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Thread: Building a railgun or coilgun/guass gun

  1. #1 Building a railgun or coilgun/guass gun 
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    I'm thinking about trying to build one of these.

    1) What am I getting into?

    2) Which would be easier, railgun or coil/gauss gun?

    3) I'm really rusty on the physics behind these, so what's some good online material I can use to freshen up.

    4) How expensive would this be?

    I know this is really broad but basically some backround information about railguns and how I should go about this would be nice.

    Thanks


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  3. #2  
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    My friend was telling me that they have a type of gauss gun. It's used to launch harpoons for whale hunting. I don't know how accurate that is, but try doing a search.


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  4. #3  
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    1. High powered, complex electronics with importance placed on timing, power, and magnetic fields.

    2. Rail Gun

    3. F = mA , A=dV/dt, V=dx/dt That's all of your physics, I just saved you a lot of time. Unless you're talking about calculating the magnetic field, but I think that's not something you should be trying to do unless you absolutely need to build to specifications. Otherwise you can do that stuff experimentally.

    4. Very. You need a microcontroller or some timer devices to fire the magnets in the correct order at the correct time. You also need to build a smooth tube for the projectile guide, the electromagnet coils, a power supply capable of creating a large force from the magnets, and a supporting structure to hold it all.

    Overall, if you don't have any electronics or mechanical training, this will take a long time, a large amount of money, a lot of testing, and will be large and unwieldly.
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  5. #4  
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    Railguns are relatively simpler by design than a coil or Gauss gun.

    By simple, I mean its 2 rails with a massive power supply and an armature to connect the rails the circuit. That's it in it's most simple form
    Wise men speak because they have something to say; Fools, because they have to say something.
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  6. #5  
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    A guy I know some years ago claimed he made an ion cannon. He said it didn't have much range, but it peeled the paint off a car. Instead of accelerating a mass, he charged argon in a pressurized chamber filled with steel wool. He synchronized the release of gas with the magnet drivers.

    I myself wonder if he really did it, but it's plausible.
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  7. #6  
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    What is the purpose of the steel wool?

    I'm calling that ion cannon BS until proof surfaces for these reasons:

    1. The steel wool seems to have no purpose. It would seem he put it in there to imply that he was rubbing the argon.

    2. Argon is a noble gas that requires 1500+ kJ of energy to ionize.

    3. I don't think it would strip paint. The likely result of charged Argon smashing into things at such low speeds would be like a strong gust of wind. Unless ionized argon reacted with the target, it is very likely the only damaging thing it could do is asphyxiate people in enclosed spaces.
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  8. #7  
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    Quote Originally Posted by alienmindsinc
    What is the purpose of the steel wool?

    I'm calling that ion cannon BS until proof surfaces for these reasons:

    1. The steel wool seems to have no purpose. It would seem he put it in there to imply that he was rubbing the argon.

    2. Argon is a noble gas that requires 1500+ kJ of energy to ionize.

    3. I don't think it would strip paint. The likely result of charged Argon smashing into things at such low speeds would be like a strong gust of wind. Unless ionized argon reacted with the target, it is very likely the only damaging thing it could do is asphyxiate people in enclosed spaces.
    I have a hard time getting past some of it myself, but it could be true.

    1) The steel wool was for larger surface area to the gas to strip the electrons.

    2) Yes, Argon is a noble gas. Would you want to use a reactive gas?

    3) That's why it had a short range. It was slowed rapidly by the air. Discharge of ionization would be a larger problem.
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  9. #8  
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    1. Steel wool, if it worked, would not create nearly enough energy to ionize Argon. It's not like rubbing a balloon with felt.

    2. The point of my pointing out Argon as a noble gas is that Argon, though easy to come by, and relatively cheap, has a very high ionization energy. Something high enough that I would consider the energy requirements prohibitive. Therefore, I consider it unlikely that a hobbyist would be able to do such a thing. Using a reactive gas may be a better choice, if you are a chemist and know what you are doing.

    3. I doubt the power of any "gas" powered item described in this manner. Without some projectile, how is the air supposed to rip up the surface enough to get under it and rip away the paint?

    While I normally champion the "could be true" mentality, I think someone was exaggerating greatly. The reasons I've given are why I've come to this conclusion. If someone can prove me wrong, by showing me a decent design that incorporates your friend's elements, I will gladly admit my folly.
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  10. #9  
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    Quote Originally Posted by alienmindsinc
    1. Steel wool, if it worked, would not create nearly enough energy to ionize Argon. It's not like rubbing a balloon with felt.
    Are you saying that a few hundred kvolts isn't enough? The steel woll was only for surface area contact of the charging voltage. Rubbing a balloon... Please, don't make me laugh. We are not talking about static charges, but real electrical charges. Real power.

