this is a trick i discovered as a kid, thought some of you may find it usefull as an improvised self defence weapon, espcialy for any Female forumites :)

1) obtain or empty an aerosol can (females could use a small purse sized body spray can)

2) spray some of the contents into the lid (a snif test will make it seems that the contents are genuine)

3) put your empty can in a bowl of boiling water and release any gas that builds up by deperessing the nozel as in normal use.

4) repeat #3 until your 100% sure than no more gas will escape, then let it cool to room temprature.

---You NOW have a can with a vacume in it! ---

5) sellect a liquid you want to fill your can with, chilli oil is a good one! or conc ammonia. (avoid acids and use common sense)

6) pull the spray nozel off the can then invert it into your liquid, depress the plunger and your can will start to fill up (let it fill) :)

7) when done wipe your can clean and get a can of Butane lighter gas.

8) select the lighter gas nozel that fits into your new aerosol nozel then proceed to fill your new can with the pressurised butane as if it were a big lighter :)

(point #8 CAN get a bit messy sometimes, so take adequate precautions)

9) replace the spray nozel, test, than clean your can, pop the lid back on and your done :)

on occasion you may need to widen the nozel hole with a pin/needle to give it greater spray distance or if your liquid is particularly viscous.

please be carefull with these devices so that you or a child doesn`t use it by mistake !!!

EDIT: between points #4 and #5 you may put the can in the freezer for an even greater vacume effect.

Enjoy :D

A few calculations for those who like that:
Considering a 250 mL spray can. Let's consider perfect gas inside the can.
PV=nRT
So if you empty the can just after boiling it (373 K), you have n=PV/(RT)
10^5*0.25/(8.314*373)=8.06 mol

So at 25°C, you have a pressure of 8.06*8.314*273/0.25=73125 Pa
So you get 3/4 atm in the spray can.

This is a pretty high pressure to suck up something, isn't it ?
Why not adapting, once you have put the pression around 1 atm inside (to do that you just heat a little the can while pressing to make sure it's really empty), a vacuum pump to the nozzle ? Like that you could put more product in a small spray can. Great to spread lots of chemicals in a crowded place.

Fucking metros....:mad: ;)

as an adjunct to this thread, rather than it be just a "stand alone instruction manual"

i invite discourse as what would constitute a good filler for these aerosol cans, maybe petrol with a lighter attatched as single use flame thrower?

this part i`ll leave to the imaginations of forumites.........

it`s YOUR thread now :D


Arthis; thanx for the maths it`s added considerably to my post, your a braver man than me to work all that stuff out! ;)

I was just thinking of something like this, except using an inhaler(the type that give precisely equal amounts of the solution with each use). I was thinking that since you can use an exact amount of a gas as a knock out spray. Find the amount of HCN that knocks the victim out without killing and have that amount be let out every time you spray it etc. I dont understand the point of using irritants in it as you can purchase Mace etc from almost any store here. But other chemicals might have some use. The hydroxides react with aluminum IIRC so they would be out of the question, most corrosive chemicals do unfortunately.

forgive me if i`m wrong, but i`m fairly sure that Hydrogen Cyanide is a gas at RTP? and so how you fill your aerosol is beyond my experience unless you can obtain it liquified somehow?

secondly, Aerosol weapons such as Mace, pepper spray and the like are unavialable here in th UK, at least to the general public anyway.

you mention the Asthma type aerosols, i`ve never tried them myself for refills, but i imagine that it may not be possible with the above method since they have a float valve that limits the outgoing (making the vacume creation difficult) and i expect it would either restrict or make impossible the intake of a liquid/gas just as difficult or maybe impossible? i AM only guessing here and this would be a good subject for experimentation :)
of course having said that, if it were to be entirely feasable, the sytem employed to deliver this against your assailant(sp) attacker would be subject to debate also, i personaly beleive that arms length is TOO close!

you are indeed correct, hydroxides can be quite nasty with certain metals (some, namely LiOH will even attack glass!) hence in point #5 i stated to use common sense. conc Ammonia seems to quite ok with many metals, with the exception of copper over time.

as a knockout agent, most in reality seem patheticly slow as compared to the crap on TV and at best in TV time done in reality will get you HIGH and give a pounding headache about 10 mins later, i`m sure NBK would have some info as to what would be the most effective in reality.
but ethoxyethane (ether), 111 trichloroethane and chloroform are as i`ve already stated lousey to use, kills brain cells lovely tho :)

IIRC HCN BP is about i think at 25* C im not sure, i know that it isnt that hard to liquify.

