A spud gun/potato gun/organics accelorator is a simple tool used to
accelorate a spud, apple, corn cob or any other semi-soft friut or vege
to high speeds-sorta like a bio-degradeable projectile. Yes it is a
type of fire arm and, according to Wikipedia it is banned in Germany, parts of the US, parts of the UK, Western Aussie among other place in the world. I take no responcibility for anything you do with anything thats on this site. There are three different types of spud guns. Combustion, Pneumatic
and a hybrid of the two. Pneumatic is a bit more pricey to build than
the combustion but it is the safest. It uses compressed gas to launch
the spud. Because I am cheap, and I live in a country with free quality
medical care (ACC), I built the combustion type. Very easy to assemble
and the parts are affordable and accessable.
List of things you need
- PVC pipe 83 cm in length, 5.5 cm wide. This wil be the barrel.
- PVC pipe reducer, reduce from roughly 11.5 cm to 5.5cm
- PVC pipe 57cm long 11 cm wide. This is the combustion chamber.
- PVC threaded screw lid to fit on one end of the chamber.
- Two screws to act as a spark plug
- Either a BBQ lighter (bit expensive to get a quality one) or a stun gun (very pricey and illegal in alot of places) or use a transformer like I did.
- Some insulatored copper wire and a few batteries
- A thin pole or strong stick bit longer than the barrel (to push the spud down)
- PVC glue/cement
- Deodorant (fuel)
thing is either cheap or can be found in the home. The measurements
arn't very correct so make sure you understand the concept and how it
all works before you go out and buy the stuff. Also, alot of shops are
weary of sell these parts to youngish people because they know what you
are going to do with it and the police don't like like it. I sure you
can find a way round it.
Now for the putting together of the whole thing.
1. Get your barrel. Make sure it fits tightly into the reducer. If it dosen't you have got the wrong pipe. If it fits just right, hard to put in and hard to pull out, you got the right idea. Clean the part of the pipe that will be in contact with the reducer with a slightly damp cloth. Do the same for the reducer.
2. Make sure that each part is clean and is now dry. Put the PVC cement in the reducer where the two peices come in contact. Be liberal with the cement. Spread it around to make a nice even film with your finger (not recomended) or a knife.
3. Quickly but carefully get the barrel and twist it into the reducer until it won't go any further. Make sure that the barrel is reasonable straight.
4. Do the same for the combustion chamber: Clean both pieces, glue and twist in.
5. Now to glue the threaded screw top. Remove the cap so you have just got the ring bit. Clean, glue and twist. Make sure the cap can screw on and off with ease.
6. Leave the whole project to dry for about 24 hours just to be safe.
7. Now to make the ignition system. If you are going to be lazy and buy a BBQ lighter, installation is easy. Drill a fat whole big enough for the plug to fit in and glue it there. I suggest you buy the more expensive type as it will surely last longer. If you are going to do it my way you will need a transformer (see image). They are the things inside cell phone chargers, laptop chargers etc. Very common but make sure you use an old one because you can't use it again for your charger again.
8. Make sure you get a good step up/step down transformer. A good one is 230-240v:5v. Position the high voltage wires about 1mm apart. Connect a standard 9v battery to the low voltage side. Becarful: BIG SHOCK if you touch other wires. You should see a spark when you first connect the battery. if you don't use the set of wires on the other side. If you put the battery on/off on/off on/off fast and lot you will see many sparks. Use masking tape to mark which set of wires is which.
9. When drying is finished, drill two holes into the combustion chamber just far apart that when you put the screws in the just don't by 1mm or less. You can adjust the space between the screws by unscrewing one screw slightly. Connect the higher voltage wires to the screws and test if it sparks.
10. Solder the wires together and if you want buy a switch for your gun. Attach everything to the gun. I used zip ties because they are strong and I got a 1000 of them. Test the ignition again with everything on. If you are happy, its time to get to work!
Hopefully your gun is in working order. But before luanch I must, once again, give a warning. Here goes: WARNING: Alot of people don't like the idea of a potato flying into their heads, through their windows, hitting their precious cat, dog or cow or a spud knocking over their TV antennea on their roof. Also: old people phone the police to report anything slightly out of the norm, eg: someone broke into their car because it won't start, the neigbours lawmower is too loud or a shadey looking man is sweeping the street. So old people are bound to call the cops when they hear a gun shot (ie: sound of your potato cannon). And thats why the coppers don't like the guns. So make sure you are far away from anyone and shooting far away from anything. Shooting at your wall is ok if you have a good relationship with your neighbours.
Steps to sending spuds super-sonically into space (sort of):
1. Get a potato that is bigger than your barrel. Now make it fit. There must be no gaps between the spud and the wall of your barrel or else the gas will leak or the fireball will exit too quickly.
2. Get the pole. Shove that spud down the barrel so it sits just infront of the reducer.
3. Retest the spark. If its ok you are ready to add the fuel. The fuel can be gas from a flamable aerosol can. For first shooting I recomend a deodorant like LYNX because its has alchol, butane and Propane aswel as t-butly alchol (which sounds like a hybid of alchol and butane but I have no idea what it is). Don't use hair spay. Alot of sites recomend it but it leaves a gunky mess afterwards. Generally you can judge how flammable a substance is. 1 warning symbols=good, 2 warning symbol= pretty flippin good, 3 warning symbols=top quality.
4. Get a mate to help you. Get the gun horizonal and get him to hold the screw cap just next to the hole. You spay about 2-5 seconds worth of fuel itto the combustion chamber. When you are done immediatly screw the cap on tightly.
5. When you connect the battery the spud should start to move. It will move at about 150km/h so be careful. Makes a big bang.
6. After many launches you can try different fuels. I got my hands on a cannister of nail gun gas. 3 symbols which is always good.