Dummy C-4 bomb - General prop

[stan]

So I've been wanting to make one of these for a while. Not from a specific movie or show, but very much something you would expect to see in one. Going to try and go for a small C-4 bomb with electronic detonation unit / timer.

an example of real plastic explosive (C-4):

for the C-4 i discovered that polymer clay from the craft store is a perfect thing. I got some 1lb blocks, they color is "ivory" to best mimic the off-white of C-4. without having handled any in real life, this seems as close as I would hope to get

i'm going to try and press these into a flat sided shape for the final unit.



as far as the timer / detonator unit, i haven't decided on a final design. i know i can picture lots of movie bombs in my head but i cant remember anything specific and not much turns up in a web search.


this is a pretty interesting looking design, that has a lot of the features i plan to use.

 

[Node Nine]

I think that is damn cool and have thought about doing it myself but be careful about taking it out in public

 

[stan]

ordered some electronic bits and bobs for the detonator unit.

going to run it with an arduino duelmilanove (sp?) with screw shields attached. this will allow me a lot of freedom in weaving wires all over the place, both functional and nonfunctional.

here's an arduino with the screw shield:

planning to use 4-digit 7-segment displays, ordered a few sets up in blue. also getting the interfaces to drive them with the arduino. these will display the count time and anything else needed.

also thinking about what kind of keypad to use. could go for the phone button style units, or maybe something else?



any input would be welcomed!

 

[stan]

as far as how i will program the unit, i think i will put a beepy speaker thing in the circuit so it can beep with increasing speed as the countdown nears finish.

going to need some basic buttons for starting the count, resetting the count, and setting the count length.

 

[Skaught]

Just be careful or you could spend some time in a very real jail!


Scott

 

[stan]

another issue to decide on is whether to go with the movie type C-4 brick where its either bare or in a brown cardboard/paper wrapping, or to duplicate US military demolitions charges. did some research and one they use is the M112 demolition charge. its 1.25lbs, and the dimensions are exactly 1-1/16 x 2-1/16 x 11-1/4 (inches). the outside is wrapped in green mylar, and has adhesive strip with a paper backing on the back of the charge for sticking to things.

would be fairly easy to replicate, but not sure that this has the same "movie look" as plain blocks of C-4 would.....

 

[stan]

if anyone can point me to a movie or show that has something along the lines of what i'm doing that would be awesome. i know this is something i've seen before, so if i could do a direct replica of one that would be cooler than a generic type prop.

 

[MooCriket]

Wow...:confused Um, yeah...I think this is cool and all in a twisted sort of way, but Dude! I'm sure someone is watching your thread with great interest, and hopefully we won't be reading about you in any headlines soon such as "Prop Maker Busted For Making Fake C-4, Joke Gone Bad...Lol".

 

[ajones1138]

I really don't think this is a good idea- unless, of course, your goal is to get arrested and thrown in jail. If you do go through with this, just make sure that you NEVER try to go through an airport with it!

 

[exoray]

any input would be welcomed!

Skip the fancy electronics and just gut a cheap cooking timer, and remove the fancy housing exposing the guts...

Keypad, countdown, display all in one already built unit...

http://www.amazon.com/Kitrics-163-Keypad-Timer-Clock/dp/B001DJ1NPS

http://cgi.ebay.com/ws/eBayISAPI.dl...f5ae4e2&itemid=110457382213&ff4=263602_263622

http://www.weatherconnection.com/product.asp?itmky=747432&s=froogle

http://www.bonton.com/product/home/...cales/oxo+good+grips+digital+timer+1061978.do

And do mind your P&Qs to avoid possible legal issues... This is a post 9-11 paranoid world now, getting yourself in stupid legal trouble is easy even when you did nothing wrong...

 

[Toxic]

if anyone can point me to a movie or show that has something along the lines of what i'm doing that would be awesome. i know this is something i've seen before, so if i could do a direct replica of one that would be cooler than a generic type prop.

stargate sg1 used c4 in almost every episode :lol

If I remember correctly season 2 episode 1 has a few nice closeups of c4 bombs with timers

 

[stan]

toxic- thanks for the tip.

here's a few SG1 screencaps I found

 

[stan]

just got a ship notice on the electronics gizmos!

 

[stan]

I really don't think this is a good idea- unless, of course, your goal is to get arrested and thrown in jail. If you do go through with this, just make sure that you NEVER try to go through an airport with it!

with all due respect, i think you're a little off base here. this is nothing worse than an airsoft replica firearm, or any number of replica prop weapons. :angel

obviously going through an airport would be insanely idiotic, as would carrying it around assembled and turned on in the car :eek. i appreciate the concern but don't worry, i think this will be just fine!


i also think the nice thing is that this will be useful information for anyone making a similar type of prop, as the countdown timer display, beeping, and control circuits (and the coding for the microcontroller) will all be easy to re-use for something else.

 

[TallDarkandDisfigured]

I had a similar idea with the clay. It'd be great for special ops in airsoft but I think it's overall a bad thing to have kickin around. :lol All it takes is one peek by some nosey person who doesn't know the difference and you're in serious hot water..

 

[exoray]

with all due respect, i think you're a little off base here. this is nothing worse than an airsoft replica firearm, or any number of replica prop weapons. :angel

Well sometimes life is stranger than fiction, I won't discuss much as the case is ongoing but lets just say false accusations coupled with ignorant overzealous police that took the claims of a delusional 'tipster' hook line and sinker and thought they had the next uni-bomber, can be a legal headache even if the item(s) are a bona fide replicas and legal toys...

Never under estimate stupid people and the grief they can cause you, it does happen...

 

[exoray]

All it takes is one peek by some nosey person who doesn't know the difference and you're in serious hot water..

Exactly... Trust me when I say that if the police believe a tip that you are making bombs/explosives/machine guns (or whatever) they won't send Barney Fife over to to investigate, rather in this post 9-11 society they get search warrants and show up with machine guns drawn and the legal mess begins...

 

[eltee]

Just put an old, unused cell phone by it, some wires and a piece of brass or aluminum small diameter tubing stuck into the explosive compound. The phone is the detonator (very popular in the real world) wires lead into the fake primer (3/8 or 1/4 dia) tube sealed off with some black silicone seal. Would fool most upon first glance.

 

[tk5378]

The C4 I've messed around with comes wrapped in a wax-paper type wrapper which is slick on the inside and matte finish on the outside, and is light brown in color. The clay you are talking about using should be fine for emmualting the real deal, though real C4 is somewhat more brittle.

 

[RPGnerd]

Theres no legality problem if it's just in ones prop room. There are some images in the paper props section for c4.