I started playing with this several months ago. I had seen the film canister cannon and wondered about the possibilities. Initially I saw this: Pirate Cubicle Cannon. I then saw several other implementations all using a sprayed fuel, typically Binaca.
I thought that "autoloading" would be better than having to spray fuel into the canister and attach it. I thought that the fuel-air ratio was probably too rich, not too light in the Pirate Cannon but I planned on making a small hole in the film canister to relieve the pressure and allow fuel to flow in if it were indeed too light.
I built a prototype using butane as the fuel, piped in. There was no problem, just a _very_ rewarding *loud* report + fireball followed by insane laughter. Finally I calmed down and began thinking (ir)rationally.
As I thought about making a hole, my thoughts morphed from a small one to a larger one to a barrel: a-la the "ultimate spit-wad shooter".
I tried it and the performance was beyond anything I expected. I used a Bic Round-stik pen as the intitial barrel...hunting for ammo... would you know that Tic-Tacs fit really well in a Bic pen? Yeah and when the tic tac hurtled across the room, bounced of an angled door, down the hallway and ricocheted arround in the bathroom for a while I knew I had something.
I scoured the web looking for anything similar, I found one thing at the BleachSoft website. At instructables, I filtered through all the KNEX guns, marshmallow guns, airsoft guns, etc and turned up nothing. I have however recently seen several similar projects appearing here on instructables:
Small Dart Gun
Axe Rocket Launcher/ Mini Spud Gun
Mini Spud Gun, Classroom Nemesis
Mini Spud Gun
Now that my fear of being the sole corruptor of the DIY builders of the world has abated, and I will not share sole responsibility for the fallout, I present my work so far.
Step 1: Parts Overview
This could be 3/4" stock, 1" stock, Exotic hardwoods...anything you want. For office
expediency a flat ruler could be employed or better, one of the square cross-section yard
sticks. I'm using 3/4" here. It would be great to combine this: Wooden Luger with the project...mayabe in the future.
2. Lighter to be used as trigger and fuel control
- I used the illustrated Ronson lighter. Almost any would work. Make sure it is refillable.
You will be refilling it. Trust me. Choose one and get several of the same type -- they all
have little differences. Once you've used one type it will be easier in future devices.
3. Film Canisters.
- These are easily available and will be used as the combustion chamber and for
changing barrels for firing a variety of ammunition. Agian, you may want several. I have
not tried the translucent Fuji variety or the oval advantix ones.
4. Fender washer.
- Dimentions are not critical. You could use any round rigid flat piece of material.
This will support the back of the lid as it attaches to the body of the device.
I've used plastic scrap before. You want a rigid plataform that adheres well to the lid
and the device body.
- shown are a standard Bic pen and a black tube - this is the spindle from a CD spindle
pack. Other options are chapstik tube, pen barrels of other dimentions; basically any
straight piece of tube of a diameter that matches the ammo you want.
6. Candle lighter.
- From the dollar store. Bascially we are harvesting the wire and the gas tube from this.
I also use the piezo striker as it has the wire already soldered neatly to one of the leads.
- Used to convey spark from piezo into chamber. Not needed if using wire from
1. Saw - cutting wood to proper angles / lengths
2. Dremel or other carving tool for channeling the wood to accept the lighter
3. Drill or method of making long thin holes for gastube and wires
4. Soldering iron - for attaching / tinning wires
5. Hot melt glue gun - could use another adhesive if desired
That's it. Move on for the good stuff.