Spud Shot Spud Guns - Instructions

Potato Cannon Operation Instructions

SS-300 Propane Cannon

First let me tell you that its real easy to operate this cannon, in fact it is easier and safer than typical hairspray potato cannons. There is no need to open the rear of the chamber to expose yourself to accidental burns by visually checking the ignition spark with the chamber opened.

First thing you want to do before you even receive your cannon is to get a disposable Bernz-o-Matic Propane tank, and a set of 9v batteries. The Propane tank is your source of fuel and is located directly underneath the chamber portion of your cannon. The 9 volt batteries are to power the chamber fan that exhausts the cannon prior to firing. The operation of all these goodies will be explained shortly, but first let me go over loading the spud and the fueling system.

Loading your cannon is really simple, there are two ways of doing this, either way is fine. The first method is called muzzle loading. Muzzle loading is where you simply ram the potato down the end of the barrel using a ram rod. Breech loading is where you unscrew the barrel from the chamber and insert the potato in the back end of the barrel, also called the breech. First, load your potato in the barrel and then proceed to fuel the cannon.

Onboard Propane tank holder with magnetic tank holder, pressure regulator, and meter pipe

The fuel system of the SS-300 may look complicated but its actually simple in design. First start by taking the modified torch adapter with the round dial(making sure it is in the OFF position) and screw it into the tank like shown in the above picture. The tank will slide all the way into the tank holder and a ceramic magnet is fastened in the base of it will prevent the tank from sliding out.
The main valve is connected to a pressure regulator via a hose (blue in the picture). Directly after the pressure regulator is a pair of ball valves and a section of 3/8" brass pipe.

Close up of fan box, meter pipe and ball valves

Shown in the picture above is the fan box and its switch. Inside the clear box are two 9 volt battery clips and a push button switch to turn the fan on. The fan is used in conjunction with the meter pipe to fuel and exhaust the cannon safer and more accurate than your typical combustion basted potato cannon.

There are three valves used to fuel the cannon. Make sure that the valves on the meter pipe are in the off position (perpindicular to the meter pipe as shown in the above picture) and turn the round valve on the modified torch head adapter until the gauge on the regulator climbs to 81 PSI. If it does not reach 81 PSI the regulator can be adjusted by the knob opposite the gauge. Next you must open the first valve (next to the regulator) and watch the pressure gauge, it should drop and come right back to 81 psi. Then the first valve is closed sealing a measured volume of propane in the pipe between the two ball valves. The valve closest 90 degree elbow fitting (rear of chamber) is opened next which dumps the propane into the cannon. You want to open this valve slow, and then close it.

NOW you must proceed with caution because your spud gun is armed and ready to fire. At this point you should already be facing your target with any people or animals away from your line of fire.

The trigger is located at the tip of the handle and is ment to be squeezed by your thumb, holding the cannon at your hip like a gatling gun.

Now after you have fired your cannon you will need to exhaust the cannon using the fan. The fan must be turned on for at least 30 seconds to fully exhaust the burnt propane and replace the spent oxygen. Remember that the metering system will only work if there is sufficent oxygen in the chamber.

How the metering system works:

Propane gas is measured in pressure and volume. We can assume the pressure by what is shown on the pressure regulator gauge. The next thing to figure out is the volume. Typically brass water pipe has a standard inner dimension. By taking the length and diameter of the pipe we can get the inside volume of the meter pipe. You could also measure using a liquid (like water) and then measure the volume of water. This is extremly important to accuratly gauge how much propane we need to dump into the chamber.

The correct fuel to air ratio for a propane fired cannon is 4% propane gas to 96% air (assuming atmospheric pressure is around 14 PSIA, and the available O2 in the air is around 20%) . The higher the elevation the less propane you will need to dump into the cannon to get the correct the ratio.

Advanced Techniques:

Once you get a few shots under your belt, try some advanced techniques with your cannon such as:

Changing the setting on the pressure regulator to try more and less fuel. Remember, you might have to calibrate it a little bit at first depending on your elevation and oxygen saturation in the air where you live.

