What Is A Spudgun? What exactly is a spudgun...

[baseballkid781 0]

Spudguns, what are they? People think they only use potatos, and they find that stupid. Others think that they are only air powered or only combustion. And many don't even know what a spudgun is! A spudgun is a recreational launcher made to shoot a "spud" (or other ammunition) over far distances. This is accomplished by one of three ways. The first is by air pressure (usually the strongest), called pneumatic. The second is combustion, igniting a fuel to build pressure and launch the projectile. The last is a hybrid launcher, a mix of combustion and pneumatic spudguns.

 

Combustion: Usually very simple in design, just a chamber and a barrel. Of course, they get more complicated in design as they get more advanced. There is also a need of ignition, usually a barbecue lighter or a spark. The main fuels are: hairspray, propane, WD40, and other liquids/gases that ignite. Believe it or not, these are weaker than pneumatics.

 

Pneumatic: Sort of complicated but usually cost more than combustions, due to having to use valves and such. These use airpressure, either a handpump (which is sort of dangerous, because you don't know how much pressure you have) or a compressor (which is easier and safer). These can launch potatos at recorded records of 750 yards!

 

Hybrids: These are very rarely made, as they are the king of complications. So much can go wrong with these. These are recommended to use sch80 pipes since the pipe has to handle lots and LOTS of pressure.

 

These are spudguns. Look them up on google and you'll find more targeted and detailed information and certain spudguns.

198973[/snapback]

Spud guns, potato cannons, or produce accelerators are all recreational launching devices usually made of polyvinyl chloride (PVC) water pipe. There are two common means to launch projectiles from a spudgun. The first uses the energy stored in a compressed gas and the second, more popular method, uses the energy stored in combustible fuel vapors to heat the air and cause it to expand. There is a quite rare mix of the two, a "hybrid", that combusts a pressurized fuel-air mixture. The object of these varieties is to propel "non-destructive" projectiles in the direction of a designated (safe) target for fun. Common projectiles include: mandarins, potatoes, tennis balls, and golf balls. They are a particularly popular home-made class of projectile launchers because of their low cost to build: a simple hairspray powered gun costs no more than $20 in PVC and glue, less if parts can be scrounged.

 

Combustion launchers-

Combustion powered spudguns have four basic elements:

Fuel system

Combustion chamber

Ignition source

Barrel

In order to fire, the operator loads a projectile (usually a potato) into the barrel, adds fuel to the combustion chamber (for example aerosols or propane), and triggers the ignition source (e.g. a piezoelectric BBQ ignitor). The fuel should then ignite, create hot expanding gases, and force the projectile out of the barrel. Distances vary greatly depending on the type of fuel used, the size of the launcher, and the "idealness" of the fuel/air ratio; 100 metres is a common distance.

High tech combustion launchers may now include metered propane injection, chamber fans, multiple spark gaps (spark strips), and high voltage ignition sources (flyback circuits, stun guns, camera flashes, etc). Combustion launchers are mechanically simple, but are weaker in typical situations compared to a pneumatic launcher of the same size. Potato guns are often painted to increase their aesthetic value and to cover unsightly primer stains. Krylon Fusion, a type of paint specifically made for plastics, is the most common type of spray paint used on potato cannons.

For instructions on how to build a combustion launcher click

here.

 

Pneumatic launchers-

Pneumatic launchers consist of five basic elements:

Compressed gas storage reservoir (chamber for short)

Filling valve (bicycle Schrader valves, quick-disconnects, etc.)

Main valve (ball valves, sprinkler valves, piston valves, quick-exhaust valves, and burst disks are the most common)

Barrel

Pressure gauge (for safety & repeatable launches)

In order to fire, the operator loads a projectile into the barrel, fills the chamber with a compressed gas (air compressors, hand pumps, and regulated bottled gas are common filling methods), and activates the main valve thus dumping the air in the chamber to the barrel.

The expansion of the compressed gas propels the projectile down the barrel. The barrel length determines the amount of energy transferred to the projectile and ultimately the velocity of the projectile.

High performance launchers use techniques such as modifying valves for faster opening times, using homemade valves, and maximizing the amount of airflow through the valve.

