SpudFiles Wiki - User contributions [en]

Combustion cannon

2005-11-18T00:37:40Z

1984: Reverted changes made by user promoting own site

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 [[aerosol]]s 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 and the [[stoichiometry]] of the fuel/air mixture, the size and [[chamber to barrel ratio]] (C:B ratio) of the launcher; 100 metres is a common distance.

Improvements on the basic combustion launcher include optimized C:B ratios, [[fuel meter|metered propane]] injection, [[chamber fan]]s, multiple [[spark gap]]s ([[spark strip]]s), and high voltage ignition sources ([[flyback circuit]]s, [[stun gun]]s, [[camera flash]]es, etc). Combustion launchers are mechanically simple, but are less powerful 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.

<nowiki>*) </nowiki>the mass of the projectile is high enough that the faster cannon is not "solely" decided by the speed sound in the gas and the flow of the valve, and low enough that these things still matter. This will include almost any projectile you'll ever shoot.

Main Page

2005-11-17T22:19:09Z

1984: Reverting changes

[[What is a spudgun?]]

[[Combustion cannon]]s

[[Pneumatic cannon]]s

[[Hybrid cannon]]s

[[BB machine gun]]s

[[Cannon construction]]

[[Launcher configuration]]

[[Safety]]

[[Legal issues]]

[[History]]

This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. All of this is totally free so be happy and get on to registering and posting!

-PCGUY, maker of SpudFiles

==External links==

*[http://www.utopia.bcpneumatics.com Utopia, video tutorials (in part by PCGUY)]
*[http://www.bavetta.com/aircannon.html Air Cannon Barrel Length Numerical Analysis]
*[http://www1.iwvisp.com/thehalls/ggdt Gas Gun Design Tool, simulation program for pneumatic guns]
*[http://www.spudfiles.com/Other/are_they_legal.php ATF Correspondence concerning spud guns]
*[http://www.spudfiles.com Spud Files (aka The Spud Cannon Database)]
*[http://www.spudtech.com Great source of spudgun information]

Spark gap

2005-11-09T03:29:56Z

1984:

A '''spark gap''' consists of two metal electrodes placed close to each other with a gap in between, where an electrical spark can jump. They are used for igniting the fuel in [[combustion cannon|combustion]] and [[hybrid cannon]]s. Spark gaps are normally made by screwing two bolts through the side wall of the chamber, at an angle that puts the tips of the screws close together. The screws should be mounted to keep the heads a good distance apart, to ensure that the spark will not jump between the heads outside the chamber. The distance must be small enough that the voltage from the ignition source can jump across it. The distance is about 1.1 mm/kV, this varies with the shape of the electrodes though, sharp points allow longer sparks than flat surfaces. It should be noted that the pressurized mixture of a hybrid will shorten the max spark length, so a hybrid spark gap should be a fair bit smaller than max spark length to ensure reliability.
Spark plugs can be used for spark gaps, and are especially useful in metal guns, where the chamber wall would short out the screws of an ordinary spark gap.
Two or more spark gaps can be connected in series to generate multiple sparks, as long as the width of the combined gaps is smaller than the maximum spark distance. Spark gaps can not be wired in parallel, since the spark will then only jump the smallest gap.
[[Spark strip]]s are a popular method of achieving multiple spark gaps.

Main Page

2005-11-09T03:12:16Z

1984:

[[What is a spudgun?]]

[[Combustion cannon]]s

[[Pneumatic cannon]]s

[[Hybrid cannon]]s

[[BB machine gun]]s

[[Cannon construction]]

[[Launcher configuration]]

[[Safety]]

[[Legal issues]]

[[History]]

This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. All of this is totally free so be happy and get on to registering and posting!

-PCGUY, maker of SpudFiles

==External links==

*[http://spud.davidimpavid.com How to build and fire a spudgun]
*[http://www.bavetta.com/aircannon.html Air Cannon Barrel Length Numerical Analysis]
*[http://www1.iwvisp.com/thehalls/ggdt Gas Gun Design Tool, simulation program for pneumatic guns]
*[http://www.spudfiles.com/Other/are_they_legal.php ATF Correspondence concerning spud guns]
*[http://www.spudfiles.com Spud Files (aka The Spud Cannon Database)]
*[http://www.spudtech.com Great source of spudgun information]

Main Page

2005-11-09T03:12:02Z

1984: Maybe we have our first banlist member here

[[What is a spudgun?]]

