Tactical Starch Delivery System
The Tactical Starch Delivery System, or TSDS, is sometimes referred to as a potato gun, spud cannon, spudzooka, or potato shooter. The particular one described here shoots potatoes, apples, or pears with incredible accuracy, velocity, and distance. In fact, in one test, a horse shot with this gun was killed on impact using a standard-issue Idaho potato.
To make the TSDS, the following is needed:
1) 5′ of 2″ PVC pipe
2) 8″ of 4″ PVC pipe
3) One 4″ to 2″ PVC adaptor bell
4) One 4″ Cleanout Plug Adaptor which fits over the end of the piece of 4″ PVC
5) One 4″ Cleanout Plug (this plug is the kind with the square lug for a wrench and threads around the outside of the plug–ask your local hardware store worker if you can’t identify it)
6) One Replacement Gas Grill Ignitor
7) One Large Paper Clip
8.) Needle-nose Pliers
9) PVC Cement (MUST be PVC-specific cement)
10) Roll of Electrical (black) tape
11) Roll of Duct (gray) tape
12) At least as many brain cells as a plastic cup
15) A broom handle to use as a ramrod to push the potato down into the barrel
16) One can of extra-hold aerosol hair spray OR one can of aerosol ether-based engine starting fluid (starting fluid is preferable)
17) An electric drill
Cement the bell adaptor to the piece of 2″ PVC, then to the piece of 4″ PVC. Next, cement the cleanout plug adaptor to the other end of the 4″ PVC.
Take the paper clip and attach it to the terminal on the side of the ignitor (not the end) and bend it so it’s about 1/2″ from the terminal on the end of the ignitor. Push the ignitor and you should get a spark that jumps between the two. If you get shocked (don’t worry, it doesn’t hurt) you’re touching one of the terminals. Move your finger and try again. If you don’t get shocked and you don’t see a spark, bend the paper clip closer to the terminal on the end and try again until you see a spark jump between the terminals every time. Now take some electrical tape and tape the paper clip to the side terminal so that it doesn’t move, but make sure you don’t cover the area that the spark jumps to.
There should be two ‘arms’, one on either side of the ignitor. Cut these off with the knife so that there’s no pieces sticking out. Now drill a hole in the middle of the piece of 4″ PVC that the ignitor will fit into completely, but snugly. If the hole’s too big, you need to wrap electrical tape around the uppermost part of the ignitor below the plunger collar(the terminal on the end is the bottom, wrap tape around the other end below the collar so that it makes it fit more snugly into the hole) so that there’s a fair seal. It doesn’t have to be air-tight, but if it releases too much gas you could experience a loss in power, the ignitor could be thrown from the gun, or hot gases may shoot out of the hole where the ignitor is or was. Again, check that the spark is arcing inside the piece of 4″ PVC.
Finally, take sand paper and sharpen the muzzle end of the 2″ PVC, which is to be your barrel. It doesn’t have to be razor sharp, but the sharper it is, the easier it will be to push the potato down and have the parts that don’t fit cut off to ensure a perfect seal. Sand from the inside of the pipe so that it cuts a piece a tiny bit bigger than the inside diameter so the seal is better between the potato and the barrel.
To fire, perform the following steps:
1) Get a potato that is bigger than the barrel and push it down onto the end of the barrel so that it cuts the excess away (you sharpened it, remember?).
2) Making sure that the end cap is off, use the ramrod to push the potato all the way down to the end of the barrel, but not down into the combustion chamber (the 4″ PVC section).
3) Spray some propellant into the combustion chamber and put the cap on. If you’re using extra-hold hair spray, give it a generous, 3-second squirt. If you’re using ether, a 1/4 second squirt is enough. If you put more, the mixture is too rich, and there’s not enough oxygen to ignite the ether, so nothing happens. Ether is definitely harder to get the right amount of, but if you can find the right amount it’s much better because it burns very clean and doesn’t fowl up the inside of the combustion chamber. The hair spray leaves a black, sticky coating on the inside of the chamber, which really sucks, but it’s much easier to get the right amount in there, because there’s much more tolerance in the range of the amount of hair spray that will ignite. Ether needs a specific amount, no more, no less, but hairspray can have as little as 2 seconds or as much as 5 and still work reasonably well.
4) Once you’ve sprayed in the propellant, quickly put on the cap to prevent the propellant from escaping from the combustion chamber. It doesn’t have to be tight, just give it a spin and it’s probably tight enough. If it doesn’t fall off, it’s plenty tight.
5) Hit the plunger on the ignitor to fire the cannon.
Remember, this will break 1/2″ ply wood at 15′ in the right combination of propellant and air. It will also kill a horse. Needless to say, it will leave a nasty dent in a car, probably crack the window (especially with apples), and would kill a person within 50′ if hit in the neck or upper torso. BE CAREFUL with this thing. Don’t put your hand in front of the muzzle; I’ve known people who’ve lost fingers and/or hands doing that. Don’t look down the barrel when you’re pushing the plunger unless it’s sat open with no propellant sprayed in for at least 5 minutes. I learned this the hard way, as I lost a small bit of hair and most of one eyebrow the first time I made one of these; I looked in the combustion chamber with ether in there and hit the ignitor. FOOM! and little pieces of hair floated this way and that… kinda annoying.
Neither I nor Psychotic are responsible if you fuck up, kill someone, break a window, damage a car, or hurt yourself. Whatever you do from here on in is your own business. We assume no liability whatsoever for the use of this information.
Many people have asked me “Is it legal to make a potato gun?” The answer: YES! It is not considered to be a firearm as long as you’re just shooting potatoes, apples, or pears with it. However, if you make one that shoots marbles, golf balls, or baseballs I’m not sure whether it’s legal or not. A tennis ball one probably wouldn’t be a good idea either. Of course, combine the tennis shooter with an exploding tennis ball bomb (see the Anarchist’s Cookbook for how to make these simple and fun bombs) and you’ve got a mobile mortar… definitely NOT legal.