It's about 79&degF. I've poured HCN into the palm of my hand and watched it boil. :) BTW, I wouldn't do that again, knowing what I know now. :eek: ;)

HCN is an "all or nothing" weapon. It either kills you, or has no effect, with no middle ground. So, there's no "knocking" someone unconcious with it, unless it's a prelude to their death.

As a general rule, anything that'll render someone unconcious quickly enough to be tactically practical, will have a high mortality rate. Witness the russian theather rescue. Using a synthetic opiate, they knocked out everyone in the theather quickly enough that the terrs weren't able to kill anyone. But, in the process, the anesthetic killed 1 in 6 hostages.

Only when used under very controlled conditions would an anesthetic be useable.

Even then, since you're not doing it in a hospital setting with access to a respirator, oxygen, cardiac drugs, etc, you'll be taking a chance of the person dying on you anyways.

So, if you have to capture a specific person alive and undamaged, then you'll have to use something else, like a TASER or some kind of man-trap.

IF you don't care about fatalities, and the need for rendering a group of people unconcious rapidly is important, but killing everyone present isn't desireable, then I'd use Methylene Chloride. Look for my thread in the CW section called "MCX, the triple threat agent" for more details. Though, if you use too much and there's an ignition source...crispy critters. :(

Otherwises, use pure HCN at .3 oz/1K CFT, to exterminate all life within a few moments. :)

As for the aerosol cans...

Drill a hole in the bottom after venting all pressure out. Rinse out the container with a suitable solvent. Cool the can down to whatever temp is needed to do the next step. Pour in about half the volume of the can with your desired chemical dissolved in a sutiable solvent and low boiling point pressurizing agent and seal the drill hole with a gasketed self-tapping screw or rivet.

When it reaches room temp, the low BP agent will "boil" inside the can, creating an above-atmospheric pressure inside the can. :)

ok, this is somewhat on the stupid side, but CO2 in concentration of i think over 15% will knock a person out in a breath or two, i'm not completelly sure on the duration, but i know that the person just passes out, and i think if you just get them to fresh air in a min or so they would be ok. also, that this stuff is abondunt, cheap, and safe, is a plus. so if they were in a room, and you just vented the CO2 next to the door, if the windows were closed, i'd give them a min

Little thing called "glottal (SP?) seizure" would kill them, unfortunately. :(

Exposure to a suffocating atmosphere triggers the glottal seizure (part of the mamillian dive reflex), causing the muscles that seal off the airway to seize shut, to keep out the CO2 (or "water" as the brain thinks of it).

Once seized up, it would require a tracheatomy and postive oxygen resicitation to release it.

And the quantity of CO2 would be very large. Also heavy, since each cylinder weighs about 15 pounds empty, plus the 20 pounds of gas, times the number of clyinders required to gas even a smallish room.

About the flamethrower that you spoke about, yt2095 (even if a little off-topic): you can buy any spray can to use as a small flame thrower, we all have, when younger, tried it with a deodorant spray. No need to make your own. There are normally no risks of backfire.

I've always dreamt of using jellyfishes to make a powerful product, to be used in spray cans for example. Spay it to the face, even a small quantity in the eyes could turn bad. And it burns, depending on the jellyfish: here there are some sometimes that burn a lot. eheh

I have often though of obtaining a collection of highly venomous animals (legally, of course) for weaponry plans, and jellyfish are, as a species, perhaps the most venomous animals in the world, with the possible exception of snakes. Many believe the box jellyfish to be the MOST venomous animal there is, and there are plenty of others that range from no sting to "your lucky if you live" level of danger. I have no doubts that their poisons would be more effective as a spray than pepper spray or mace, but I think they may cause more lasting harm. If your not worried about lasting damage, why not just fill an aerosal can with acid? (although you would have to do something to prevent the acid from eating through the metal can).

-Ancalagon

It would be hard to rely on the metal can being protected. Even a gradual reaction between the acid and the can could over-pressurise the can resulting in it exploding, or spurting acid when you least expect it.

Does jellyfish venom work if it's not injected? Maybe into the eye tissues would be a sufficient means of entry?