[[Combustion cannon]]s

[[Pneumatic cannon]]s

[[Hybrid cannon]]s

[[BB machine gun]]s

[[Cannon construction]]

[[Launcher configuration]]

[[Safety]]

[[Legal issues]]

[[History]]
This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. All of this is totally free so be happy and get on to registering and posting!

-PCGUY, maker of SpudFiles

==External links==

*[http://spud.davidimpavid.com How to build and fire a spudgun]
*[http://www.bavetta.com/aircannon.html Air Cannon Barrel Length Numerical Analysis]
*[http://www1.iwvisp.com/thehalls/ggdt Gas Gun Design Tool, simulation program for pneumatic guns]
*[http://www.spudfiles.com/Other/are_they_legal.php ATF Correspondence concerning spud guns]
*[http://www.spudfiles.com Spud Files (aka The Spud Cannon Database)]
*[http://www.spudtech.com Great source of spudgun information]

Pressure gauge

2005-11-07T03:12:59Z

1984:

A '''pressure gauge''' is an instrument for measuring the pressure of gasses and liquids. It usually consists of a closed coiled tube connected to the chamber or pipe in which pressure is to be sensed. As the pressure increases the tube will tend to uncoil. This motion is transferred through a link to a gear train connected to an indicating needle, which indicated the pressure on a circular scale at the front of the gauge. The input of a typical pressure gauge is either a hose barb or male pipe thread. In the case of male pipe threads, you will need to [[tapping|tap]] a hole.

Pressure gauges are made for different maximum pressures, though they all typically can measure from 0 psi and upwards. It's important to choose a gauge that can handle the desired pressure. A gauge made for much higher pressure than needed will work, but with lower resolution and accuracy.

Pressure gauges are mainly used to indicate chamber pressure on [[Pneumatic cannon|pneumatic]] and [[hybrid cannon]]s, meter pressure on [[fuel meter]]s, peak pressure in some hybrids (in conjunction with a check valve), and tank pressure on [[bulk tank regulator]]s and [[compressor]]s. Some regulators have built-in gauges for output pressure, negating the need for a separate gauge.

The pressure indicated by the gauge is measured in comparison to atmospheric pressure, if this needs to be indicated, "gauge" or "g" is added to the unit of measure, for example "100 [[psi]] gauge" or "100 psig".

Tapping

2005-11-01T22:02:54Z

1984:

[[Image:Tap_set.gif|right|thumb|250ps|A set of pipe taps]]'''Tapping''' is the process of cutting [[thread]]s on the inside diameter of a hole with a tool called a tap. It is used to thread holes for mounting:
*[[Pressure gauge]]s
*[[Fuel meter]]s
*Electrodes (Bolts)
*[[Safety valve]]s
*Other

===Types of threads===

There are a few diffent thread systems that are used in spudgun construction

*[[NPT]] (National Pipe Taper)
*BSP (British Standard Pipe)
*NF (National Fine)
*NC (National Course)

===The process===

#Mark and drill an appropriatly sized hole
#*The hole should be in an area where fittings or pipe overlap (double thickness)
#*Find correct hole size with a [http://www.engineersedge.com/tap_drill_chart.htm Tap/Drill Chart]
#Insert the tap into the tap wrench
#*If you don't have a tap wrench, a normal crescent wrench can be used
#Cut the threads
#*Be careful to keep the tap straight or you will end up with crooked threads
#*If cutting anything other than plastic, use a cutting fluid to lubricate the tool
#*Apply downward pressure while slowly turning the tap clockwise 180 degrees, then back out 90 degrees counterclockwise to clear the chips
#*For tapered threads, stop as soon as the entire length of the hole is threaded
[[Category:Construction methods]]

Barrel

2005-10-28T01:22:17Z

1984:

The '''barrel''' is the pipe used to launch the projectile, and is, along with the [[chamber]], the only component found in all launchers. The diameter determines what projectiles will fit in the launcher, and the length affects how much energy is transferred to the projectile.

Modifications and improvements to the basic barrel include [[sleeving]], [[rifled barrel|rifling]], [[hop-up]]s and flatline barrels.

