How to Make a Mini Dart Gun w/Multiple Fire Modes

I've been playing with the idea of what cool things I might be able to do with soda bottle preforms for a little while now and this is what I've come up with. The dart gun in this video uses two different firing methods that are commonly used in larger potato cannons, a pneumatic firing option, as well as a simple combustion option. A coaxial piston valve is my personal favorite mechanism for these sort of projects, and this video shows how it works quite well through the clear chamber. For the combustion design the fuel of choice is isopropyl alcohol, preferably 70% or greater.

How I made the darts in this video: http://youtu.be/BRUYdmOKLyM

How to make a mini cannon from a lighter (another mini airsoft cannon): http://youtu.be/QGj8xMDRSQ0

How to make water bottle rockets: http://youtu.be/YRtFY_O0HcU

<p>how many lighters do you go through in a week? because you use a lot of peso electric igniters.</p>
Is there a way to fire 3 or 4 airsoft bbs at one time
Yeah, load three or four of them in the barrel.
<p>I made two versions of this project (awesome, btw):</p><p>1. With a 10 oz water bottle. works great</p><p>2. With a 2 L pop bottle. Held more air, so it shot farther.</p><p>Thanks for another cool project!</p>
Would alcohol out of the bottle work like vodka for example work as fuel for a spud gun project
I like all of your projects
<p>what if you were to use the hydrogen gas you explained how to make in a previous video as a fuel source? I've always had that thought and have made a few alcohol fueled mini dart guns but have yet to try hydrogen gas so what do you think nighthawk would it work? Future video? It would be pretty fun to try</p>
well I shaved it down with a file and it's still a really tight fit
how do you make the piston I am trying to make a coaxial gun with a marker and a airsoft barrel but the piston I made is too tight of a fit in the marker and it won't move should I be concerned
Just sand it down slightly and it will move better.
Great idea by the way
Can you link a website for the performs
<p>Very interesting Night Hawk, Definatly another quality project :)</p>
Would deodorant work as a propellant as well or any other flammable liquid
<p>Alcohol is really the best fuel. Nothing else will work nearly as well.</p>
Ingenious project! I like how you used the soda cap as the release for the coaxial piston gun version... I'll have to make one sometime:D How much pressure was it at when you fired it?<br>Thanks,<br>Kyle
<p>About 60-80psi. The preforms can stand many hundreds of psi before rupturing but the soda bottle caps are the weak spot and can only stand about 100 after they've had a hole drilled through for the valve.</p>
Cool !