 

Hybrid launchers-

A hybrid launcher consists of seven basic elements

High pressure combustion chamber

Pressure-triggered main valve (usually a burst disk)

Barrel

Fuel system (usually metered propane)

Air filling valve

Ingition source

One or more pressure gauges

A hybrid is a type of spudgun that combines principles of the combustion and pneumatic spudgun. It uses a pressurized mixture of fuel and air to get more power out of a given chamber volume. In order to fire, the operator first inserts a burst disk, usually consisting of aluminium foil or plastic, between the chamber and barrel. A cam coupling or union is used to hold the burst disk in place. The . when the ignition source is triggered, the pressure from the combustion ruptures the burst disk and propels the projectile out of the barrel. The hybrid is capable of higher velocities than a combustion or pneumatic spudgun, projectiles fired by a hybrid have broken the sound barrier (Source). A hybrid using twice as much fuel and air as a comparable combustion gun is said to be using a 2X mix, higher mixtures can be used and will produce even higher pressures. The fuel and air needs to be measured and matched carefully to ensure reliable operation, pressure gauges and fuel meters are used for this. A pressure gauge with a check valve can also be added to record the peak chamber pressure of the gun.

 

SAFETY: A hybrid is the most dangerous launcher that can be built. It is advised to build with pipe that can handle the high pressure environment (200+ PSI) such as Sch. 80 PVC or metal. Remote ignition is a must, and the limit of a 4x propane/ 4 atmosphere mix should never be breached. If a higher mix is attempted, DDT (deflagration to detonation transition) can occur, causing an extreme pressure spike. Most pipe cannot handle the spike, and will shatter, launching plastic shards everywhere. Therefore utmost care must be taken with these launchers.

 

Performance issues-

Some tricks to improve the performance of a pneumatic launcher include:

 

Using a tight fitting wadding will. This considerably improves the energy efficency of what you are shooting because it provides a tight seal around your projectile. This also allows you to shoot smaller objects.

 

Oiling the barrel (the less friction and resistance, the faster the potato will shoot)

 

Lubricating the main valve (if it's a ball valve) with dish soap. It is bad to use oil, as it will cause deterioration of the ball seal. Lubricating the valve makes it easier, and therefore faster, to open the valve.

 

Obtaining higher pressure piping and a higher pressure pump. However no PVC based chamber should be charged to more than 1250psi. The the pipe may say it can take more pressure; that is for water, not air.

 

Be sure to file down the end of the barrel to a sharp edge so that when you load a potato it is trimmed by the sharpened edges to the correct size. This kind of modification is called a Muzzle Knife.

 

To improve the performance of a combustion launcher try:

 

Patching the potato with polyethylene plastic - often you can cut patches from the same bag the potatoes came in - will improve both accuracy and range. To use a patch, place the patch (about twice the barrel diameter) over the muzzle then load the pre-sized projectile. Be careful about chamber pressure - patching can raise pressures considerably.

 

Blowing out the barrel and combustion chamber after each shot to remove the burnt gasses will promote more even and predictable combustion.

 

Use less fuel than you expect - a little goes a long way and you will not get ignition with an over-rich mixture.

 

Safety issues-

Improperly designed or assembled spud guns can be unsafe. Using proper assembly techniques and correct materials (pressure rated pipe and fittings) is essential. This is especially important in pneumatic guns, and even more so in a hybrid. It should be noted that PVC becomes brittle in low temperatures, and can be unsafe (especially for pneumatic use) when it's below freezing. The use of a spud gun which has developed visible structural defects (ie. cracks) or has not been constructed properly is dangerous and can result in serious injury. Safety is paramount while operating a spudgun; treat them with the same respect you would a real gun. Some spud guns are loud enough to require hearing protection.

 

Legal issues-

The United States Bureau of Alcohol, Tobacco, and Firearms does not classify spud guns as firearms. However, certain states and most cities have outlawed them. Check with your local law agency before shooting a spudgun to determine their legality. Never fire a spudgun within city limits, there are too many dangers involved by doing so. If authorities tell you not to use a spudgun in a certain area, it is in your best interest to follow their directions.

