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Page No.
List of Illustrations ---------------------------------------------------------------------- 2-3
Introduction
Purpose --------------------------------------------------------------------------------------------- 4
Scope ------------------------------------------------------------------------------------------------ 4
Intended Users ------------------------------------------------------------------------------------ 4
Usage ------------------------------------------------------------------------------------------------ 4
Safety Information ---------------------------------------------------------------------------- 4-5
Process Description ----------------------------------------------------------------------- 6
Required Tools List ------------------------------------------------------------------------ 7
Materials List --------------------------------------------------------------------------- 8-11
Before You Begin ------------------------------------------------------------------------- 12
Directions
Assembling the Air Chamber ----------------------------------------------------------- 13-16
Assembling the Barrel ------------------------------------------------------------------------- 17
Assembling the Trigger Valve ----------------------------------------------------------- 18-21
Assembling the Receiver --------------------------------------------------------------------- 22
Final Assembly ----------------------------------------------------------------------------- 23-24Testing and Operation
Air Chamber Pressure Test ------------------------------------------------------------------- 25
Trigger Valve Test ------------------------------------------------------------------------- 25-26
Operation ---------------------------------------------------------------------------- 26
Launching A T-Shirt ----------------------------------------------------------------- 26
Future Options ---------------------------------------------------------------------- 27
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Page No.
Figure 1: Process Flow -------------------------------------------------------------------------- 6
Figure 2: Sch. 40 Example 1 ------------------------------------------------------------------- 8Figure 3: Sch. 40 Example 2 ------------------------------------------------------------------- 8
Figure 4: PVC Primer -------------------------------------------------------------------------- 12
Figure 5: Heavy Duty PVC Cement --------------------------------------------------------- 12
Figure 6: PVC Bonding Directions ---------------------------------------------------------- 12
Figure 7: Air Chamber (Step 2) ------------------------------------------------------------- 13
Figure 8: Air Chamber Bushings (Dry-Fit) ------------------------------------------------ 13
Figure 9: Air Chamber Bushings (Bonded) ----------------------------------------------- 14
Figure 10: Drilling Air Chamber Inlet ------------------------------------------------------ 14Figure 11: Thread Cutting Tool ------------------------------------------------------------- 14
Figure 12: Cutting Air Chamber Threads ------------------------------------------------- 14
Figure13: Applying Teflon Tape to Threads --------------------------------------------- 15
Figure 14: Air Chamber Inlet Nipple ------------------------------------------------------- 15
Figure 15: Pressure Gage and Schrader Valve Configuration ----------------------- 15
Figure 16: Assembled Air Chamber Inlet ------------------------------------------------- 15
Figure 17: Installed Air Chamber Inlet ---------------------------------------------------- 16
Figure 18: Drilling Air Chamber Cap ------------------------------------------------------- 16
Figure 19: Safety Pressure Valve ----------------------------------------------------------- 16
Figure 20: Completed Air Chamber ------------------------------------------------------- 16
Figure 21: Threaded Barrel Connector --------------------------------------------------- 17
Figure 22: Completed Barrel ---------------------------------------------------------------- 17
Figure 23: Unmodified Irrigation Valve --------------------------------------------------- 18
Figure 24: Electronic Actuator Removed ------------------------------------------------- 18
Figure 25: Removing Top Screws ---------------------------------------------------------- 19
Figure 26: Disassembled Irrigation Valve ------------------------------------------------ 19
Figure 27: Taping Valve Hole ---------------------------------------------------------------- 19
Figure 28: J-B WELD --------------------------------------------------------------------------- 19
Figure 29: Sealed Valve Cavity -------------------------------------------------------------- 20
Figure 30: Cutting Valve Body Threads --------------------------------------------------- 20
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List of Illustrations (continued)
Figure 31: Valve Nipple Installed ----------------------------------------------------------- 20
Figure 32: Reassembling Irrigation Valve ------------------------------------------------ 21
Figure 33: Reinstalling Valve Body Screws ----------------------------------------------- 21
Figure 34: Cutting Blow Gun Tube --------------------------------------------------------- 21
Figure 35: Assembled Receiver Adapter ------------------------------------------------- 22
Figure 36: Bonded Receiver Pipe ---------------------------------------------------------- 22
Figure 37: Attached Trigger Handle ------------------------------------------------------- 23
Figure 38: Air Chamber Threads ----------------------------------------------------------- 23
Figure 39: Air Chamber/Trigger Valve Assembly --------------------------------------- 23
Figure 40: Marking Receiver Pipe for Cutting ------------------------------------------- 24
Figure 41: Bonded Receiver Pipe ---------------------------------------------------------- 24
Figure 42: Attaching Zip Ties ---------------------------------------------------------------- 24
Figure 43: Completed Air Cannon --------------------------------------------------------- 25
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PurposeAir cannons are used to launch various projectiles in such a way which surpasses the
throwing range of an ordinary human being. You may have witnessed them in use at
sporting events where individuals on the field launch t-shirts, footballs or other
promotional items to fans in the nosebleed section of a stadium, or on a less powerful scale,
at carnivals where a participant would shoot foam or other soft balls at targets in order to
win a prize. Structural engineers use air cannons to launch two by fours at walls, doors and
windows to evaluate safety while developing tornado resistant building materials, while
still others use air cannons for pure recreational use and entertainment to launch potatoes,
pumpkins or other various produce items distances from 100 yards and up to nearly a mile.