It has been mentionned that acid would not be adequate, you do not make an aerosol spray from scratch but you use OTC sprays, so opening it would not be as interesting. Maybe nitric acid, conc enough it won't attack the can (cans are made of aluminium).

You may not want to make a self-defence aerosol, but anything, and a can full of jellyfish poison, pure, would be perfect to protect the access to a door or anything. Of course gloves will reduce your efforts to nothing, but noone takes precautions to touch the handle of a car/house door [remember the movie "the Jackal ?].

[edit]: to Anthony. Of course it works a little: when touched by a jellyfish it burns. At least Mediterranean ones. (I experienced that, more than once). The fact is it's soon washed by the sea, etc. But with a spray, you pulverize a large quantity, and it's not washed. It will not kill a man (you would need to stay in prolongated contact), but some weak people can collapse. It would be an expensive stuff, time eating to prepair some. In the eyes, it would surely cause much damages and life-long lesions.

Jellyfish toxins are stored in tiny barbed stingers called "nemetocytes". The nemetocytes are triggered by contact, injecting the toxic protein underneath the skin.

The toxin is too large to penetrate the skin without being injected, and the nemetocytes are triggered by contact, thus your jellyfish extract would be like a fired bullet...harmless...because the barbs aren't going to survive being aerosolized without being triggering.

This sin't to say you couldn't use a water ballon filled with box jellyfish tentacles to drop on someone. :) As long as the tentacles are intact, and haven't been dried, then they'll trigger upon impact or when the victim goes to wipe them off. :D

But for carrying around? :confused: Impractical and needlessly complicated.

If you're going to be spraying anything, you have to RTPB "Plan for failure", and assuming that it'll drift back to you or rupture in your pocket. Do you really want to be carrying around a can of fuming nitric next to the family jewels? :eek: Or get a mist of concentrated lye in your eyes? Not me.

Now, if it's a set up weapon, then that's different. In which case, load it up with the most vile and toxic things you can find. :)

If you open up an aerosol can and look inside there is some kind of thin yellow/gold coating on the inside on the metal. It might not be on all aerosol cans but does anyone know what the coating is and what is it for? protecting the metal? The can was a Lynx deodorant by the way.

my main concern about acids in the can wasn`t so much the can itself but the steel spring in the nozel plunger, i`ve found this out accidently using the plastic pump spray bottles, they work great for a while with a plethora of diferent chems, it`s the spring that doesn`t stand up to abuse though, the same applies to water pistols unfortuanetly :(

Going back to the original method, if you can't get you hands on a vacuum pump you should be able to achieve a better vacuum by adding a little ammonia, or other volatile solvent, to the can after it has been depressurised, and then repeating the boiling process.

This way some of the ammonia will condense back when the can is cooled, further reducing the pressure.

And how will you empty the ammonia from the can if there's already underpressure ? The principle of the stuff is to use the vacuum to pump in some liquid. If there's already ammonia in here you won't be able to take it away, and you lose some place.

Arthis, quite true.

Steety i can understand exactly what your getting at, and at face value it "SEEMS" to be a good idea, but the further de-pressurisation is created by then further freezing the can (between points #4 and #5)
the addition of Ammonia would result in exactly what Arthis said unfortunately.

your principal DOES WORK in certain situations with gasses tho :)
in fact i use Lithium metal in my homemade vacume tubes to remove the oxygen and nitrogen content from an already scarce pressure to create an even greater vacume.
Note: i`m aware it sounds contradictory to "Create a vacume"
but for wants of better terminology, that`s the method i employ for gasses (or lack of)

hope this helps a little?

There would be no way to remove it, you are quite right but if you are filling the can with ammonia its not a problem. Besides the amount we are talking about should make very little difference to the final content of the can.

When not using ammonia I suspect you could use other volatile liquids although I don't know how success they would be.

Thank you, yt2095! I posted on this quite some time ago, looking for a method of getting substances back into the can. I think the best idea was tapping the bottom of the aerosol can and putting in a bike valve. One thing that puzzles me is: How do you know if pressure is building up in the can while you are boiling it? What if you couldn't tell, and the heated contents exploded the can? If the can exploding isn't bad enough, what about the flying boiling water? It makes me shudder to think about it.

The process would still work (in fact should work better) if the can valve is held open.

The risk would come in the possibility of the can imploding when making the vacuum rather than exploding when being heated.

