Modified human marker

[oddpat]

Some faggots at our university library have taken to drilling holes in the doors of the toilet cubicles. When maintenance fills one up, they drill 2 more, sometimes in the same spot.
Which gave me an idea ...
I need to create something similar to the "paint bombs" (the correct term escapes me) which police sometimes put into a bag of cash, which then detonates and covers those nearby in a easily visible substance that is hard to remove.
I need to create a pellet with a maximum diameter of 1/4" and maximum depth of 1/4", one for each side of the cubicle wall. It should contain something brightly coloured which won't harm your eyes, but is hard to remove without special chemicals, and something to deploy said colourant when a drill bit / screwdriver etc. is pressed into it.
My knowledge of chemicals is nill, so I need your help! What can safely deploy said colourant, and what can be used as the colourant?

[Hirudinea]

It sounds like someone is a peeping tom, mabye a stakeout would work better, sit in a toilet and if someone peeks through the hole spray them with pepper spray, that'll learn'em!

[robinhood1532]

I know I'm not the best person to say this, but if you have no knowledge of "chemicals", then you probably should not plan on undertaking this project just yet.:rolleyes:
I can only imagine the possibilities for disaster this type of device has. All it takes is some shrapnel to the eyes and your fingerprints around the hole and even a Peeping Tom can find a way to sue you in this *cough* wonderful country.
If you were serious about making a device that wouldn't harm the culprit, I would do some tests on flesh-analogs first, then even yourself, using an inert substance instead of ink.
As far as the ink goes, I can't help you there, but it would be interesting to use a mild allergen instead. (Although this is probably a worse idea in terms of safety).

EDIT: I hear that the tricky Nitrogen Tri-Iodide stains pretty bad. And its about as sensitive as anyone would ever need - probably too sensitive. If you were feeling brave though, in small quantities this may be worth looking into.
http://www.youtube.com/watch?v=2KlAf936E90 -- NOT my video, sorry if this happens to be from a youtube account belonging to someone here.

[Bert]

I think most places would punish you more for setting an explosive trap in public than for being a pervert in public-

[Woland_91]

Check this out:

http://www.instructables.com/id/Paintball-Grenades/

I can't afford Tippmann squadbusters, so instead I use homemade paintball grenades.

In your case, make a much smaller version of the grenade by filling a shorter length of the tube with paint. If you want permanent ink that stays for days (if not weeks), go look for it in joke shops. Once this is made, carefully strap onto the wall, and remove the safety pin. If it starts to leak, run like hell.

Remember to aim the open end of the grenade towards the pervert!

Good hunting!

[oddpat]

I'm studying engineering, so I might just have the brains to do this... but I need to have a direction to do research in. I can't exactly put a RDX/TNT mixture in there, now can I?
As for the punishment, if you're useless enough to get caught...
Woland, stop posting shit! How would that crap fit in a 1/4x1/4" cylinder?

[Woland_91]

Not fitting that into a 1/4" cylinder, you simply use a smaller tube containing the paint. No matter how small the tube is, as long as a little pressure is applied on it, the surgery tube will spray the paint out. Now, if the size is 1/4", it won't be much, but hey, it's a better idea than slapping a charge on the wall with some paint and hoping the pervert's face doesn't end up like a swiss cheese.

[tranquillity]

Why not fill the hole with some kind of ink or staining agent that reacts on contact with skin. As the culprit drills the hole the chemical sprays out via the drill bit slots and stains their hands or face if they are looking too close. For a simple chemical permanganates seem like the obvious choice; make up a thick slurry of water and finely powdered KMnO4. The purple solution will leave dark brown stains which can last for up to a few days.

As for permanganate in the eyes I am fairly certain that it can cause some damage as it is a strong oxidiser but no idea of the extent.

For the sake of being inconspicuous you cover the first few mm of each side of the hole with your normal filling material and the centre with permanganate or whatever else you choose.

Note: Potassium permanganate will also stain pretty much everything else it comes in contact with too. I have found fairly concentrated acids are the only thing that will dissolve the MnO2 stains.

[robinhood1532]

Why not fill the hole with some kind of ink or staining agent that reacts on contact with skin.

This is taken directly from Wikipedia: "A spill of AgNO3 solution on the skin results in a white stain which turns dark after exposure to sunlight(UV radiation), after long periods of no sunlight the stain may revert back to white/light purple. The stain usually goes away as the skin peels, which takes about 1.5 weeks."

I've spilled a very dilute solution of silver nitrate on my hand and it was darkened for a long time. I survived too....

[drsx]

The bromophenol blue, a skin like colour powder, can absorb to the skin, and above PH 4.6 have a blue colour (PH value from Wikipedia). Needs some days to wear off.
It has two major disadvantage: the high price and the toxicity (irritate the skin and the eyes).

+++++++++++++++++++

Do not sign your posts. - The_Duke

[totenkov]

I was toying with the idea of deleting this thread because it seemed a bit stupid.

Silver Nitrate is not effective enough, extremely expensive, and horrid waste of chems. Don't bother as there are cheaper substances out there. NBKs pocket dragon, a miniature version may be effective, could you imagine...a cubicle door that breaths fire :D

[akinrog]

Silver Nitrate is not effective enough, extremely expensive, and horrid waste of chems.

Assume that the guy (peeping tom) get shot at his eyes with Silver Nitrate, it shall be a mess.

The best shot here, I believe, is to install (i.e. hide) a pressurized container behind the wall, containing some sort of fluorescent (and most importantly harmless) dye which shall be squirted through the hole when somebody drills it.

IIRC, riot cops use some sort of pepper spray on the rioters containing fluorescent dye. Even if the demonstrator escapes, the police collects him somewhere else, since they bear the dye for at least a few days.

However I'm sorry to agree this is a bad thread. :(