The air cannon you will be building in this project will have a range of 50-200 yards,
depending on the size, shape and weight of the projectile and is also designed withversatility in mind due to the option for interchangeable barrel sizes in the future.
ScopeThis instructional document will direct you through the entire building process from
selecting proper materials to final assembly, testing and operation.
Intended UsersThe individual who will utilizing this instructional document will have a working
knowledge of the tools and their uses required for this project, but not necessarily have
experience when working with plumbing materials. The user will have safety as a top
priority at all times.
UsageThe instructions in this document are intended to be completed in sequence. Failure to
follow the sequence as set forth herein may cause unintended operation and potentially
imminent danger.
Safety Information
It is the users responsibility to research, observe and comply with all local, stateand federal laws and statutes which may govern, regulate of restrict the use or
possession air cannons.
Read and abide by ALL directions and safety precautions within this document.
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Safety Information (continued)
NEVER point the air cannon at any person whether or not the barrel is loaded or theair chamber pressurized. ALWAYS point the air cannon in a safe direction when
using or loading.
ALWAYS treat this unit with the same duty of care as if it were a firearm.
Do not place your hand or fingers on the firing mechanism unless the gun is pointedat the intended target.
ALWAYS launch the air cannon in a safe direction. This means NEVER point or fire atanything that you cannot clearly and identify easily as a target.
Air cannons can be dangerous and even deadly when improperly handled. Neverstore or transport a loaded air cannon. Do not load the air cannon unless you intend
to shoot it immediately.
NEVER attempt to pressurize the air chamber above 100 psi. The pressure safetyvalve it set to open if the pressure rises above 115 psi.
DO NOT attempt to circumvent the pressure safety valve. It is installed for yoursafety and protection.
DO NOT use or pressurize the air cannon if it is become broken, damaged or if youhave dropped it on a hard surface until a full inspection is performed on the
components and joints.
ALWAYS perform an inspection on the air cannon before and after use to check fordamage or leaks.
Always remember to discharge the air chamber pressure when not in use by gentlyopening the safety pop-off valve.
The user of this document assumes ALL liability and risk associated with ANYactions taken pursuant to the information contained herein.
This instructional document is for educational and instructional purposes only. The author of this instructional document is not responsible for the use or misuse of
the plans or any device created from the plans.
----------------------------------- IMPORTANT -----------------------------------
REVIEW ALL OF THE ABOVE SAFETY INFORMATION BEFORE BEGINNING THIS PROJECT
---------------------------------------------------------------------------------------------
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Read Entire Manual
It is IMPERATIVE that the user read and
understand the entire instructional guide before
starting any processed described herein.
Gather Tools and Materials
Gather all of the tools and materials necessary to
perform each step of every process as instructed
by this guide.
Assemble the Air Chamber
In this process you build the air chamber to the
air cannon, which will be filled with and hold the
pressurized air until released with the trigger
valve.
Assemble the Barrel
The barrel of the air cannon will consist of a 3
diameter barrel, 24 long with a threaded
connector which attached to the receiver.
