Coilgun Blueprints




About: Changing my profile around, and planning on posting some more instructables. Be ready.

This is a relatively simple coilgun me and my grandpa made this summer. I will show you how to make a similar one. Please add a comment if you need extra help with anything. Also, add a comment if I need to change any of the steps.Please rate and comment, andplease help me if i'm not clear on something. It takes about 1:30 to 2:00 minutes to charge.  Have fun!

-around 90 feet of magnet coil
-2 1.5 inch plexiglass washers for winding coil
-1 camera charging circuit (KODAK)
-1 on/off switch
-1 40 amp or higher toggle switch for trigger
-1 D battery holder
-1 capacitor around 450 volts and 1500 MicroFarads
-1 toy gun large enough to mount the circuits in
-1 carbon arrow shaft
-you may need other materials according to the gun apparatus you use

-soldering iron with solder
-screw driver (to take the gun apart)
-a hand saw (to cut barrel to appropriate length)
-glue or drill and screws to mount circuits

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Step 1: Wind the Coil

Wind the coil as well as you can around a axle a little bit bigger than the barrel. Fasten the washers around the axle for support. You may use you hands, but my grandpa and I made a little rig to make it easier. Wind it 2.5 inches in length, with 10 layers of coil.

Note: Before you go to the next step, you may want to rig a testing circuit to make sure the coil fires.

Step 2: Barrel and Projectiles

Find the length that the barrel should be in your gun and cut it to the correct length. Find the projectile your are going to use, most likely a nail with a grounded down head, and position the coil so when the projectile end is at the very end off the barrel, the tip of the projectile is at the very begining of the coil. Last, put a stopper on the end of the barrel so that you may slide the projecile from the tip of the barrel.

Step 3: Placing the Components

Now it is time to start laying out the circuits. Figure out where you want to lay the components. Make sure they will fit in the spots you want to lay them. DON'T FASTEN THE PARTS YET, find out how much wire you need to connect the components first, then add an inch to make sure the wire will reach.

Step 4: Soldering the Components Together

The title says it all. Solder the componets together using this schematics below. Notice there is no relay. We tried a gun with a relay, put after a few shots, it nedded to be replaced. Since we are using a switch that cuts the battery on to make the circuit start charging, we need to solder a bare piece of wire to the switch on the circuit.

Step 5: Finishing Touches and Testing

Before you close up the gun, you may want/need to add some finishing touches. Here are a few of the ones we did:
-a lens from the camera to make the LED from the circuit appear larger when the capacitors charged
-a cover to go over the big, bare spot on the top of our gun
-a projectile holder
-test prongs to make sure the gun was charging (recommended)

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    79 Discussions


    5 years ago on Step 5

    1500 micro farads is plenty. That's roughly the same as 10+ average camera flash capacitors in parallel.
    And at 450v, holds about 150 joules of energy.
    Eneergcam, you could try do a simple switch using an SCR or MOSFET , just check its voltage and current ratings. They should be able to handle the current that killed the relay.

    1 reply

    Reply 1 year ago

    If you can bump it up to about 460 joules of energy, you could propel a 10 gram projectile about 1000fps.


    1 year ago

    would a 500F 2.7v capacitor bank be good for a single stage coil gun?


    9 years ago on Introduction

    man, only one KODAK sircuit? it would take ages to charge that capaitor, i used 7 to charge two capacitors 250V@1000uF and they are cherged at around 10sec. one 250V@1000uF takes 1min to be charged by one KODAK sircuit, my opinion is that you should use at least five sircuits.

    4 replies

    Reply 8 years ago on Introduction

    how exactly do you wre several circuits tigether? if you could post a link to an instructable or tell me that would be awsome.


    Reply 9 years ago on Introduction

     we decided just to have one for our first gun, and we didnt know where we could put them, but maybe one day ill make one with a few more circuits


    7 years ago on Introduction

    would you be able to add a sensor or something that when the projectile passes by it shuts off the magnet, that way you could increase the efficiency and make it stop dead center

    1 reply

    Reply 7 years ago on Introduction

    hmm thats an interesting concept, my coil gun making days are over but maybe you could look into adding a reed switch or something of that nature into the circuit


    8 years ago on Step 5

    hmm, i suppose that i wasn't very powerful since it only had one capacitor. You
    might want to add a couple more of those, say at least 4 of the same caps.And get a better switching device like an scr.

    3 replies

    Reply 8 years ago on Introduction

    but you said to somebody that the capacitor is small and now your saying its big makes no sense.BIG or small.


    Reply 8 years ago on Introduction

    Its all relative, compared to the camera circuit capacitors if very large, but compared to other larger ones, its small.


    9 years ago on Step 4

    when i vas "studying" about coilguns for making one, i read something about if you conect a capacitor to a coil, it generates AC, and inverted voltages can damage the electrolythic capacitors, does it realy happen?, did you add something to avoid it?, is it just too small to be considered?
    (yes, my ortography is realy bad, but i'm not native english speaker)

    1 reply

    Reply 9 years ago on Step 4

    I dont now where you read that, but you dont need to add anything, the voltage is probably too small, and the capacitors are also very small.