There are many diameters of barrels popular in spudding, below are some that fit certain ammo:

* 4.5mm brakeline - fits bbs, good for [[BBMGs]]
* 6mm brakeline - fits airsoft bbs, a commonly used ammo in BBMGs.
* 3/4" CPVC, 3/4" sch 80 PVC (looser fit), or 3/4" sch 120 PVC - fits .68" paintballs
* 1/2" sch 40 PVC - fits AA batteries, marbles.
* 3/4" sch 40 PVC - fits 12g [[CO2 cartridge]]s, C batteries.
* 1" sch 40 PVC - D batteries, smaller sized bouncy balls.
* 1.25" sch 40 PVC - fits somesort of battery
* 1.5" sch 40 PVC - a common size, good trade-off between power and potato usage. [http://www.spudtech.com/components.asp Available rifled from the [[SGTC]]]
* 1.5" sdr 21 PVC - fits golfballs. Traditionally [[sleeving|sleeved]] within SCH-80 PVC.
* 1.5" sdr 26 PVC - fits golfballs, but it is thinner than sdr 21, so the golfballs fit a little looser. Traditionally sleeved within 2" SCH-80 PVC.
* 2" sch 80 PVC fits sdr 21 and 26 pipe well. Also used as a golf ball barrel by itself, with the golf ball held in place by a rag patch, or other wadding. Also fits normal light bulbs! Details here: http://advancedspuds.com/concreteballs.htm
* 2.5" sch 40 PVC - fits tennis balls well.
* 3" sch 80 PVC - fits many drink bottles well.
* 3" sch 40 PVC - fits normal cans, and empty propane torch tanks

Chamber

2005-10-28T01:20:23Z

1984: typo fixed

The '''chamber''' or '''reservoir''' is the power source of a spudgun. It is, along with the [[barrel]], the only component found in all launchers. In [[combustion cannon]]s, the chamber contains the flammable fuel/air mixture, and in [[pneumatic cannon]]s it contains the compressed gas. The chamber is connected to the barrel either directly or through a valve, to propel the projectile when the energy is released. The chamber is often the part of the launcher that is subjected to the highest stress, and it's important that it is well constructed. It is also the part where the most accessories are connected, especially combustion launchers can have a multiple holes to accommodate [[spark gap]]s, [[chamber fan]]s, [[fuel meter]]s and for [[venting]].

{{stub}}

Talk:Cannon construction

2005-10-26T20:42:36Z

1984:

What is NSF-61?

Talk:Cannon construction

2005-10-26T20:42:14Z

1984:

What is SDR-61?

Main Page

2005-10-26T00:03:34Z

1984:

This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. And all of this, is totally free so be happy and get on to registering and posting!

-PCGUY, maker of spudfiles

Note - This page (Main Page) is open for editing!

[[What is a spudgun?]]

[[Combustion cannon]]s

[[Pneumatic cannon]]s

[[Hybrid cannon]]s

[[BB machine gun]]s

[[Cannon construction]]

[[Launcher configuration]]

[[Legal issues]]

[[History]]

Check valve

2005-10-25T23:45:21Z

1984:

A '''check valve''' is a valve designed to only allow a fluid (liquid or gas) to flow in one direction.

{{stub}}

Combustion

2005-10-25T23:27:43Z

1984:

The term "combustion" can refer to either
*A [[combustion cannon]], a launcher powered by a combustion reaction
*The [[combustion process]] itself
{{disambig}}

Sweating

2005-10-25T23:24:28Z

1984:

'''Sweating''' is a method of joining metal tubing and fittings, usually of copper and brass. Solder fittings are also called capillary fittings, because of the capillary action that draws solder into the joint.

The heat source used for sweating is normally a propane blowtorch, but a high wattage soldering iron can also be used. The solder should be flux-free, alloys such as tin-silver or tin-antimony made specifically for pipe can be used, they are environmentally friendly and generally stronger than tin/lead solder.

To prepare the pipe for soldering, the surfaces to be soldered must first be cleaned. This can be done with fine sandpaper, abrasive pads and/or a wire brush. For optimal strength, the polishing direction should be perpendicular to the forces on the resulting joint, so the small grooves created by the polishing increase the friction between the parts.

Next, a layer of flux paste is applied to the surfaces that are to be soldered. this dissolves oxides and similiar impurities, and helps the solder flow and stick to the pipe. Excess flux can be wiped off before soldering, and any remains should be cleaned off afterwards, since flux remaining in the pipe can lead to corrosion. Alcohol works well for this purpose.

The parts that are to be soldered are then clamped down and heated with the torch. Ideally the joint should be mounted so the seam is vertical, this will let solder flow down both sides and any excess will drip out at the bottom.

The flame should be applied to both parts of the joint, to ensure that they both recieve enough heat to melt the solder. When the flame turns green where it touches the metal, or the solder melts when touching it, the metal is hot enough. Solder is then applied to the gap near the top, and will flow into and fill the joint. The joint is full when solder is visible around the rim, or when a drop starts to form at the bottom of the joint. Excess solder can be wiped off using a wet cotton cloth (synthetic cloth may melt).

