Tesla Gun Will Probably Kill Something, Sometime

After reading The Five Fists of Science, a retelling of ‘war of the currents’ between [Tesla] and [Edison], [Rob] knew he needed a Tesla gun, the sidearm of the story’s protagonist. Since nothing as stupidly awesome and dangerous as a portable Tesla coil has ever been made, [Rob] needed to make his own.

[Rob] started his build as any good weird weapon build begins: taking apart a Nerf gun. A new Aluminum sand cast body replaced the wimpy plastic body of the Nerf gun and after a few days on a mill, [Rob] had an aluminum Nerf gun perfect for holding the guts of a Tesla coil. The high voltage switch is made of porcelain, and the power supply is an 18 V cordless drill battery and a flyback transformer potted with silicone in a PVC pipe end cap.

[Rob] really has a remarkable build on his hands here, and certainly something no one else has ever tried before. While he hasn’t fired his gun yet, we’re sure we’ll hear about it on the nightly news when he does.

45 thoughts on “Tesla Gun Will Probably Kill Something, Sometime

      1. Actually, I saw Rob explain this thing at Jigsaw Rennaissance a few months back. He said it threw about 10x the amperage of a taser. It made ~6″ sparks, and hands went over ears throughout the room when he fired it. So, no, not harmless at all.

  1. I didn’t read the article yet but it seems to me that the “gun” will fire in all directions. There needs to be a method of forcing everything forward instead of all directions. And along that thought, electricity is going to want to find it’s own path so he’s going to need a lot of energy to make it go the way he wants.

    1. What if you could ionize the air in front of the tesla gun using a mini air vortex cannon, just prior to firing the tesla coil?

      This is kind of how lightening strikes work, minus the forced vortex. You provide a conductive path through the air…

      1. @Paul, good idea! I guess if you are getting hit with 1 million volts you mights as well be wet as well. If you could get enough current to flow through it the water would vaporize and put on quite a show.

      2. Excellent idea! – Although Tesla had this worked out in 1940. He used compressed air to generate the very High Kv and then (coincidentally) accelerated tungsten particles (through a vacuum gap called a lens) in a stream like a BB machine gun at the carnival. Tada! That’s a patent you’ll never see, though.

        Nowadays one uses pulsed lasers to ionize out a nice path for the HV to follow. If you like tasers, you’ll love these bad boys.

        An interesting side effect is the complementary coronal discharge bruise/burn tattoo the target receives with every trigger squeeze. It’s also the only thing keeping it off the market, but once that gets solved (and the likelihood of instant cataract/optic nerve damage) we should see them available for a variety of enforcement purposes.

        May the odds be ever in your favor. :)

  2. A Faraday cage protects from the secondary arcs. Because they’re high frequency, they don’t penetrate skin far; so no risk of it stopping your heart or affecting other internal organs. And they’re very low current, so they don’t do much damage. Even a direct strike to skin only leaves a surface burn, which will turn into a welt later. If you can control where it hits you, it’s protection enough to cover just that part with metal to spread out the initial point of contact. Cover your fingertips with aluminum foil and you can draw arcs to them all day long.

    The real danger is if a secondary arc strikes the primary and you at the same time, which connects you directly to the 20kV capacitor bank. Nothing low current or high frequency about that. Don’t count on a second chance if that happens. And any flaw in your Faraday cage may mean it fails to protect.

    I have seen other handheld Tesla coils. Not many, though. They are used with a professionally made Faraday suit. Or they operate at low power, with extra physical separation and insulation between primary/secondary to (hopefully) eliminate the possibility of a primary strike.

  3. I disagree with the sensationalism of your post for two reasons.
    Hack-a-day recently posted about /several/ portable tesla coils, including HatCoil: http://www.theinspiration.com/2012/05/live-classical-music-in-the-copenhagen-metro/ and the DIY plasma gun: http://hackaday.com/2007/08/08/diy-plasma-gun/
    Additionally, Tesla Coils aren’t inherently dangerous. I remember my teacher shocking willing students in class with a hand-held tesla coil (that the school bought). Though I admit that I couldn’t tell whether or not a Tesla Coil is dangerous (The load of a human would probably alter the output voltage of a tesla coil), there’s no reason to call any Tesla Coil dangerous.

    I’m also uncertain why hack-a-day seems to be infatuated with safety, usually where it isn’t even a concern.

    Nevertheless, [Rob] is freaking awesome – as is his new Tesla Gun! I’m glad you guys decided to feature him :)

    1. I think they’re concerned with safety because they don’t want to get in trouble when Bob over there in the corner decides that this is a cool project and stops his heart when fiddling with the high voltage parts of the project. Let’s face it, Bob isn’t too bright some times and maybe he followed the “instructions” or maybe he didn’t. Maybe he built it bigger. When he’s dead all that anyone will know is that HAD said, “here look a this. Isn’t it cool! You can build your own.” If they tell everyone it’s dangerous then at least Bob will know he might not want to try it on his own. And then HAD can say, “look, we told him it wasn’t safe.

      my $0.02 anyway.

