How to Make a Coilgun

Co-authored by Hunter Rising

Last Updated: May 13, 2021 References

Coil guns may sound like futuristic weapons, but they’re actually something you can build at home. They use a current to charge copper wires and create an electromagnet to launch a projectile. To build a coil gun, all you need are a few tools, some wire, and a disposable camera. When you’re finished, you’ll be able to practice shooting a gun you made all by yourself!

Part 1

Part 1 of 4:

Taking Apart a Camera Circuit

1
Pry a new or used disposable camera apart with a screwdriver. Remove the paper layer from the disposable camera and locate the tabs on the bottom and sides of the casing. Press down on the tabs with the end of a screwdriver, pulling the case apart while they’re loose. Once all the tabs are released, pull the camera case apart.^{[1]
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- If the disposable camera doesn’t have tabs, press into the seam on the side of the camera with a flathead screwdriver to force it apart.
- Ask the photo department at a local drugstore to see if they have used disposable cameras you could use.
2
Take out the camera battery and the circuit board. Put on rubber gloves before you start working with the components inside the camera. Take out the battery first so that there isn’t a current going through the circuit. Slide your screwdriver underneath the circuit board, and carefully pry it out of the camera.^{[2]
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- Don’t use your bare hands to take apart your camera since you could get shocked.
Tip: Save the camera case so you can easily mount the circuit for your coil gun later on.

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3
Discharge the capacitor with an insulated screwdriver. The capacitor looks like a black barrel on your circuit board and it stores energy. Make sure the screwdriver you’re using has a rubber-insulated handle. Touch the terminals on the end of the capacitor with the end of your screwdriver to discharge it. The capacitor may spark and make a loud snapping noise when you discharge it.^{[3]
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- Never touch the terminals on a capacitor with your bare hands since it contains a high voltage.
- Even when you use an insulated screwdriver, wear rubber gloves as an extra layer of protection.
4
Cut the flashbulb off from the circuit. The flashbulb looks like a clear box and has 3 wires running between it and the circuit board. Use a pair of wire cutters to cut the wires near the capacitor to completely disconnect the flashbulb. Throw the bulb away when you’re finished.^{[4]
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Part 2

Part 2 of 4:

Creating the Gun Barrel

1
Take apart a ballpoint pen so you can use the tube. Use a basic ballpoint pen that has a cap for the easiest results. Grab the tip of the pen and try pulling it out or unscrewing it from the tube. Remove the ink chamber from inside the pen so you have an empty tube to use as your coil gun’s barrel.^{[5]
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Tip: Leave one end of the tube closed so your projectile doesn’t fall out when you load it.
2
Wrap 1–2 in (2.5–5.1 cm) of the tube in a single layer of 30-gauge copper wire. Start your coil about ¹⁄₂ in (1.3 cm) from the closed end of pen tube. Make sure the coils are tightly wrapped and don’t overlap. Continue wrapping the wire around the pen until 1–2 in (2.5–5.1 cm) are covered with the wire.^{[6]
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- The copper wire may also be called magnet wire when you buy it from a hardware store.
- Don’t cut the wire when you’re finished with the first layer since you’ll use it to make additional layers later on.
3
Place a layer of electrical tape over the coiled wires. Once you have your first layer of wires completed, wrap electrical tape around them to hold them in place. Cover all of the wires, but leave the last coil exposed so you can continue wrapping other layers.^{[7]
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- If you don’t have electrical tape, you can use clear tape or duct tape instead.
- Make sure there aren’t lumps in the tape or else it will be more difficult to coil the next layer.
4
Make 7-8 more layers of wires to make your coil gun stronger. Continue using the wire you used for your first layer and coil it back toward your starting point. Make sure the wire is still going in the same direction around the pen or else the gun won’t work. Wrap the wire back and forth, putting electrical tape between each layer, until you’ve completed 7 or 8 layers of wire.^{[8]
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- You can make more layers of wire if you want, but 7-8 should be enough to shoot a projectile.

