Potato Guns Spud Gun Types
SPUD GUN FAQ
Many of you have been asking if I still use my spud guns. Hell Yes, every chance I
get, but finding an adequate and safe launching place isn't easy. The following is a list of
frequently asked questions regarding potato guns and
What is a potato cannon or spud guns?
What are spud guns made of?
Are spud guns dangerous?
What are the legal implications?
How easy is it to build a spud gun?
What does it cost to build a spud gun?
What is a combustion spud gun?
What is a pneumatic spud gun?
What are the advantages to each?
Can I use DWV pipe or cellulose, even though it says not for pressure?
What does PVC stand for?
How does PVC differ from ABS? Which is better?
SPUD GUN HISTORY
No one knows who started them. Legend states they originated from tennis ball cannons made from pop
cans and lighter fluid, back in the 50's. They come by many names, spudzookas, PVC mortars,
potato guns, spudguns, potato cannons. But they are all the same thing: an array of plastic
pipe which propels a projectile, usually a potato, at incredible speeds, by means of combusted
gas or compressed air. They can also be used for more practical purposes, i.e. line
Most spud guns are made out of Schedule 40 PVC pipe, the plumbers standard. They are
NEVER CONSTRUCTED from DWV (drain, waste, vent) pipe as it is not meant for pressure and the
resulting effects if pressurized could be deadly. It is thick and durable and has a great pressure
rating to around 300 psi, so it is safe for minor 100 psi launches. Another method of construction
is using ABS pipe, another durable type. I do all my shopping at the Home Depot. They have an
excellent selection of every kind of pipe and connector, and their prices are very inexpensive.
Radio Shack supplies all the electronics. Valves and hose clamps (for support) can be found at auto
Like anything device created to launch something, spud guns are dangerous. They propel projectiles at high velocity, and
thus you don't want to get hit by one or point them at windows or other important things such as
cats. And when you shoot things like ice or wood as opposed to potatoes, they have much more mass
and become even more dangerous, considering they do not vaporize on contact.
Combustion cannons use a flammable propellant and thus have a danger of exploding or fire, however
this is rare if proper methods are used. Compressed
air cannons can be regulated to within the limits of the PVC pressure rating but still
risk rupture or blown valves, however the usual pressure of 100 psi is well within the limits of
the pipe. Combustion cannons can send the endcap of the pipe shooting off, and they can shoot large
flames from the barrel. But they are generally safe when used with precaution and common sense.
Legality is a sketchy issue. All seem to agree they are novelty devices, for
amusement only. For all intents and purposes, they are a recreational device which shoots small
projectiles at stationary targets. Obviously, you don't want to go shooting small rodents out, or
billiard balls at billboards, but for the most part there shouldn't be a problem. Combustion
cannons may cause a noise problem however. I advise you check with your state and local law
enforcement agency for further information. The following is a letter that finds its way onto most
potato gun sites about legality. I cannot vouch for its validity, however.
Building these can be fun, but the skill needed is advanced. You need a working
knowledge of mechanics, hardware, construction and physics to know what you are doing, and it is
good to know simple electronics for the triggers to some guns. Many young (16 or younger) people
ask me about these, often for science projects, and I always advise them to consult an adult first.
It's also a great bonding experience (hint hint you dads out there...)
Simple tools are all that is necessary. For more advanced spud guns, dremels or hacksaws may be
necessary. Make sure to use proper ventilation when gluing and priming. Soldering electric
components also takes some skill. Other launchers exist which are vastly more complicated,
requiring more skill.
Building a spud gun is a relatively inexpensive hobby. Most PVC pipe
ranges from $2 to $6 for 10 foot sections. Joints and connectors are around $0.39 to $4 for large
pieces. Glue and primer are about $3 each. Valves run from around $8 for good ball joints to $12
for electronic sprinkler valves and larger brass ball valves. Electronics run around $12 for all
the necessary switches and components. All in all, expect to spend around $30 to $40 to make a good
gun. Prices go higher as the diameter and size of the gun increases.
Combustion cannons have a large chamber which reduces to a smaller diameter pipe,
from which the potato is launched. Combustion is achieved by spraying in a propellant, usually
hairspray. A flint or electric lantern igniter is used to generate a spark, which ignites the
gases, propelling the potato, which can exit the barrel baked.
PNEUMATIC SPUD CANNONS
Pneumatic cannons are completely different, and thought of as much safer and more
powerful. These cannons have two chambers, one in which air is compressed, and another in which the
projectile is shot. Between these two chambers is a diaphragm, or a valve of some sort. When the
valve is opened or the diaphragm flexed, massive amounts of high pressure air force the potato
What are the advantages to each cannon?
Pneumatic Spud Guns:
Pros: More power; regulated pressure, won't accidentally explode
or misfire. Always fires. Can shoot water, ice, paper, snow, and other objects; quiet.
Cons: Expensive to build, complicated parts; long reload time, quiet. Valves need
maintenance and cleaning, some require batteries.
Combustion Spud Guns:
Pros: Ease of use, simple design, low cost; fast reload time. Can make some cool
fiery projectiles, loud.
Cons: Dangerous, can burn things or people, misfires or doesn't fire occasionally,
size can be a hindrance, loud.
PVC stands for Polyvinyl Chloride. Here is a link to PVC pipe statistcs and its
applications: PVC FAQ.
ABS VS. PVC
The debate continues as to which pipe is better. I personally use PVC; this is only because I have
not tried ABS yet. I am told ABS is stronger and cheaper, but I suggest you do your own