See the calculations I made previously. Using a perfect gas would lead at maximum 3/4 atm. This won't make a spray implode, even if cans are made to resist internal overpressure and not external overpressure.

It's also difficult to say what happens with ammonia, or with any stuff that is a gas at 100°C and liquid at 25°C, because with the pressure being different the boiling point is different. Anyway you have a binary equilibrum with one constituant, with partial pressure, etc... This is not so easy to handle, even considering perfect gas.

Finally, in this method, be very careful that the vacuum will not be totally compensated by pumping up some liquid: it's like Hg thermometer, the vacuum is not enough to pump enough mercury. So you will lose a lot of gas, as you need your spray to spray (!). This may happen to be a little more expensive, and a little less effective. I mean even if it's 3/4 atm, you will not be able to pump:
-
PV=nRT=cte in the can, so 75000*V0, V0 volume of your can
if P=10^5 , you have then V=V0*3/4
-
... to pump 1/4 V of liquid. Count no more than 1/5 V. This is not much. This will strongly depend too of the density of the stuff you use in your can: mercury creates a great depression, water not much...

points #3 and #4 negate the possibility of explosion.

the bicycle valve although a workable idea wouldn`t pass the scrutiny of an inspection, the idea was to keep the can as "normal" looking as possible so as not to arouse suspiscion.

the butane gas BP -17c (iirc) will provide plenty of pressure to reactivate your can, they use Butane in a good many aerosol products as the propellant anyway. especialy since all this CFC worries, compressed air is used in some products but far to difficult for the home kitchen lab.

in all my uses of these, i`ve never once had a failure and always been able to get the cans well over half full.

give it a shot :)

if your worried about pressure building up you can do it the way NBK suggested and drill a hole in the bottom. In preparation for this experiment i foudn an empty can. then i found some 3" pvc left over from another project that had an end cap glued on it, so i drilled a hole and put a screw in the bottom. now when i drop an empty/near empty can in the screw punctures the can and vents any remaining pressure and possibly launches the can out of the PVC. all i need is a gasketed screw and i'll be set

I'm not satisfied that all pressurised aerosol cans are made of aluminum, but can't bring up counterexamples at the moment.

The goldish colour somebody earlier in this thread remarked upon is called a "gold iridite" finish, which, if I don't make mistake, is similar to black anodising: an acid bath surface treatment of aluminum to lend the treated surface greater resistance to corrosion, and, if I'm still not making mistake, lends surface tension and a degree of hardness to said surface.

Since I have no aerosol cans to muck with at the moment, the question occurring to me concerns the feasibility of filling the can, after having removed the nozzle cap, by syringe through the exhaust tube.

I don't know that this particular post is strictly on topic in this particular thread, but was unable to find one that looked more suitable and am unwilling to initiate a new thread for what may be a stunningly stupid idea.

In some Clancy-like novel that is now stupidly out of print, whose title I even more stupidly cannot recall, there was a description of a grenade-like weapon that operated first by releasing large volumes of some highly volatile (and, of course, extremely toxic) fuel before detonating. The idea, as explained in the novel, was to effect maximum casualty with minimum damage to surrounding structures - in this novel, the "structure" was a schoolbus full of Anapolis cadets bound for some international function at the White House (where else?), and the defuncted cadets were replaced with lookalikes recruited from elsewhere for nefarious purposes - but the bus itself had to be more or less preserved.

I'm having a little bit of trouble understanding how an atomised fuel so atomised in a confined volume could be ignited without basically pushing the sides and roof away from the center of the structure. A small experiment I tried a long time ago involved an exhausted can of lighter fluid whose top had been removed, and LIGHTLY re-infused with gasoline and then ignited. Fucker took off faster than a jackrabbit running from a wolf. If that can had been ignited SEALED, it would almost certainly rupture (I believe the crimped-on top would have achieved low orbit).

Are there atomised fuels that can burn in a confined volume without exploding?

I have one of those huge cans of wasp spray in my vehicle. It shoots a solid stream for 15 feet. I don't know what a good shot of this would do to someone, but even a whiff of this stuff makes me run for fresh air. It's also inconspicuous, "hey, I have to go into seldom occupied buildings all the time". It's a lot cheaper than pepper spray (same size/volume spray). I like the idea of OTC sprays, it's harder to prove intent/premeditation. Are there any more affective OTC sprays? Anyone had any personal experience with wasp spray?