Assemble the Trigger Valve
Trigger valve is an irrigation sprinkler valve
which will be modified for use in this application.The trigger valve effects a rapid release of air
pressure from the air chamber during operation.
Assemble the Receiver
The receiver is the pipe and adapters which
connect from the outlet of the trigger valve to the
inlet of the barrel.
Final Assembly
The final assembly is possible once all of theindividual components to the air cannon are
assembled.
Testing and Operation
After final assembly the air chamber will be
pressure tested and the trigger valve will be
tested for functionality. A brief on the operation
will also take place. Figure 1: Process Flow
START
Read
Gather Tools & Materials
Air Chamber
Barrel
Trigger Valve
Receiver
Final Assembly
Testing and Operation
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The tools required for this project are common and easy to find in hardware stores if not in
the garages an average hobbyist. The only tool which may be more difficult to find is the
Pipe Thread Tapping Tool, which may need to be sourced from a plumbing or specialty tool
supplier. Be absolutely certain about the type of PVC cement you purchase as further
described in the warning below.
Required Tools
PVC Primer (Purple or Clear)
PVC Cement (Heavy Duty) - SEE WARNING
Power Drill or Drill Press
15/32" Drill Bit
1/4" Pipe Thread Tapping (cutting) Tool
Adjustable (Crescent) Wrench
1 Roll Teflon Thread Seal Tape
Bench Vise or Other Stationary Clamping Device
#2 Phillips Screwdriver
Flat Head Screwdriver
Heavy Duty Box Tape (2-3" Piece)
J-B WELD Epoxy & Sealant
Popsicle Stick (For Mixing J-B WELD)
Hacksaw
Rasp (file)
Measuring Tape
Utility Knife
Permanent Marker4 10-12" Heavy-Duty Zip Ties (Or A Single 3' Tie)
Air Compressor
Safety Goggles or Glasses
DANGER: Do NOT substitute PVC
cement with multi-purpose
plumbing cement, which is labeled
for use on PVC, CPVC and ABSplastic materials. This type of
cement does not create as strong
of a bond as single-purpose PVC
cement. Doing so in this
application may cause joint leaks
or possible bursting or explosion
resulting in severe injury or death.
DANGER: ALWAYS remember to
wear safety glasses, goggles or
other appropriate eye protection
when working with tools and
when building, testing and
operating the air cannon
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The materials list for the air cannon is extensive, but nearly all of the plumbing parts can be
purchased at your local hardware or plumbing store. Gather all of the materials necessary
for each component prior to beginning building each phase of the air cannon.
Danger: ALL PVC used in this project should be Schedule 40 rated PVC, generally
indicated with a Sch. 40 marking on each part, as shown in the figures below.
Schedule 40 PVC is pressure rated (generally up to 200 psi) and able to withstand
the pressure which will be utilized in this application. Failure to use Schedule 40
PVC will cause a risk of bursting or explosion of the air cannon during use which
may result in severe injury or death.
Component Description Picture Source
Air Chamber4" Sch. 40 PVC Pipe - 16" in
LengthThe Home Depot
Air Chamber 4" Sch. 40 PVC Coupling The Home Depot
Air Chamber4" to 3" Sch. 40 PVC Reducer
BushingThe Home Depot
Figure 2: Sch. 40 Example 1 Figure 3: Sch. 40 Example 2
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Component Description Picture Source
Air Chamber3" to 2" Sch. 40 PVC Reducer
BushingThe Home Depot
Air Chamber2" to 1" Sch. 40 PVC Reducer
BushingThe Home Depot
Air Chamber1" Sch. 40 PVC Pipe - Approx
2" in LengthThe Home Depot
Air Chamber1" Sch. 40 PVC Female to Male
Threaded AdapterThe Home Depot
Air Chamber 1/4" Brass Hex Nipple The Home Depot
Air Chamber 1/4" Brass Pipe Tee The Home Depot
Air Chamber 1/4" Brass Schrader Valve
Locke (plumbing)
Supply
Air Chamber
Pressure Guage - 1/8" Male
Pipe Fitting (Capable of up to
120 psi)
NOSHOK, Inc.