    Now I am ignorant here in one aspect. How much voltage would it take to ionize argon? I am assuming that some good HV multipliers or transformers can do it.
    Quote Originally Posted by alienmindsinc
    2. The point of my pointing out Argon as a noble gas is that Argon, though easy to come by, and relatively cheap, has a very high ionization energy. Something high enough that I would consider the energy requirements prohibitive. Therefore, I consider it unlikely that a hobbyist would be able to do such a thing. Using a reactive gas may be a better choice, if you are a chemist and know what you are doing.
    Well, he was a pretty smart geek, and I know what a noble gas is. I don't know what his resources were, but you are automatically assuming average. I would say no way a typical hobbyists could do it also. I simply don't see it prohibitive. 1520.6 kJ per mol for the first ionization. It's not a tremendous amount of power.
    Quote Originally Posted by alienmindsinc
    3. I doubt the power of any "gas" powered item described in this manner. Without some projectile, how is the air supposed to rip up the surface enough to get under it and rip away the paint?
    I think he was likely full of BS myself, but I don't see anything prohibitive about it. The way he described it those years ago made sense.

    I'm beginning to think you haven' a clue what you are talking about. We are not talking about air ripping anything up, but the charged ions. Yes, it takes a relatively large amount of power to do that. Far from prohibitive though.
    Quote Originally Posted by alienmindsinc
    While I normally champion the "could be true" mentality, I think someone was exaggerating greatly. The reasons I've given are why I've come to this conclusion. If someone can prove me wrong, by showing me a decent design that incorporates your friend's elements, I will gladly admit my folly.
    We are talking years ago about someone who I lost contact with. Just because you cannot imagine it, doesn't mean it doesn't exist. Guess you have a hard time thinking outside the box. It see it as rather difficult, but far from impossible.
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  11. #10  
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    Yes, I am saying that a few hundred kilovolts isn't enough. I suppose you could try to do it with a few hundred kilovolts, but that would mean you need a few hundred amps as well. The ionization energy is just over 1500 kJ, as you said. that's 1500 kW-s. IE: You would use 1500 kW for an entire second to ionize argon. I know of no hobbyist supply capable of being both mobile and safe enough to create this ion cannon and move it to a car to strip paint with. If the supply worked, the power bill would be prohibitive.

    As for the steel wool, that makes much more sense than what I thought he was doing with it. It seemed to me like a silly fantasy of using steel wool cause friction via passing a compressed gas over it, which is a major factor in why I thought he was full of BS. The steel wool for more surface area seems rather inventive.

    Finally, your example was about removing paint from a car. In order to remove the paint you need to somehow get the paint to stop sticking. That involves either manual (mechanical) manipulation, as you suggest the ion cannon used, chemical reaction (which you implied it did not use), or some other means that is a hybrid of both. My question was half rhetorical, half serious. How is a steady stream of ionized gas going to remove paint from a vehicle? I don't think it can, logically speaking, it seems as if it would have the same effect as sitting the car in a wind tunnel. Ions are not some magical particle with special properties that can do special things.
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  12. #11  
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    Quote Originally Posted by alienmindsinc
    Yes, I am saying that a few hundred kilovolts isn't enough. I suppose you could try to do it with a few hundred kilovolts, but that would mean you need a few hundred amps as well. The ionization energy is just over 1500 kJ, as you said. that's 1500 kW-s. IE: You would use 1500 kW for an entire second to ionize argon. I know of no hobbyist supply capable of being both mobile and safe enough to create this ion cannon and move it to a car to strip paint with. If the supply worked, the power bill would be prohibitive.
    First off, we aren't talking about needing a mole of gas in the charging chamber, ionizing all of it, or any specified charging time. It does look impractical from a storage point of view. I like to keep an open mind. Don't you?

    As for mobility, I recall he said he had a power cable coming to it. It was not portable.
    Quote Originally Posted by alienmindsinc
    Finally, your example was about removing paint from a car. In order to remove the paint you need to somehow get the paint to stop sticking. That involves either manual (mechanical) manipulation, as you suggest the ion cannon used, chemical reaction (which you implied it did not use), or some other means that is a hybrid of both. My question was half rhetorical, half serious. How is a steady stream of ionized gas going to remove paint from a vehicle? I don't think it can, logically speaking, it seems as if it would have the same effect as sitting the car in a wind tunnel. Ions are not some magical particle with special properties that can do special things.
    I pretty sure it would be from the heat of the charged ions hitting the surface, and reacting that way. It was a short burst of gas, propelled with alternating coils and magnets.

    I only see three problems with such a thing. First off, I cannot image a burst of gaseous ions in an atmosphere. I think it's about as effective as shooting a high velocity rifle into the water. The round disintegrates. My second problem is that the charged gas would tend to repel itself. To make such a think work, I think you would have to be inches from the target, at least under a yard. Then as I earlier mentioned, actually charging a small volume of compressed gas with enough energy. There would be some pretty large repelling forces, making it difficult. The voltage can be dealt with using good insulation, but one wrong move could produce a deadly shock.
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  13. #12  
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    I still have problems with the energy required. I think it would trip almost all household breakers. If you upped the V to the point where you could safely do it at home you'd be way above the breakdown voltage of air, causing arcs away from the setup and to nearby creations.
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  14. #13  
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    Quote Originally Posted by alienmindsinc
    I still have problems with the energy required. I think it would trip almost all household breakers. If you upped the V to the point where you could safely do it at home you'd be way above the breakdown voltage of air, causing arcs away from the setup and to nearby creations.
    I'm done with you. You ignore so many facts and solutions, and jump to unfounded conclusion. Repeatedly. Breakdown in air is about 30,000 volts per inch, but the argon charging chamber isn't in air. It would be well insulated in a good dielectric. Do you know what dielectrics are? Trust me, anyone who is knowledgeable enough to attempt this, will use good insulation techniques.
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  15. #14  
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    Quote Originally Posted by Arcane_Mathematician
    Railguns are relatively simpler by design than a coil or Gauss gun.