The parts will become very hot, even well away from the soldering area, so they should be kept away from materials that could be damaged from the heat. The surface beneath may be subjected to dripping soldering paste and solder, and need to be able to withstand this. Wood will work but may get scorch marks and grease spots, metal or concrete is recommended.

When soldering several joints close to each other, it is recommended to solder them all in the same operation, to avoid re-melting of previously made joints.

It is advisable to have a bowl of cold water nearby, in case of burns or fires, or to cool down parts if needed. The finished joints should be left to cool naturally if possible.
[[Category:Construction methods]]

Union

2005-10-25T23:22:46Z

1984:

[[Image:Union.jpg|right|thumb|250px|A diagram of a union]]A '''union''' is a fitting that allows a threaded joint without requiring the joined pipes to be rotated. They are usually made of either steel, brass or PVC. Most unions are pressure rated. A union consists of two male threaded pieces, connected by a threaded oversized nut. the pipe couplings are either socket-weld, capillary (for brass) or threaded. PVC unions have been known to blow up when used in hybrids, Boogieman and LuckyThirteen13's PVC unions have exploded before. Variations on the union exist, like 90 degree unions. Alternatives to unions include [[flange]]s and [[cam and groove]] couplings.

[[Category:Construction materials]]

==External Links==
*Unions on [http://www.mcmaster.com/ McMaster]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=plasticppf&FT_138=899 Plastic Unions]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Stainless Unions]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Iron/Steel Unions]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Aluminum Unions]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Brass Unions]

Union

2005-10-25T23:22:12Z

1984:

[[Image:Union.jpg|right|thumb|250px|A diagram of a union]]A '''union''' is a fitting that allows a threaded joint without requiring the joined pipes to be rotated. They are usually made of either steel, brass or PVC. Most unions are pressure rated. A union consists of two male threaded pieces, connected by a threaded oversized nut. the pipe couplings are either socket-weld, capillary (for brass) or threaded. PVC unions have been known to blow up when used in hybrids, Boogieman and LuckyThirteen13's PVC unions have exploded before. Variations on the union exist, like 90 degree unions. Alternatives to unions include [[flange]]s and [[cam and groove]] couplings.

[[Category:Construction materials]]

==External Links==
*Unions on [hhtp://www.mcmaster.com McMaster]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=plasticppf&FT_138=899 Plastic Unions]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Stainless Unions]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Iron/Steel Unions]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Aluminum Unions]
**[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Brass Unions]

Union

2005-10-25T23:17:28Z

1984:

[[Image:Union.jpg|right|thumb|250px|A diagram of a union]]A '''union''' is a fitting that allows a threaded joint without requiring the joined pipes to be rotated. They are usually made of either steel, brass or PVC. Most unions are pressure rated. A union consists of two male threaded pieces, connected by a threaded oversized nut. the pipe couplings are either socket-weld, capillary (for brass) or threaded. PVC unions have been known to blow up when used in hybrids, Boogieman and LuckyThirteen13's PVC unions have exploded before. Variations on the union exist, like 90 degree unions. One alternative to a union is a [[flange]].
[[Category:Construction materials]]

==External Links==
*[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=plasticppf&FT_138=899 Plastic Unions on McMaster]
*[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Stainless Unions on McMaster]

Union

2005-10-25T23:16:25Z

1984:

[[Image:Union.jpg|right|thumb|250px|A diagram of a union]]A '''union''' is a fitting that allows a threaded joint without requiring the joined pipes to be rotated. They are usually made of either steel, brass or PVC. Most unions are pressure rated. A union consists of two male threaded pieces, connected by a threaded oversized nut. the pipe couplings are either socket-weld, capillary (for brass) or threaded. PVC unions have been known to blow up when used in hybrids, Boogieman and LuckyThirteen13's PVC unions have exploded before. Variations on the union exist, like 90 degree unions.
[[Category:Construction materials]]

==External Links==
*[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=plasticppf&FT_138=899 Plastic Unions on McMaster]
*[http://www.mcmaster.com/nav/enter.asp?psearch=FAM=ssppf&FT_138=899 Stainless Unions on McMaster]

Union

2005-10-25T23:14:24Z

1984:

Golf ball

2005-10-25T21:11:59Z

1984:

[[Image:Golf_ball.jpg|200px|right|]]Golf balls are commonly used as ammo in spudguns for a few reasons

*Uniform in shape and size
*Aerodynamic
*Availability

==Barrels==

Golf balls fit perfectly in SDR 21 [[PVC]] pipe, but because of its thin walls, it should be sleeved inside 2" SCH 80.