www.noshok.com
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Component Description Picture Source
Air Chamber1/4" to 1/8" Brass Reducer
BushingThe Home Depot
Air Chamber 4" Sch. 40 PVC End Cap The Home Depot
Air Chamber1/4" 115 psi Safety Valve
(Pop-Off Valve)Lowe's
Barrel2" Female to 2" Male
Threaded AdapterThe Home Depot
Barrel 2" Pipe - 2.5" in Length The Home Depot
Barrel 3" to 2" Reducer Bushing The Home Depot
Barrel 3" Coupling The Home Depot
Barrel 3" Pipe - 24" in Length The Home Depot
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Component Description Picture Source
Trigger ValveIrrigation Sprinkler Valve
1" Female ThreadedThe Home Depot
Trigger Valve 1/4" Brass Hex Nipple The Home Depot
Trigger Valve Air Compressor Blow Gun The Home Depot
Receiver1" Female to Male Threaded
ElbowThe Home Depot
Receiver 1" Pipe - Approx 6" in Length The Home Depot
Receiver 1" Street Elbow The Home Depot
Receiver 2" to 1" Reducer Bushing The Home Depot
Receiver2" Female to 2" Female
Threaded AdapterThe Home Depot
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Before you begin assembling the air cannon, you must bear in mind how critical the strength
and integrity of each cemented PVC bond on the unit is to your own personal safety and the
safety of others around you. Review the information below describing Proper PVC Bonding
Technique BEFORE continuing.
Figure 6: PVC Bonding Directions
Step 1: Apply PVC primer to the
hub of the pipe fitting, spreading
with the applicator to coat the
entire surface to be bonded.
Step 2: Apply PVC primer to endof the pipe and let primer dry for
about 1 minute before applying
cement.
Step 3: When primer is dry, apply
clear PVC cement to the hub and
pipe end of the fitting spreading
to coat the entire primed surface.
Step 4: Without delay, push the
pipe into the hub of the fitting
WHILE turning the pipe about
one-quarter turn. This removes
any air bubbles which may have
formed in the cement. Hold for 1minute.
Step 5: Wipe off excess glue with
a cloth or towel.
Figure 5:
Heavy Duty PVC Cement
Figure 4: PVC Primer
Danger: Avoid contact
of PVC chemicals with
skin, eyes or any body
part. Avoid breathing ofvapors and use in well
ventilated area. Follow
all product label
directions, precautions
and warnings during
use.
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Assembling the Air ChamberThe strength and integrity of the air chamber is one of the most important factors to safety
and desired operation of the air cannon. The air chamber is constructed using 4 pipe and
will hold the air pressure until released by the trigger valve. Attached to the chamber will
be a cap on one end with the safety pressure valve, the pressure gage, the air inlet valve
(Schrader valve) and the reducer bushings so that the air chamber may be threaded onto
the trigger valve.
Warning: Make sure you have studied proper PVC bonding techniques as
previously discussed in this guide before proceeding.
1. Gather the listed materials required to
build the air chamber
2. Bond the 4 x 16 long pipe to the 4
coupling using the aforementioned
proper PVC bonding technique.
See Figure 7
3. Prepare a dry-fit of the reducing
bushings and threaded adapter to verify
compatibility prior to bonding.
These items include:
4 to 3 reducer bushing 3 to 2 reducer bushing 2 to 1 reducer bushing 1 pipe2 in length 1 female to 1 male threaded
adapter
See Figure 8
Caution: Be sure to NOT press the pieces so firmly together leaving them difficult to
separate by hand prior to permanent bonding.
Figure 7: Air Chamber (Step 2)
Figure 8: Air Chamber Bushings (Dry-Fit)
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4. Separate the dry-fit components from
the previous step and bond them
permanently with PVC primer and cement
using proper PVC bonding technique.
See Figure 9
5. Drill a 15/32 hole through the coupling
and pipe wall approximately 1 from the
inside edge of the coupling. Deburr and
clean the edges of the hole, if necessary.
See Figure 10
6. Using the 1/4 male pipe thread tapping
tool, carefully begin to hand-thread the
tool into the hole. Try to keep the tool as
perpendicular to the pipe as possible.