Part 3

Part 3 of 4:

Wiring the Gun

1
Solder the wire wrapped on your coil gun to the negative terminal on the capacitor. Take the end of the wire from your coils and cut it so it’s 6 in (15 cm) long. Look for a white stripe or “-” on the capacitor to find the negative terminal. Use a soldering gun to attach the wire to the capacitor. Make sure there’s a solid connection by lightly tugging on the wire.^{[9]
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- You can buy a soldering gun and solder material from your local hardware store.
2
Attach a black insulated wire to the positive terminal of the capacitor. Strip ¹⁄₂ in (1.3 cm) of the insulation off the end of a black wire using wire cutters. Hold the end of the wire next to the positive terminal on your capacitor and use your soldering gun to attach it. Tug it gently once it’s dry to make sure the connection is solid.^{[10]
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Tip: Coil the end of the wire around the terminal before you solder if you want a more solid connection. Make sure to wear rubber gloves to prevent any accidental shocks.
3
Run the black wire to a switch. The switch acts as the trigger for your coil gun. Cut your wire so it extends 3–4 in (7.6–10.2 cm) from your capacitor and strip ¹⁄₂ in (1.3 cm) of the insulation from the end. Feed the exposed wire into one of the ports on the switch terminal and tighten it in place with a screwdriver.^{[11]
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- Buy a switch from your local hardware or electronics store.
4
Connect the switch to your coil gun with another black wire. Cut another black wire so it’s about 3–4 in (7.6–10.2 cm) long. Strip ¹⁄₂ inch (1.3 cm) of the insulation off both ends of the wire. Feed one end of the wire into the second port on your switch and tighten it in place with a screwdriver. Solder the other end of the wire onto the copper wires on your coil gun to complete the circuit.
- Make sure your switch is in the off position before soldering it to your coil gun.

Part 4

Part 4 of 4:

Shooting the Coil Gun

1
Load a metal BB or piece of wire hanger into the pen barrel. Cut a ¹⁄₂–1 in (1.3–2.5 cm) section from a wire hanger if you want a dart-like projectile. Otherwise, you can use a BB or ball bearing as your projectile. Feed the projectile into the barrel of your coil gun.^{[12]
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- You can use any projectile as long as it’s magnetic.
2
Put the battery back in the camera and charge the capacitor for 5 seconds. Place the battery back in its terminal so a current can run through your circuit. Locate the triangular metal piece on the back of the circuit and press down on it with an insulated screwdriver. Hold the screwdriver there for 5 seconds so the capacitor can fully charge.^{[13]
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- Don’t touch the capacitor after it’s charged or else you will get shocked.
3
Turn on the switch to shoot the coil gun. Once the capacitor has been charged, flip the switch into the on position to shoot your gun. Turning on the switch completes the circuit and charges the coils around the barrel, propelling the projectile forward. Once you shoot the gun, leave the switch on for 1 minute so any leftover voltage in the capacitor can discharge safely.^{[14]
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- Make sure your gun isn’t aimed at any living thing since it will shoot quickly.
Tip: Prop up the end of your coil gun’s barrel to shoot your projectile farther.

Community Q&A
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Question

Could I use a bigger capacitor for more power?

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This answer was written by one of our trained team of researchers who validated it for accuracy and comprehensiveness.

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Staff Answer

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You can wire multiple capacitors in the circuit if you want the gun to shoot faster and further.
Question

How far can the projectile go?

Community Answer

With that capacitor, not very. This isn't a weapon. It is more like a school project.
Question

Does the capacitor for this have to be from a disposable camera?

Community Answer

Any capacitor should work. Bear in mind that if you get a capacitor that has a higher charge content, it will be more powerful.

Warnings

Wear rubber insulated gloves throughout the build to protect yourself from getting shocked.

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Never aim your coil gun at a living target.

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