{{stub}}

Golf ball

2005-10-25T20:57:47Z

1984:

[[Image:Golf_ball.jpg|right|thumb|250px]]Golf balls are commonly used as ammo in spudguns for a few reasons

*Uniform in shape and size
*Aerodynamic
*Availability

==Barrels==

Golf balls fit perfectly in SDR 21 [[PVC]] pipe, but because of its thin walls, it should be sleeved inside 2" SCH 80.

{{stub}}

File:Golf ball.jpg

2005-10-25T20:50:12Z

1984: A golf ball

A golf ball

What is a spudgun?

2005-10-25T20:46:04Z

1984:

'''Spud guns''', '''potato cannons''', or '''produce accelerators''' are all recreational launching devices usually made of [[PVC]] 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: [[mandarin orange|mandarins]], [[potato]]es, [[tennis ball]]s, and [[golf ball]]s. 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.

Talk:Diaphragm valve

2005-10-25T02:35:51Z

1984:

I think we should change the diagram to reflect the fact that mostdiaphrams havea center reinforced by a pair of washers, rather than being flexible as is currently suggested. If it were built as shown, the center of the diaphram would likely rupture or the entire piece would be blown out the barrel.

PVC pipe

2005-10-25T00:39:08Z

1984:

'''PVC pipe''' and fittings is the most common material for spudgun construction. It is cheap, lightweight and availble in a wide range of dimensions and ratings. PVC is usually joined by [[solvent welding]], which is easy to do and requires no special tools. Threaded fittings are also used, but then solvent welded to the pipe. PVC is easy to machine, and parts are sometimes [[bushing modification|customized]] to fit a certain purpose.

One of the main disadvantages of PVC is that it becomes brittle in cold weather, which may lead to chamber failure, especially in pneumatic launchers. When PVC fails under pressure it breaks into sharp shards, which are propelled at high velocity. Because of this danger PVC pipe is not rated for use with pressurized gasses, and the use in spudguns is to be regarded as outside of specifications. When proper precautions are taken, it is still very safe to use.

===Naming Conventions===

====Schedule====
Schedule is a method of denoting pipe demintions with a standardided set of nominal sizes. Note that this is a ''size'' convention, and does not neccessarily denote a pressure rating. [http://harvel.com/pipepvc-sch40-80-dim.asp Harvel] has tables of dimentions for SCH40 and SCH80 pipe sizes.

====SDR==== 

SDR pipe has the same O.D. as Schedule pipe, but with different pipe I.D. All SDR pipe in a series has the same ratio of O.D to wall thickness throughout the sizes, and thus has the same pressure rating. All SDR pipe is rated for pressure, but becuase it often has relatively thin walls, it should be [[sleeving|sleeved]] or otherwise reinforced before use. [http://harvel.com/pipepvc-sdr-dim.asp Harvel]
has charts of dimentions and pressure ratings for SDR pipe.

{{Stub}}

Tapping

2005-10-24T23:27:57Z

1984:

[[Image:Tap_set.gif|right|thumb|250ps|A set of pipe taps]]'''Tapping''' is the process of cutting [[thread]]s on the inside diameter of a hole with a tool called a tap. It is used to thread holes for mounting:
*[[Pressure gauge]]s
*[[Fuel meter]]s
*Electrodes (Bolts)
*[[Safety valve]]s
*Other

===Types of threads===

There are a few diffent thread systems that are used in spudgun construction

*[[NPT]] (National Pipe Taper)
*BSP
*NF (National Fine
*NC (National Course)

===The process===

#Mark and drill an appropriatly sized hole
#*The hole should be in an area where fittings or pipe overlap (double thickness)
#*Find correct hole size with a [http://www.engineersedge.com/tap_drill_chart.htm Tap/Drill Chart]
#Insert the tap into the tap wrench
#*If you don't have a tap wrench, a normal crescent wrench can be used
#Cut the threads
#*Be careful to keep the tap straight or you will end up with crooked threads
#*If cutting anything other than plastic, use a cutting fluid to lubricate the tool
#*Apply downward pressure while slowly turning the tap clockwise
#*For tapered threads, stop as soon as the entire length of the hole is threaded

Tapping

2005-10-24T23:26:28Z

1984: typo

[[Image:Tap_set.gif|right|thumb|250ps|A set of pipe taps]]'''Tapping''' is the process of cutting threads on the inside diameter of a hole with a tool called a tap. It is used to thread holes for mounting:
*[[Pressure gauge]]s
*[[Fuel meter]]s
*Electrodes (Bolts)
*[[Safety valve]]s
*Other