      1. They suddenly became “concerned” with safety ever since they posted regarding the negativity of commenters, and demanded a change.

        I think they’re now trying to point out any safety issues themselves, so that others are less inclined to do so.

    2. It’s extremely weird concerning safety and commentors on HaD.

      If I put up a post about a hand held tesla coil, people complain I’m too focused on safety.

      If I put up a post where someone uses PVC pipe as a potato cannon, people start chewing me out saying PVC should never be used as a pressure vessel, this post is stupid and dangerous and it’s going to kill somebody and probably maim several children and cute animals.

      You can see there’s no way for me to win here.

      1. LOL, yep. Just look at it as a license to write whatever you want, since no matter what, someone will disagree. :)

        Besides, some of the post titles, while perhaps sensational, have brought me a chuckle.

      2. We’ve had similar problems over at instructables. Namely, ‘safety trolls’ (who wouldn’t even contribute to the community) thought it was a good idea to find every instructable that could be potentially dangerous and chew the author out for not mentioning safety. The way I’bles handled it was to ignore/remove the comments if they were unreasonable, and they added a clause in their legal terms of agreement about risk and liability.

        Eventually, the problem sort of went away. ::Shrug::.

  4. @ fightcube
    the vortex is a bad carrier for ions since the rings themselves are fairly stable and don’t lose that much of the gasses that make them up. I beleive the groups that get DARPA funding for solving this type of problem use UV lasers to ionize the air before the weapon is triggered. But as was said before, the equipment needed to get the concept to work as advertized isn’t man-portable yet.
    @ Chris J
    it’s a custom coat someone made for him according to his blog. I’ve seen similar styled coats worn by professional chefs so you could probably find a pattern or buy one at a restaraunt supply store.

    1. That’s not white noise – that’s the rotary converter that she decided to use to get the +400V for the input. Her previous designs used a solid state converter, but there’s a certain charm to a screaming dynamo.

    2. Yep – As The Jenni says, I went with the permanently lubed transmission in the Ryobi 18V circular saw driving an IBM 600W brushless blower motor designed to run on a 350VDC link. It’s menacing and while a 1.4kW 18V to 360VDC converter the size of 2 decks of playing cards is cool and all – it’s just not scary until you see it kill something and even then they just fall over and stop moving. The hell with that.

      The Tesla Bagpipes are coming along swimmingly. 2 drones and a chanter I will play with a piano key tie. Always the piano key tie! So MUGATU! Now to decide if I use OpenCV on a RasPi and camera to read keys or just do something more tactile. Probably switches give a better response, but using capacitive touch is tricky. Turns out you have to gate off your scanning of key pushes while firing and allow a 2-10msec analog pipeline settling time. Ain’t nobody got time for that!

  5. SO, all of you who are saying that Tesla Coils are virtually harmless are completely joking yourselves. A Tesla Coil like the one that he uses can probably throw more than 75,000 volts. At that point, even a tiny amperage doesn’t change the fact that you will get SERIOUS RF burns if the spark touches your skin. Comparing this to a handheld tesla coil from high school is a very dangerous thing to do. RF burns are extremely painful, and dont really heal very quickly. So, dont go telling people that this isn’t dangerous. The capacitor bank alone could kill you twice over.

    1. In theory – yes, an auto tuning 500W RF plasma generator is a burn hazard. God if there be one must love fools, because I’ve never in 20 years seen a single “bad” RF burn from a Tesla coil. Even direct hits from 2kW coils discharging 5 feet repeatedly has not caused subcutaneous RF burns in test victims. Biggest hazards in the system are the primary tank components. People tend to run them with no insulation to facilitate crude tuning and never cover up the LC tank that rings up to 1000+V and several hundred Amps. Being burned by 13.56MHz PAs in the 20-50W range has always hurt much worse. Those burns took weeks to heal from the inside out where the arc went in the finger and exited the elbow to my chair. I have always searched the web and rarely if ever even hear anecdotal accounts of Tesla coil injuries. Only once from a Tesla secondary strike on a 9KVA system using an electric dryer heater coil limited pole pig when I was a member of the mail order organization “The Tesla Coil Builders of America”. It was allegedly a fatal incident but nobody knew the British man allegedly killed. Even with multi hundred joule arc events over hundreds of RF cycles so little of the energy is absorbed by the human. Not saying it’s safe, but respect and confidence in the absence of complacency are more than enough. Approaching any high voltage system with fear and apprehension is a recipe to get killed.

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