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  1. Member Since
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    Apr 21, 2010, 2:04 PM - Dummy C-4 bomb - General prop #1

    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.

  2. Node Nine's Avatar
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    Apr 21, 2010, 2:08 PM - Re: Dummy C-4 bomb - General prop #2

    I think that is damn cool and have thought about doing it myself but be careful about taking it out in public
  3. Member Since
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    Apr 21, 2010, 2:10 PM - Re: Dummy C-4 bomb - General prop #3

    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!
  4. Member Since
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    Apr 21, 2010, 2:11 PM - Re: Dummy C-4 bomb - General prop #4

    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.
  5. RPF Premium Member Skaught's Avatar
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    Apr 21, 2010, 2:14 PM - Re: Dummy C-4 bomb - General prop #5

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


    Scott
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    Apr 21, 2010, 2:17 PM - Re: Dummy C-4 bomb - General prop #6

    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.....





  7. Member Since
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    Apr 21, 2010, 2:21 PM - Re: Dummy C-4 bomb - General prop #7

    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.
  8. MooCriket's Avatar
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    Apr 21, 2010, 3:08 PM - Re: Dummy C-4 bomb - General prop #8

    Wow... 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".
  9. ajones1138 is offline ajones1138
    Apr 21, 2010, 3:15 PM - Re: Dummy C-4 bomb - General prop #9

    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!
  10. exoray's Avatar
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    Apr 21, 2010, 3:21 PM - Re: Dummy C-4 bomb - General prop #10

    stan said: View Post
    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-Ke.../dp/B001DJ1NPS

    http://cgi.ebay.com/ws/eBayISAPI.dll...=263602_263622

    http://www.weatherconnection.com/pro...7432&s=froogle

    http://www.bonton.com/product/home/k...mer+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...
  11. RPF Premium Member
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    Apr 21, 2010, 3:25 PM - Re: Dummy C-4 bomb - General prop #11

    stan said: View Post
    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

    If I remember correctly season 2 episode 1 has a few nice closeups of c4 bombs with timers
  12. Member Since
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    Apr 21, 2010, 4:05 PM - Re: Dummy C-4 bomb - General prop #12

    toxic- thanks for the tip.

    here's a few SG1 screencaps I found





  13. Member Since
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    Apr 21, 2010, 5:20 PM - Re: Dummy C-4 bomb - General prop #13

    just got a ship notice on the electronics gizmos!
  14. Member Since
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    Apr 21, 2010, 5:23 PM - Re: Dummy C-4 bomb - General prop #14

    ajones1138 said: View Post
    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.

    obviously going through an airport would be insanely idiotic, as would carrying it around assembled and turned on in the car . 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.
  15. TallDarkandDisfigured's Avatar
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    Apr 21, 2010, 6:16 PM - Re: Dummy C-4 bomb - General prop #15

    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. All it takes is one peek by some nosey person who doesn't know the difference and you're in serious hot water..
  16. exoray's Avatar
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    Apr 21, 2010, 6:17 PM - Re: Dummy C-4 bomb - General prop #16

    stan said: View Post
    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.
    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...
  17. exoray's Avatar
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    Apr 21, 2010, 6:21 PM - Re: Dummy C-4 bomb - General prop #17

    TallDarkandDisfigured said: View Post
    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...
  18. eltee's Avatar
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    Apr 21, 2010, 6:24 PM - Re: Dummy C-4 bomb - General prop #18

    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.
  19. tk5378's Avatar
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    Apr 22, 2010, 12:01 PM - Re: Dummy C-4 bomb - General prop #19

    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.
  20. Member Since
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    Northwestern USA
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    Apr 23, 2010, 4:11 AM - Re: Dummy C-4 bomb - General prop #20

    Theres no legality problem if it's just in ones prop room. There are some images in the paper props section for c4.
  21. Architect's Avatar
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    Apr 23, 2010, 4:31 AM - Re: Dummy C-4 bomb - General prop #21

    I think the real issue will be if you tote it around and do not clearly mark it as a movie prop or some such. Kinda like printing money, if you clearly mark it in a way that can not be removed and is easy for anyone in the real world to see, nothing else matters, and with watermarking in photo software you can make it near impossible for a camera to see, at least from a scene point of view. obviously a shot directed at it will reveal it for what it is but who would do such a thing to their own movie right?
  22. Maelstrom's Avatar
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    Apr 23, 2010, 7:08 PM - Re: Dummy C-4 bomb - General prop #22

    Best form of "C4/plastic explosives" shown in any movie and requires no fancy doodads except for wires...

  23. Member Since
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    Apr 25, 2010, 2:10 AM - Re: Dummy C-4 bomb - General prop #23

    got the arduino in and have a test program / rough wiring together. got it counting down on a 4 digit 7 segment display!

    http://www.youtube.com/watch?v=cWnbAP-wRh8
  24. DaddyfromNaboo's Avatar
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    Apr 25, 2010, 2:23 AM - Re: Dummy C-4 bomb - General prop #24

    Hi folks,

    I just went through your thread again, and I have to express my concern.

    While it of course is a valid question to make something generic that could be used in a movie it is not cool to try and replicate the REAL deal of C-4.

    It is very common in the movie business to make something up, especially weapons of mass destruction.

    There are professional prop makers on high profile productions that got into trouble because their designs looked too real.
    Of course we do not want to get hobbyists into trouble because their research was too thorough.
    The trouble starts if you use the name of a manufacturer on a replica.

    If you want to make a replica, then use the reference on props that is available in movies or tv show and come up with a creative design.

    In this case here requesting and posting information on how the real deal looks is not wanted and fully unnecessary.

    Regards,
    Michael
    RPF staff








  25. RPF Premium Member Grey's Avatar
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    Apr 25, 2010, 6:00 AM - Re: Dummy C-4 bomb - General prop #25

    It's kind of funny that people are freaking out and assuming this guy is going to go carrying around a bunch of fake C4 in public, or take it to airports????? who would EVER do that.

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