===Types of threads===

There are a few diffent thread systems that are used in spudgun construction

*[[NPT]] (National Pipe Taper)
*BSP
*NF (National Fine
*NC (National Course)

===The process===

#Mark and drill an appropriatly sized hole
#*The hole should be in an area where fittings or pipe overlap (double thickness)
#*Find correct hole size with a [http://www.engineersedge.com/tap_drill_chart.htm Tap/Drill Chart]
#Insert the tap into the tap wrench
#*If you don't have a tap wrench, a normal crescent wrench can be used
#Cut the threads
#*Be careful to keep the tap straight or you will end up with crooked threads
#*If cutting anything other than plastic, use a cutting fluid to lubricate the tool
#*Apply downward pressure while slowly turning the tap clockwise
#*For tapered threads, stop as soon as the entire length of the hole is threaded

Cannon construction

2005-10-24T23:25:57Z

1984:

It is important to construct your launchers with care. This includes:

* Using pressure rated (NSF-PW or NSF-61) fittings and pipe, especialy in a [[pneumatic cannon]].
* [[Solvent welding]] [http://www.burntlatke.com/weld.html correctly]
* Using pipe of the proper pressure rating, eg. sch 80 in a [[Hybrid Cannon]].
* Only [[tapping|tap]] though a double layer of pipe where the pipe and a fitting is joined(for bolts, pressure gauges) .

Under no circumstances WHAT SO EVER should you use [[cell-core]] or unsleeved thinwall [[PVC]] pipe.

Cannon construction

2005-10-24T23:25:42Z

1984:

It is important to construct your launchers with care. This includes:

* Using pressure rated (NSF-PW or NSF-61) fittings and pipe, especialy in a [[pneumatic cannon]].
* [[Solvent welding]] [http://www.burntlatke.com/weld.html correctly]
* Using pipe of the proper pressure rating, eg. sch 80 in a [[Hybrid Cannon]].
* Only [[taping|tap]] though a double layer of pipe where the pipe and a fitting is joined(for bolts, pressure gauges) .

Under no circumstances WHAT SO EVER should you use [[cell-core]] or unsleeved thinwall [[PVC]] pipe.

Cannon construction

2005-10-24T23:25:04Z

1984:

It is important to construct your launchers with care. This includes:

* Using pressure rated (NSF-PW or NSF-61) fittings and pipe, especialy in a [[pneumatic cannon]].
* [[Solvent welding]] [http://www.burntlatke.com/weld.html correctly]
* Using pipe of the proper pressure rating, eg. sch 80 in a [[Hybrid Cannon]].
* Only [[tap]] though a double layer of pipe where the pipe and a fitting is joined(for bolts, pressure gauges) .

Under no circumstances WHAT SO EVER should you use [[cell-core]] or unsleeved thinwall [[PVC]] pipe.

BB machine gun

2005-10-24T23:22:42Z

1984:

A '''BB machine gun''' is a device designed to shoot large numbers of small diameter ammo, typicaly steel BBs or plastic airsoft bbs. Their air consumption is huge, rendering them practicaly non-portable; even a sizable tank would be emptied in a couple seconds.

There are a couple common designs:
* A [[cloud chamber]] agitates the projectiles by blowing the air stream up through them. The agitated bbs then get sucked into the barrel.

* A [[vortex block]] blows the bbs around and around the inside of larg-ish diameter hole, which has a tangetal hole leading to the barrel drilled in it.

Main Page

2005-10-24T23:21:37Z

1984:

Do you really know what this website is about? Do you? This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. And all of this, is totally free so be happy and get on to registering and posting!

-PCGUY, maker of spudfiles

Note - This page (Main Page) is open for editing!

[[What is a spudgun?]]

[[Combustion cannon]]s

[[Pneumatic cannon]]s

[[Hybrid cannon]]s

[[BB machine gun]]s

[[Cannon construction]]

[[Launcher configuration]]

[[Legal issues]]

[[History]]

Combustion reaction

2005-10-24T22:33:27Z

1984:

In chemistry, a '''combustion reaction''' is the exothermic reaction of a fuel with an oxidizer. In spudguns, this is the reaction that fuels combutions and hybirds. It is ussually a reaction between a hydrocarbon ([[propane]] or [[butane]]) and atmospheric O2, to produce CO2 and H2O

{{stub}}

Combustion reaction

2005-10-24T22:32:48Z

1984:

In chemistry, a '''combustion reaction''' is the exothermic reaction of a fuel with an oxidizer. In spudguns, this is the reaction that fuels combutions and hybirds. It is ussually a reaction between a hydrocarbon ([[propane]] or [[butane]]) and atmospheric oxygen, to produce CO2 and H2O

