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50K Ft/Lbs explosive pile driver

  1. Jul 20, 2007 #1
    A little or maybe its a lot, HELP! How do I go about getting the info to design a "cannon" probably black powder to shoot a 100 lb steel slug into the ground impacting between 20,0000 to 50,000 Ft / Lbs energy? I am a machinist and know how to implement the parts. I dont know where to start regarding the quantity of black powder say ffg grade or maybe a different charge? Ideally I would like to get up to the 50,000 lb mark. The 100 lb steel slug would be about a foot off the ground on rails and held to the Barrel with a 150 lb pressure release mechanism. Thanks in advance. Marc aka Groundtester
    :uhh:
     
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  3. Jul 20, 2007 #2

    berkeman

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    Isn't something like that used in oil exploration and geological underground structure mapping? Have you googled to try to find information about those test setups? Is that what you are trying to set up?

    I don't think we have many explosives experts here on the PF, and even if we did, I doubt the Mentors would allow much in the way of explicit details of explosives construction and use to stay posted. That's a specialized subject with some unfortunate side uses that we would not want to be helping to promote experimentation with, if you understand what I mean.
     
  4. Jul 20, 2007 #3

    Danger

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    I also will not get into much detail here, but I would seriously recommend against using black powder. It's unstable, and is ranked as a high rather than low explosive. Most propellant charges are nitrocellulose based, with grain structure and size tailored to the intended purpose. Here are a couple of commercial links that you can approach about your needs (if the Mods allow them to remain).
    << links removed by berkeman >>
     
    Last edited by a moderator: Jul 20, 2007
  5. Jul 20, 2007 #4

    berkeman

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    I'd prefer not to leave the links in the open forum, so I PM'ed the OP with your links, Danger. I know you're pretty careful with explosives, but I'm not too sure about the OP yet o:)
     
  6. Jul 20, 2007 #5

    Danger

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    Good call. :approve:
     
  7. Jul 22, 2007 #6
    I appreciate all your replys and yes the links are gone. I for sure understand being carefull with any explosive info. I am a government contractor (machine shop projects) and in the process of getting ATF licensed for this project. I dont want to post my cage number in this situation at this time. Of course you shouldnt beleive me either, right. Ok I will check out the oil exploration advise. As far as black powder.... ffg grade or black powder substitutes as Pyrodex are used all the time in Cannon Projectile Shoots for legitamate clubs and civil war reenactments. Again thanks for your time.
    Marc
    PS: also hold HAM Lic. KC8*** wish I had more time to use it.
     
  8. Jul 22, 2007 #7

    Bystander

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    50k ft-lb? 65-70 kJ, and explosives release 4-5 kJ/g. Partitioning of the energy released among noise, heating of barrel and surroundings, and actual mechanical work done on a projectile? If you call efficiency the ratio of mechanical energy to total release, it ranges from 0.3 - 0.5 as you move from small arms to 16" naval rifles. 30-50 g, which you can compare to the 4.5 g in a .45-70.
     
  9. Jul 22, 2007 #8
    the best idea would probably be to take a look at a textbook on cannon's or a cheat sheet type of thing which would tell you how to construct the barrel dependant on the amount of explosive used, if following bystander's advice you made a cannon capable of using 50 grams of explosive, than you can be guaranteed to have a device capable of meeting your requirements.

    out of curiosity what is the cannon going to be used for?
     
  10. Jul 23, 2007 #9

    Danger

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    Since I'm not a Yank, I have no issues about what your motives are for wanting this; I take you at your word regarding the end purpose. I'm quite sure that if you were a terrorist, you wouldn't be asking such a rudimentary question here; you'd have far better nefarious sources. Nonetheless, I don't want to read about you blowing yourself up because of messing with stuff that you don't understand.
    That having been said, if you are indeed a government contractor, you should have access to any number of explosives experts courtesy of that same government. You can call upon bomb squads, Special Forces teams from any branch of the military, or a tonne of CIA bagmen.
     
  11. Jul 23, 2007 #10
    Thanks again to all. are we talking about the same grams? Because 50 grams or about 2 oz. = about 875 grains black powder. That amount is the standard load for a small 2 inch Barrel by about 14" long to shoot a 10 oz ball about 800 yards when the barrel is at a 45 degree angle. As far as a Gov contractor calling on resources...only related to on their job and even then they subed it out due to their lack of resouces to begin with. I contacted the ATF but their info was limited to shock waves caused by certain amonts of ANFO. As far as getting blown up I appreciate your concern and every caution is taken. I do have a fair amount of experience with known guidelines for chamber size, steel type, wall thickness etc relative to the amount of black powder charge. I dont have any idea though of whats going on Force wise. I am going to the phone book tomorrow and will call some engineers and see where that leads. The device is for a long time customer in the mining business.
    This is a brain teaser for me????
    Thanks, Marc
    PS: As far as an up to no good "person" unfortunatley there is way to much on the net and its not on this site anyway.
     
  12. Jul 23, 2007 #11

    Danger

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    I would recommend contacting CIL, then. The copy of their "Blaster's Handbook" that I have is over 30 years old, but chock full of info about all kinds of neat stuff. It's pretty much geared toward mining, but incudes stuff for more 'civilian' endeavours such as bridge-building.
     
  13. Jul 23, 2007 #12

    Bystander

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    Yup.

    Sounds 'bout right.

    Energy -wise, or "force-wise?" The energy we've covered --- force comes in if you're looking at "burn rates" of black powder vs. nitrocellulose propellants; black powder "deflagrates" at ca. 500 m/s, and the reaction is all over soon's the "match" hits the touchhole (max barrel length to improve efficiency and range is 12' or so, depending on what source you choose). You sound like a blackpowder junkie --- ever played with black powder loads vs. modern propellants in late 19th century pieces? a la a Model 94 .32-40 or .38-55? Give you a feeling for "force" --- BP loads are NOT comfortable. 'Magine that's the attraction in seismic work --- nice sharp wave front.

     
  14. Jul 29, 2007 #13
    Ok, I give up on doing my own figuring, past my scope, past the yellow pages scope. Does anyone know an engineer or someone I can pay to work the math or whatever it takes to do? Thanks, you can e-mail me please.
     
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