assisting the oxidation of) the material concerned. For example, materials used in aerospace, power generation and even in car engines have to resist sustained periods at high temperature in which they may be exposed to an atmosphere containing potentially highly corrosive products of combustion.

From wikipedia, not sure if it's any good to you. Someone with more knowledge than me will correct me anyway if it's no good.

Parsley

well rust is oxidation of iron. so by very basic theory using an oxidising agent should accelerate rust. So chucking a load of strong bleach on steel or iron might rust it quicker, but I'd have no idea how quick.

Parsley

or burn it.

krd

Probably not the right forum, but I can't think of where else to send it.

jill_valentine wrote: »

Here's a riddle I'm hoping somebody can science me out of. I'm writing something at the minute, and at a certain point in the story, the character needs to banjax a load of clockwork devices in a hurry.

What kind of clock work devices......And they usually have things like brass wheels and cogs, which are made not to rust.

Is there a chemical reaction that he could set off which would massively accelerate rusting and seize up the gears?

A chemical reaction that would do it fast, would also release a lot of heat fast. Something like Thermite (it's rust and aluminium) is very hot.

The best way to put a clockwork device out of action quickly is to junk it up with something. If you're writing fiction, you have to think of something interesting. In a clock, all it takes is one cog or spring to jam and the whole device grinds to a halt.

Very strong acid would also melt the cogs.

jill_valentine

The devices are all supposed to be very, very old - anachronistically so, it's an urban fantasy story - so it wouldn't be a big deal to have them made out of something rustable. They're security traps, basically, so the character needs to disable them before proceeding and doesn't necessarily have access to the inner workings of every one to gum them up.

If this isn't a goer, I can work something else out, but a chemical vapour of some kind was the first idea that came to mind.

mackg

well I guess if you just banged up the temperature and increased the concentration of O2 in the air it would speed it up, but I couldn't say by how much. I don't think a whole lot of thought has been put into making things rust faster by anyone.

krd

This might work or a variation of it.

http://gomakesomething.com/ht/age/rust-guide/


Spray the tin or iron with peroxide, misting generously. While still wet, sprinkle with salt. Rusting should begin almost immediately, and is sort of fun to watch.

ciaranmac

Rusting happens when metallic iron interacts with oxygen. Moisture and salt act as catalysts to speed up the reaction. Peroxide like krd suggested is an oxidising agent so it will act on the iron more quickly than air will.

Another factor would be applying a positive electrical charge. Galvanised iron doesn't rust as quickly even when the iron is exposed because the zinc plating is more electropositive than iron. Tin plated iron rusts quicker than unplated iron when the plating is damaged because iron is more electropositive than tin. Not sure if this would work in your story but it's another option.

To rust at all, it has to be iron and not any other metal because most other metal oxides form a protective layer (e.g. patina on antique brass) whereas iron oxide flakes away and exposes more iron underneath.

HTH

ZRelation

Pouring some Picric Acid (http://en.wikipedia.org/wiki/Picric_acid) on the gears won't rust them but once it dries out it might just mess up them up enough to stop them working.

unfortunately

I remember watching a video of a guy trying to make Iron oxide. He put a nail in a salt solution and connected it to a car battery - after circa 15 mins it was rusted pretty bad.

ozmo

jill_valentine wrote: »

Probably not the right forum, but I can't think of where else to send it.

Here's a riddle I'm hoping somebody can science me out of. I'm writing something at the minute, and at a certain point in the story, the character needs to banjax a load of clockwork devices in a hurry.

Is there a chemical reaction that he could set off which would massively accelerate rusting and seize up the gears? I've looked around, and all I can find is advice on creating a cosmetic rust effect.

I'm open to other suggestions too, while I'm at it, just thought I'd ask.

I used to put iron nails in a solution of Copper Sulphate and water.

Goes rusty in seconds - while you watch.

SOL

Now if the things that needed to be banjaxed were made from aluminium, they could be banjaxed quite spectacularly by putting some mercury in and giving it a scratch...

Check it out for videos on youtube

jill_valentine

Coming at this from a slightly different angle, would seawater or sea air have a corrosive effect on bronze clockwork? I know it would encourage the green patina, but would that be enough of a surface area change to interfere with clockwork?

ozmo

jill_valentine wrote: »

would seawater or sea air have a corrosive effect on bronze clockwork? I know it would encourage the green patina, but would that be enough of a surface area change to interfere with clockwork?

Bronze or brass is fairly stable. They make ship propellors and portholes etc out of it and it survives well in seawater for over a hundred years....

But if there is a spring in the clockwork - ie. its not using weights as the power source- that will likely be made of spring steel - that will rust fairly easy with any of the suggestions above.
bronze is useless for springs.

You mentioned you wanted a mist vapour... A friend wanted a brushed look on a piece of metal so he put it in weak battery acid (sulphuric acid) and passed a current through it overnight while left out on a balcony..(google electrolysis).. The vapours burned holes in all the neighbours washing that was left out... Really Not a recomended thing to do irl... But might suit the story if it was done in an enclosed space?

bduffy

Most metals develop an oxide layer when exposed to atmospheric conditions. For iron it's rust, for copper it's the patina that was mentioned earlier. In both cases the deterioration of the metal is slowed by the reduced ability of oxygen to get to the metal itself. Therefore to accelerate the rusting sufficiently an oxidising agent would need to leave a porous oxide where oxygen can still get through to the metal.
So in brief the character would need to use a deoxidiser to remove the protective oxide and then follow up with a very strong fuming oxiding material (such as the hydrogen peroxide as mentioned earlier or else a strong acid). This isn't practical so.....:)
Alternatively, if it's just the seizing that's required a fuming organic componds that binds the gears would probably make sense.
Most glue's don't fume (not good from a H & S perspective), but acrylates (and cyanoacrylates - super glue) are volatile enough assuming the solvent doesn't evaporate too quickly.
Silicones are extremely volatile and are banned from spray booths as the residue can stay and contaminate surfaces for weeks.
A 2-pack (an epoxy and an amine) could settle on the metal and react to form a strong urethane mixture. You only have to use the five minute Araldite product to see how bad the smell can get.
The kinetics and so on are fiction (although it would make a nice college project) but the chemistry could be argued....

OP, Best of luck with the (non-scientific) writing

eskimocat

I wonder if the character could have a handy canister of dry ice available... would that be enough to weaken the integrity of the internal structure of the mechanism if it was sprayed into it and enable him/her to shatter it with a well aimed kick?

(coming from the totally non scientific point of view, of course ) feel free to bring the science!

Tzar Chasm

OP, I'd suggest you find out what FIAT made cars from in the eighties and construct the mechanisim from that

jill_valentine

Tzar Chasm, I laughed at that and then felt super old for getting it.

krd

If you want to melt the cogs. You could use termite.

It's a little spectacular. It's aluminium grains, and rust. When you ignite it, it burns at incredibly hot temperatures and will melt through nearly anything, and cause nearly anything to melt.