{{stub}}

Combustion

2005-10-24T22:29:48Z

1984:

The term "combustion" can refer to either
*A [[combustion cannon]], a launcher powered by a combustion reaction
*The [[combustion reaction]] itself
{{disambig}}

Cellular core pipe

2005-10-24T21:51:56Z

1984:

#REDIRECT [[Cell-core]]

Cellular core pipe

2005-10-24T21:51:21Z

1984:

#REDIRECT [[Cell-Core]]

Starting fluid

2005-10-24T21:49:29Z

1984:

'''Starting fluid''' is normally known as ether, diethyl ether, or ethyl ether. All types are powerful, some people beleive they produce more power than propane. Ethers are incredibly easy to over-fuel however. the upper flammability limit is about the same as the LOWER flammability limit of propane.

Some starter fluids contain oil, which can gunk up the chamber and disable [[lantern sparker]]s. It may also be corrosive to certain plastic and rubber materials. The fluid can be tested for oil by spraying some on a piece of paper, any oil will leave a grease stain after the ether has evaporated.

[[category:fuels]]

Starting fluid

2005-10-24T21:49:16Z

1984:

'''Starting fluid'''' is normally known as ether, diethyl ether, or ethyl ether. All types are powerful, some people beleive they produce more power than propane. Ethers are incredibly easy to over-fuel however. the upper flammability limit is about the same as the LOWER flammability limit of propane.

Some starter fluids contain oil, which can gunk up the chamber and disable [[lantern sparker]]s. It may also be corrosive to certain plastic and rubber materials. The fluid can be tested for oil by spraying some on a piece of paper, any oil will leave a grease stain after the ether has evaporated.

[[category:fuels]]

Gas Gun Design Tool

2005-10-24T21:48:14Z

1984:

Hall Consulting's '''Gas Gun Design Tool''' is a simulation program to aid the design of [[pneumatic cannon]]s.

[http://www1.iwvisp.com/thehalls/GGDT/index.html Homepage]

Schrader valve

2005-10-24T21:39:08Z

1984:

A '''schrader''' valve, often called a "tire valve", "tank valve" or "sniffler valve" because schrader is a brand name, is used in [[hybrid launcher|hybrid]] and [[pneumatic launcher]]s to allow you to fill them with air. They are also used, less frequently, in [[combustion launcher]]s, to allow you to [[venting|vent]] them.

They accept the standard air chuck used to fill tires, allowing you to fill them with a standard bicycle pump.
Alternative valves exist, most notably the [[quick disconnect]] which is more expensive, but has a higher amount of flow.

[http://en.wikipedia.org/wiki/Schraeder_valve more info]

[[category:valves]]

Sprinkler valve

2005-10-24T21:28:40Z

1984:

The next step up from a [[ball valve]], this is essentially a commercially produced [[diaphragm valve]]. However, they are unfortunately designed to open relatively slowly to prevent "water hammer". The performance can be improved by replacing the stock solenoid-valve vent with a [[pilot valve]] with more flow. Most often this is a blow gun, although for larger valves a ball valve or even a smaller sprinkler valve can be used. This operation is often called [[sprinkler valve modification|modding]] the valve.

===Troubleshooting===
If you are having problems with your sprinkler valve, these are some things to try
====Valve "Honks"====
You need a larger pilot valve. For more information, see [[honking]].

====Valve won't seal====
If your valve leaks air out the barrel, you should disassemble it and clean the diaphram and seat. Check for any plastic chips that may have entered the valve. Lube the diaphram and seat with lithium grease to promote a seal.

====Valve won't open====

[[category:valves]]

Sprinkler valve modification

2005-10-24T21:16:01Z

1984:

This refers to '''modifying''' a [[sprinkler valve]] to actuate via a pilot valve with a higher flow then the solenoid—typicaly a blowgun, although larger valves (1.5-2" and up) require something with more flow to preform well. The larger vent decreases [[opening time]], and does not require batteries like the stock solenoid. A step by step tutorial of the process is available at [http://www.spudfiles.com/forums/viewtopic.php?t=305 Spudfiles]

The faster the pilot valve, the faster the actuated valve will open. This means that performance can be increased by using a [[QEV]], which offers the additional bennifit of eliminating the human variable. This should yield more consistant muzzle velocities.