Vandalism that involves the use of spudguns contributes to the illegality of the hobby, so if you know someone who intends to use a spudgun for such purposes, alert authorities immediately. The use of dangerous, explosive and/or flammable projectiles is illegal and not condoned by the spud gunning community.

All spud guns have been classified as illegal in Western Australia.

All combustion spud guns are considered firearms in Germany.

Pneumatic spud guns are illegal to possess if you are under 16 in New York.

In the UK, pneumatic spud guns with projectile energy greater than 4 joules (3 ftˇlbf) are classified as section 1 firearms and require a license. In recent years, with the rise of spud gun use, there has often been much debate as to whether or not spud guns should actually be classed as Light Air Weapons. If spud guns were to be reclassified, then their maximum lawful projectile energy would be 12 ft/lbf, not 3. However, as the current law should be adhered to until spud guns are officially reclassified (if they ever are), they should not be more poweful than 3 ft/lbf.

In Walnut Creek, California, potato cannons are considered legal.

In Glendale, Arizona and Phoenix, Arizona combustion spudguns are considered firearms.

[Cool_Freaker 0]

There was an article on "Howstuffworks" that explained it .. hahah HMMM

[tdktank59 0]

A kid across the street had one we would shoot it out of his back yard at the hill and stuff it was fun!!!but he moved away to go to the coast guard meh w.ei want to make my own lolanywyas yeah!!!potateos are good eating btw...

[posterboy 0]

I love spud guns, if they were the only guns the world be a different place.

Its great to see someone has developed the art of spudgunning to such a refined level, nice site too!

 

Spudguns, what are they? People think they only use potatos, and they find that stupid. Others think that they are only air powered or only combustion. And many don't even know what a spudgun is! A spudgun is a recreational launcher made to shoot a "spud" (or other ammunition) over far distances. This is accomplished by one of three ways. The first is by air pressure (usually the strongest), called pneumatic. The second is combustion, igniting a fuel to build pressure and launch the projectile. The last is a hybrid launcher, a mix of combustion and pneumatic spudguns.

 

Combustion: Usually very simple in design, just a chamber and a barrel. Of course, they get more complicated in design as they get more advanced. There is also a need of ignition, usually a barbecue lighter or a spark. The main fuels are: hairspray, propane, WD40, and other liquids/gases that ignite. Believe it or not, these are weaker than pneumatics.

 

Pneumatic: Sort of complicated but usually cost more than combustions, due to having to use valves and such. These use airpressure, either a handpump (which is sort of dangerous, because you don't know how much pressure you have) or a compressor (which is easier and safer). These can launch potatos at recorded records of 750 yards!

 

Hybrids: These are very rarely made, as they are the king of complications. So much can go wrong with these. These are recommended to use sch80 pipes since the pipe has to handle lots and LOTS of pressure.

 

These are spudguns. Look them up on google and you'll find more targeted and detailed information and certain spudguns.

198973[/snapback]

[Disco 0]

My brother used to make these when he was younger, he and his friend would have contests to see who's could shoot farthest. All they used was a section of pvc pipe, with a T-bend thing attatched at one end, and the back of the T-section capped off and glued. They'd unscrew the other part of the T and fill it with fuel, (usually Arid XX spray deodorant) and use a grill lighter to ignite it. Unfortunately, our parents pulled the plug on our experiments when we started testing them without potatoes... A spud gun full of propellant with no projectile makes a reeeally nice flare. 15-foot fireballs shooting into the air over our back yard didn't float too well with my dad though.Anyway, that's a nice site you've made there, and I'd encourage anyone who's interested to try making a spud gun. Just make sure you're careful and don't blame me if something goes wrong. You ARE dealing with combustible gases, and if you construct one of these the wrong way, you could end up with something close to a pipe bomb. So uh... yeah. Be careful.

[Zorkaplex 0]

LOL this topic reminds me of the time a friend of mine and i launched twinkies out of his spud gun to observe twinkie arrow dynamics. It did not turn out too well and we used hairspray and it caught the twinkie on fire!Good stuff spud guns.