    By simple, I mean its 2 rails with a massive power supply and an armature to connect the rails the circuit. That's it in it's most simple form
    Coil guns are far, far easier to make than rail guns. Rail guns require much large, more dangerous power sources, and most home-built rail guns end up with the projectile either arc-welded to the rails or melted by resistance heating before it even leaves the gun. Rail guns might seem simpler in theory, but they are far harder to actually make work. On the other hand, many people have demonstrated working coil guns, many with very limited budgets.
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  16. #15  
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    Quote Originally Posted by alienmindsinc
    Yes, I am saying that a few hundred kilovolts isn't enough. I suppose you could try to do it with a few hundred kilovolts, but that would mean you need a few hundred amps as well. The ionization energy is just over 1500 kJ, as you said. that's 1500 kW-s.

    IE: You would use 1500 kW for an entire second to ionize argon.
    The energy needed would depend on how much argon you wanted to ionize. The ionization energy of an argon atom is about 16 electron volts, or 2.6*10^-18 joules. 1500 kJ is the energy needed to ionize 40 grams of argon. You would would only need a 1500 KW power source is you were planning to ionize 40 grams of argon per second. I would assume that a homemade "ion gun" would ionize waaaaaaay less argon than that. You can ionize argon using a AA battery if you want to - you just won't be ionizing a lot of it.
    Finally, your example was about removing paint from a car. In order to remove the paint you need to somehow get the paint to stop sticking. That involves either manual (mechanical) manipulation, as you suggest the ion cannon used, chemical reaction (which you implied it did not use), or some other means that is a hybrid of both. My question was half rhetorical, half serious. How is a steady stream of ionized gas going to remove paint from a vehicle?
    If the argon was being ionized by high voltage, it would come out very hot. Most likely it would work like any other high-temperature paint stripping gun (which people use to remove paint from things all the time). The only different would be that it had a really unusual heat source.
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  17. #16  
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    Quote Originally Posted by Scifor Refugee
    Quote Originally Posted by alienmindsinc
    Yes, I am saying that a few hundred kilovolts isn't enough. I suppose you could try to do it with a few hundred kilovolts, but that would mean you need a few hundred amps as well. The ionization energy is just over 1500 kJ, as you said. that's 1500 kW-s.

    IE: You would use 1500 kW for an entire second to ionize argon.
    The energy needed would depend on how much argon you wanted to ionize. The ionization energy of an argon atom is about 16 electron volts, or 2.6*10^-18 joules. 1500 kJ is the energy needed to ionize 40 grams of argon. You would would only need a 1500 KW power source is you were planning to ionize 40 grams of argon per second. I would assume that a homemade "ion gun" would ionize waaaaaaay less argon than that. You can ionize argon using a AA battery if you want to - you just won't be ionizing a lot of it.
    Finally, your example was about removing paint from a car. In order to remove the paint you need to somehow get the paint to stop sticking. That involves either manual (mechanical) manipulation, as you suggest the ion cannon used, chemical reaction (which you implied it did not use), or some other means that is a hybrid of both. My question was half rhetorical, half serious. How is a steady stream of ionized gas going to remove paint from a vehicle?
    If the argon was being ionized by high voltage, it would come out very hot. Most likely it would work like any other high-temperature paint stripping gun (which people use to remove paint from things all the time). The only different would be that it had a really unusual heat source.
    Thank-you.

    I don't mind discussing reasonable points, but I was getting rather fed up with alienmindsinc.

    You you think there would be a big issue with the charged gas dispersing too much from repulsion and discharge too much operating in an atmosphere?
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  18. #17  
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    What type of rail gun are you talking about, the rail gun I'm thinking about using uranium and has a green streek of energy come out of it's barrel, a coil gun, are you talking about a chain gun?
    the more science you know, the less crap you get.
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  19. #18  
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    There was actually an article by some guy featured in Nuts & Volts (march 08 issue) detailing how to build your own EM coil gun. The basic idea was to use HV capacitors and discharging them into a coil to shoot some steel darts. He got about 100+ ft/s using some fairly basic techniques.
    see his page at http://www.thinkbotics.com/military.htm

    Seems cute enough, but I'm sure you could scale it to be more powerful...
    Multidisciplinary Engineering Services for Individuals, Inventors and Small Business: http://www.solveering.com
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