Another modification that can be made is enlarging the pilot leak hole. If the Sprinkler valve is opened it contains a large diameter rubber disk (called the diaphragm). About 1/2-1" in somewhere around the diaphragm (in a oftenly used [http://www.orbitonline.com/index.cfm?fa=watermaster.product&productid=201 Orbit Watermaster] sprinkler valve) will be a small white plasic piece poked through the diaphragm. If this piece is removed, the pilot area above the diaphragm will be pressurized instantly while the cannon is being filled, and so the valve will be more sensitive and will (in some instances) seat better.

[[category:valves]]

Sprinkler valve modification

2005-10-24T21:15:46Z

1984:

This refers to '''modifying''' a [[sprinkler valve]] to actuate via a pilot valve with a higher flow then the solenoid—typicaly a blowgun, although larger valves (1.5-2" and up) require something with more flow to preform well. The larger vent decreases [[opening time]], and does not require batteries like the stock solenoid. A step by step tutorial of the process is available at [http://www.spudfiles.com/forums/viewtopic.php?t=305 Spudfiles]

The faster the pilot valve, the faster the actuated valve will open. This means that performance can be increased by using a [[QEV]], which offer the additional bennifit of eliminating the human variable. This should yield more consistant muzzle velocities.

Another modification that can be made is enlarging the pilot leak hole. If the Sprinkler valve is opened it contains a large diameter rubber disk (called the diaphragm). About 1/2-1" in somewhere around the diaphragm (in a oftenly used [http://www.orbitonline.com/index.cfm?fa=watermaster.product&productid=201 Orbit Watermaster] sprinkler valve) will be a small white plasic piece poked through the diaphragm. If this piece is removed, the pilot area above the diaphragm will be pressurized instantly while the cannon is being filled, and so the valve will be more sensitive and will (in some instances) seat better.

[[category:valves]]

Sprinkler valve modification

2005-10-24T21:15:21Z

1984:

This refers to '''modifying''' a [[sprinkler valve]] to actuate via a pilot valve with a higher flow then the solenoid—typicaly a blowgun, although larger valves (1.5-2" and up) require something with more flow to preform well. The larger vent decreases [[opening time]], and does not require batteries like the stock solenoid. A step by step tutorial of the process is available at [http://www.spudfiles.com/forums/viewtopic.php?t=305 Spudfiles]

The faster the pilot valve, the faster the actuated valve will open. This means that performance can be increased by using [[QEV]]s, which offer the additional bennifit of eliminating the human variable. This should yield more consistant muzzle velocities.

Another modification that can be made is enlarging the pilot leak hole. If the Sprinkler valve is opened it contains a large diameter rubber disk (called the diaphragm). About 1/2-1" in somewhere around the diaphragm (in a oftenly used [http://www.orbitonline.com/index.cfm?fa=watermaster.product&productid=201 Orbit Watermaster] sprinkler valve) will be a small white plasic piece poked through the diaphragm. If this piece is removed, the pilot area above the diaphragm will be pressurized instantly while the cannon is being filled, and so the valve will be more sensitive and will (in some instances) seat better.

[[category:valves]]

Union

2005-10-24T20:19:23Z

1984:

Union

2005-10-24T20:17:35Z

1984:

[[Image:Union.jpg|right|thumb|250px|A diagram of a union]]A union is usually made of either steel, brass or PVC. Most unions are pressure rated. A union consists of two male threaded pieces, connected by a threaded oversized nut. the pipe couplings are either socket-weld, capillary (for brass) or threaded. PVC unions have been known to blow up when used in hybrids, Boogieman and LuckyThirteen13's PVC unions have exploded before. Variations on the union exist, like 90 degree unions.

File:Union.jpg

2005-10-24T20:15:45Z

1984: A diagram of a PVC union

A diagram of a PVC union

Hybrid cannon

2005-10-24T20:06:38Z

1984:

A '''hybrid''' launcher consists of seven basic elements:

*High pressure combustion chamber
*Pressure-triggered main valve (usually a [[burst disk]])
*[[Barrel]]
*Fuel system (usually [[fuel meter|metered propane]])
*Air filling valve
*powerfull [[Ignition source]]
*One or more [[pressure gauge]]s

A hybrid is a type of spudgun that combines principles of the [[combustion cannon|combustion]] and [[pneumatic cannon|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 lever coupling]] or [[union]] is used to hold the burst disk in place. The operator then loads projectile into the barrel, adds fuel to the combustion chamber, and then adds pressurized air. The amount of air depends on how much fuel was added, and is calculated to achieve a [[stoichiometric]] fuel/air ratio in the chamber. 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+ [[Pressure gauge|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 every where. Therefore utmost care must be taken with these launchers.