Part two of the epic adventure that is… Building The Coil Gun!
The Build
Now that we have all the parts we need we need to build the Coil Gun.
The enclosure is necessary to protect the components from the outside world as well as to protect the outside world from the components (aka fingers getting blown off). I used an enclosure from a local electronics store. It cost me around $8 and has plenty of room for all the hardware.
Ok so now you have to build the capacitor bank. The capacitors must be wired in parallel (+ to + and - to -). I used a stiff, heavy gauge wire that I bent into shape using needle nosed pliers. This allows the capacitor bank to keep its shape and it is a lot easier to solder together than with individual wires.
Once you have constructed the capacitor bank you have to connect it to the capacitor connector on the charging circuit. Personally I used some medium gauge wire that I had lying around, but you can use anything really (as long as it can handle the current). You also have to make sure that the capacitor bank is connected with the right polarity. (+ to+ and- to -). Then you have to wire up the charging switch. You can use any type of wire for this as the switch is super low current, but I chose to use some scrap magnet wire because it was thin enough to solder to the switch pads. The other end of this wire is connected to the switch on the enclosure and is used to start or stop the charging cycle.
The charging and firing switches, capable of withstanding up to 10 Amps. (Smaller switches become welded shut when the coil gun is fired)
My power supply of choice is a D cell battery. The D size will give many more shots than a AA before having to be replaced. Also, using a battery will also allow the coil gun to be portable. To wire the battery all you have to do is solder the + and - from the holder to the + and - on the charging circuit.
Now the only part left to wire is the actual coil. In my coil gun I wired a switch in series with the capacitor bank and the coil. When the switch is turned on the capacitors are directly discharged into the coil.
The “gun” part of the coil gun was made using a BIC pen. The pen was disassembled and everything but the tube was thrown out. The pen tube will act as the barrel of the gun.
I drilled a small hole at the end of the pen tube to help reduce the suction effect that is produced when the projectile is leaving the barrel.
To build the actual coil I used magnet wire and wrapped it around the bottom of the tube about 1.5 cm from the end. The coil was about 3 cm wide and after every layer I “laminated” it with scotch tape. This helps the coil keep its shape as well as preventing shorts. When you make your coil you always have to remember to wrap the wire the same direction in every layer. (clockwise or counter clockwise) Also you should make sure that the turns are tight and close together but not crossing each other. If you follow these rules you will end up with a very powerful coil. My coil had 8 layers.
At the last minute I decided to add a diode across the firing switch. The diode protects the capacitors from feedback created in the coil after firing.
Once everything was wired up and taped in the enclosure I covered most exposed parts with electrical tape to reduce the chances of a short. (Or the dreadful blown off finger)
The projectile. (A machine screw cut with a hacksaw)
The finished coil gun. w00t!
Now I just have to test it and tweak it 
Comments
Nice work! im starting with my tomorrow! 
i just got 20 cameras from my cameradealer for free.
Wow, this is a great tutorial, I have visited many coilgun tutorials but most of them had bad explanations, blurry pictures, etc.
Keep up the good work
P.S. I’m an electronics noob and this was the only tutorial of the sort that made sense to me
Thanks for the comments Rob and Dezmond!
Hey i was wondering if you could post a picture of the electronics schematics, or a better picture of the whole electronic setup. This is a really good tutorial especially with the coil gun v. 1 with the whole explanation of how a coil gun works.
Do you have any tips for winding a coil? I have made and fired my coilgun with two capacitors (10,000uF at 100V each) yet i can only shoot a small nail about 40cm. I have a very strong suspicion that my coil is not wound properly and is loosing energy. Is thickness of the coil better than length?
Lol i found out my problems with my gun, been using 24V to charge up rather than 100V and my coil wire is way too thick 8mm diametre including insulation. Ill post videos when i get it working properly
so hey matt i did this for school a while back and i only got a “C” for it ( i hate my teacher) it really outdid every-one elses stuff i mean a paper sword was the best they did and i did a coil gun, you know teach gime some cred not a “c” lol
i just wanted to share with you guys this trick i found…
go to a local walgreens and ask if they have anyused/developed disposable camera’s i got about 100 camera’s and allot of them had fully charged AA’s in them, this can also be help full in a couple ways. 1. allot of AA’s 2. allot of capacitors (choose quality stuff outa selection) 3. can choose best circuit board to use (easier soldering,led light, etc. etc.)
(also dont use metal inclosures)
(dont bring to school)
(and remember to discharge capacitors (just touch both contacts using a screwdriver with rubber handle)on used disposable camera’s people usually think their is one more pic so they charge it up but then they find out its outa film)
hey great tutorial! using it for my physics coursework! what voltages do you think an average disposable cameras flash PCB can handle? anything beyond 24v? or not even that much also do you think un-insulated copper wire would do the jobe magnetic wire is especialy hard to get where i live and im just going to buy a load of capacitors how many micro farads were the ones you used in your rig? cheers and regards
I have a “bank” of supercapacitors with a storage ability of 5 Farads at 12V, with access to free “custom-made” coils what size of wire would need to be used to withstand muliple “shots”???
Great tutorial. The only one with decent sized pictures and explanations. I was wondering, though, how do you solder those capacitors onto the wire for the capacitor bank? I’ve been trying to get one on a copper wire forever but it wont stick…
Hey thanks moshee! Try cleaning the copper with some alcohol before you solder maybe, or use some flux
This is really cool.I would suggest that instead of buying the cameras go to any place that develops film and say to the person at the counter “may I please have some used disposable cameras” and they will give you some cameras for free.
hey, i have 7 capacitors from cameras and 2 larger ones (must be at least twice the size of the camera flash capacitors) but the nails that my coil gun fired hardly even dent a piece of paper, i think i have a weak coil but i dont know 
what is the best way to make a coil?
thanks
hey guys, I live in Romania so i don’t realy have where to get all of this things. I managed to get everything except the Diode, switches and the box
some help please?
please reply. Where to wire the firing switch and the coil gun it’s self???
Hey Jack, to make a good coil make sure that all your layers are wrapped in the same direction. Aka, all clockwise, or all counterclockwise. You probably need at least 5 layers too. The more the better :). Also the position of the coil is key. If the coil is to far forward it wont have as much pulling force. If it is too far back it wont deactivate in time and stop the projectile from coming out from the barrel. Try sliding the coil up and down the barrel until you find the optimal point.
Alincrys, the coil is wired directly to the capacitor bank with the firing switch in between. Aka, when the gun is fired the capacitor bank is completely shorted over the coil. Thx for leaving a comment!!
Great explanation im doin one for 7th grade any comments on how to make a 3 stage one? (link website if theres a “better guide”)
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