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Build Your Own EMP Generator(2006)

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This is a thought experiment

I have built toy cannons (and survived). I have also read about military tactical EMP weapons so here is a bit of speculation on how you might create one...No guarantees that it will work of course! It should generate some kind of EMP pulse but how strong depends on many factors. A tranny radio nearby may just go click, or it may fuse out! Certainly no one with a pace maker should try this or be anywhere near when it is attempted!

First Build a Toy Cannon

As a kid I made toy cannons using tobacco tins full of plasticine as a base, a car aerial as the cannon and (safety) match powder as the propellant. It's very easy. Cut 6" of aerial, crimp one end shut and embed that end (do not get the ends wrong!) in the plasticine. Remove the match powder from half a dozen safety matches (if you use non safety they might detonate when compacted- this is generally considered to be a very bad thing). A razor or sharp knife will do. You just want the powder so remove the wood. Insert enough powder to fill maybe an inch in the aerial and gently push it down. A knitting needle makes a good plunger. I suggest you mark the the aerial where the powder is located so you can position the candle correctly.

The picture below shows the match powder in red. The yellow is shrapnel- bits of stone, grit anything that would fit in. Now light a birthday candle stuck in the plasticine under the aerial below where the match powder is and make sure the business end of the cannon (the bit you do NOT want to be in front of) it's pointing out to sea, or at a wall, bank of earth or pile of sand, and not at you or anybody else.

Back off quick, and stand behind something. If the aerial is weak it might shatter and shrapnel is not conducive to good health. It's probably a good idea to do this away from property, people or animals. 6-12 Matches provides enough energy to be deadly or at least make unpleasant holes in humans. After 30 or so secs it should go bang. Do video it (if you can safely) and put it on youtube.

Cannon
Ok, You're probably wondering what a toy cannon has to do with an EMP Generator. Well same principle. Really! It is rumoured (according to New Scientist in 2000) that you can make a portable EMP with just a stick of dynamite, a metal tube, a ferrous rod and a coil of wire. The dynamite detonates in the tube sending the ferrous rod at great velocity through the coil of wire which generates a massive pulse. Now you can see where the toy cannon fits in.

EMP Coil Winding

The EMP coil is the crucial part of the generator. It has to be a closely wound coil, as small in diameter as possible. The diameter depends upon having an available former which is what you wind the coil on. A plastic straw is ideal so long as you have a (ferrous) nail or screw that fits in the tube comfortably (with the flat head sawn or filed off). It should not rattle in the straw, if it does then much of the force of the propellant is going to be wasted. An easy way to test this is to blow it. If you feel the air escaping from the tube without moving the nail then you need a wider nail/screw. get it right and you should be able to blow the nail/screw along the tube. Alternatively you could wrap duck tape round the nail/screw to increase it's diameter.

Take a thin gauge wire and tightly wind this along a 4" section along the straw. Do not overtighten, as this could deform the straw and cause a blow out. Getting the winding tight but not overtight will increase the straw's strength. You can add multiple windings if you have plenty of wire, but ensure that they all run in the same direction- ie when one layer is finished, run it back to the other end and wind from there. The more layers the better. Connect both ends. Sure it will probably fuse or melt but...

Insert the nail/screw in one end of the tube and put in a small stop- a blob of blu tack will do. You just want to hold the nail in place in the tube. This end of the tube will be attached to the propellent tube so that when the cannon is fired, the nail will shoot very rapidly though the coil and generate the pulse.

Propellent Tube

Just like the toy cannon, this is a bit more powerful and will probably need all the power from a box of safety matches. Remember do not use non safety matches as they ignite too easily. An old cigar tube will make a suitable cannon and you will need enough match powder to make at least 1" deep propellant. You might consider however using an electrical firing mechanism as it will take a while for the metal to heat up than the car aerial. Take a long length of thin insulated wire. Fold it in two and remove about 1/4" of insulation from one end. Insert this into the cigar tube so it is at the bottom. The other ends can be attached to a 9v or 12v battery once it's all setup. That should heat the uninsulated wire to ignition temperature.

If you want to be really slick, put the match powder into rice paper or tissue paper and shape it into a cylinder. Insert the bare end of the wire into the powder, checking that the other ends are nowhere near a battery.

Joining the Propellent Tube and Coil

This is the tricky bit. The coil assembly must be firmly attached to the open end of the cigar tube so that it is effectively air tight. All the blast must go up the straw. If the open end of the cigar tube is crushed with pincers then this will be a one off. The straw must only go a short distance into the tube (and none of the coil). If this is not done, then the danger is that when it is fired the entire coil assembly will go flying off into the blue younder, not just the nail/screw.

Let's assume you've built it and joined the two bits correctly. It's almost ready to fire. I suggest you mount it horizontally, facing an earth bank or pile of sand, anything that will absorb and not reflect the nail. If you've done it right, the nail will be a very dangerous high velocity projectile so you need to deal with it. The idea is not to create a BFG. Of course if you lined up a column of balloons, it would make a very videoable spectacle, assuming you didn't fuse the video camera of course! A convenient Faraday cage like a car parked 50' away might make a suitably safe recording platform.

That's It- Light the blue fuse and retire!

The author accepts that this is a gloriously daft and stupid experiment, as was Ben Franklin's "Kite flying in a storm" experiment. Have fun!

Coming Soon- Black Hole generator

Don't hold your breath waiting for this one... <g>

 

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