Try using the fan to mix up the propane and air AFTER you dump the fuel in (last valve) Before you fire. Dont forget to also use at least 30 seconds of fan time after each shot as well to refresh oxygen inside the cannon

and of course

dont click the ignition on the gun while looking down the barrel, or in the back of an opened chamber

dont shoot people, public places/things

dont get in trouble with one! Promoting safe spud gun usage keeps it legal and may lift restrictions on some places where potential spudders live! Doing unsafe stuff is not funny in the spudding community

High Voltage Ignition System

Instructions

DANGER: This is a high voltage ignition system capable of producing over 100,000 volts (10kV). It has a low current so it wont kill you, but I have been zapped by these things countless times and I can tell you...its not that pleasant. It is considered non-lethal however people with a pacemaker or very serious heart conditions should take extreme caution with its use.

1. Before you get started make sure you have a high grade 9v battery, dollar store throw away batteries probably wont work good or even work at all. I reccomend a pair of rechargable 9v batteries.

2. The four wires that come from the box are the ignition wires, and handle switch wires. The ignition wires will be placed in the corners of the narrow end of the box through two seperate holes, these are the wires you attach to your electrode setup. DO NOT REMOVE the tape on the end of these two wires, this is essential to testing which will be explained later. The two wires coming from the middle of the long side of the box are the handle switch lines, they will be spliced with bare wire showing.

3.Unscrew the four cover screws and remove the top, don't pull too hard, wires are attached to the underside of the switch. If you need more room to replace batteries you can detach and reattach the wires from the ignition safety switch, however this shouldn't be necessary.

4.Put the clip on the battery and place the battery inside the box into its holder.

5. Tuck the wires nice and neat inside the box, replace the cover and screws.

6. TESTING:

The ignition wires will be placed in the corners of the narrow end of the box through two seperate holes(or in the same hole for custom setups) these are the wires you attach to your electrode setup. DO NOT REMOVE the tape on the end of these two wires. These wires will not be spliced, no bare wire showing. Those two wires need to be very close to maintain a small gap for the first test and do not need to have wire exposed yet.

The two wires coming from the middle of the long side of the box are the handle switch wires, they will be spliced with bare wire showing.

To do the initial test, make sure you have read and completed the previous steps. Now set the ignition box on a table. Position the Ignition Wires away from your hands or body but make sure you can see the taped end with the two tips close to each other. Flip the cover on the ignition safety switch (mounted to the box) and flip the switch. The unit will not function without this safety switch in the ON position, think of it as the safety on your pistol, or rifle, as it will be the safety switch for your combustion cannon. A light on the tip of the switch should light up red to indicate the ON position. Position the box so that the ignition wires are away from your body, you really dont want to get zapped. The handle switch wires are low voltage so handling them is not a safety issue. Hold the switch wires and touch the two wires together for a breif second.
ZAP!
If you have sparks you are all ready to start putting it on your cannon!

Mounting, Operating, etc.

Advanced operators can skip this if necessary.
First thing you should know about your ignition system is that it is not designed for continuous operation. Only discharge the unit for one to two seconds at a time. Continuously holding the trigger for a longer duration will damage the unit and will significantly shorten its lifespan.

The easiest way of attaching this to your cannon is by using velcro tape. It is cheap and allows you to swap boxes easily.

Most people like to use a dual ignition setup when using a high voltage ignition system. It is very easy to do, all you have to do is wire the ignition circuit in a loop, or a series circuit, not parallel.

(IGNITOR)------o o-----------o o------(BACK TO IGNITOR)

Use loop terminals (the clamp on wire ones) and some decent length machine screws for your electrodes. DO NOT exceed 1/4" spark gap. Setting larger spark gaps will not increase performance and will damage the unit. Reccomended 1/8" for multiple spark gaps.

There is a switch included with the ignition system along with some wire terminals attached to it.
Insert the wires into the terminals, clamp the terminals/wires (shorten if necessary) and clip them into the back of the switch if using the switch provided.

Mount this switch anywhere you like on your cannon, in a cool handle, let it hang, attach more wire for remote igntion, or even attach an infared eye for remote control ignition, be creative!

Possibilities soon to come in the future: Custom all-in-one fan controller box AND stungun ignition. Modified propane attachments, custom meter pipes and valve systems, automatic solenoid valves, portable and onboard propane setup. Ammunition section: rubber bouncy balls, plastic balls (high density), injection molded ammunition, rifled slugs, pvc rockets, breech loading barrels, bolt action barrels. More air cannons and air cannon accessories. Piston valves, ball valves, sch. 80 unions, precut burst disks, safety blowoff valves, flow regulators, check valves, custom air gauges.

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