See Figure 11
7. Once the tapping tool becomes too
difficult to turn by hand, continue to
thread the tool into the hole using an
adjustable wrench and cut the threads
until approximately 1 of the tapping tool
has been inserted into the hole.
See Figure 12
Figure 9: Air Chamber Bushings (Bonded)
Figure 10: Drilling Air Chamber Inlet
Figure 11: Thread Cutting Tool
Figure 12: Cutting Air Chamber Threads
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8. Wrap one end of the 1/4" brass hex
nipple approximately 3-4 layers of Teflon
thread seal tape.
See Figure 13
9. Thread the nipple into the pipe and
tighten with the wrench until flush with
the surface.
See Figure 14
This brass nipple will connect to a pipe tee which will provide ports for the fill valve
(Schrader valve) and for the air pressure gage.
10. Prepare the 1/4 brass pipe tee, air
pressure gage, 1/4 to 1/8 brass reducer
bushing and brass Schrader valve forconnection by wrapping the threads with
3-4 layers of Teflon thread seal tape
similar to step 8 above.
See Figure 15
11. Connect the components in the
configuration shown in step 10 and
tighten them firmly with a wrench. The
bench vise will be very helpful in this step
by holding the brass tee in place while
tightening the connecting components.
See Figure 16
Figure 13: Applying Teflon Tape to Threads
Figure 14: Air Chamber Inlet Nipple
Figure 15: Pressure Gage and Schrader
Valve Configuration
Figure 16: Assembled Air Chamber Inlet
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12. Prepare the brass nipple on the air
chamber for connection with thread seal
tape and connect the assembled tee to the
chamber. Tighten firmly and position the
tee as shown in Figure 17.
13. Drill a 15/32 hole in the center of the 4
end cap.
See Figure 18
14. Using the same technique in steps 6-7, cut
pipe threads into the hole then remove alldebris created from the drilling and
thread cutting process.
15. Prepare the 1/4" brass safety pop-off
valve for connection by applying Teflon
thread seal tape, thread into the 4 end
cap and tighten firmly with a wrench.See Figure 19
You will now prepare the 4 end cap for connection to the air chamber. In performing steps
5-7, debris such as PVC shavings and curls has fallen into and collected in the air chamber.
Now is the time to clean all debris from inside the air chamber before sealing it with the
end cap because you will not have access to this area after step.
16. Bond the 4 end cap to the air chamber
using proper PVC bonding technique.
Figure 20 shows the completed air
chamber. Set aside until the air cannon
final assembly.
Figure 17: Installed Air Chamber Inlet
Figure 18: Drilling Air Chamber Cap
Figure 19: Safety Pressure Valve
Figure 20: Completed Air Chamber
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Assembling the BarrelThe barrel of the air cannon will hold the projectile prior to launching. Just like the air
chamber, the barrel must be capable of withstanding a significant amount of air pressure.
The difference between the barrel and the air chamber, however is that the barrel will be
subject to instantaneous pressure spikes when the air is released from the chamber,
therefore the integrity of the barrel connections is crucial to the safety of the individualusing the air cannon. The air chamber is constructed of 3 pipe which will be reduced to 2
pipe and connected to a 2 male threaded adapter which will attach to the air cannon via
the barrel receiver.
1. Prepare a dry-fit of the barrel coupling,
reducer bushings and threaded adapter to
verify compatibility prior to bonding.
These items include:
3 coupling 3 to 2 reducer bushing 2 pipe2.5 in length 2 female to 2 male threaded
adapter
2. Separate the dry-fit components from
the previous step and bond them togetherusing proper PVC bonding technique. The
assembled barrel connector is shown in
Figure 21.
3. Bond the 3 x 24 barrel to the barrel
connector coupling using proper PVC
cementing technique. Figure 22 shows the
completed barrel. Set the barrel aside
until the air cannon final assembly.
Figure 21: Threaded Barrel Connector
Figure 22: Completed Barrel
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Assembling the Trigger ValveThe trigger valve is a unique component in this model of air cannon due to the fact that it is
not a typical PVC or brass pipe fitting. The trigger valve is actually an electronically
actuated sprinkler valve used residential and commercial lawn irrigation systems which
will be modified for use in this application. The purpose for using this type of valve as a
trigger in the air cannon, as opposed to using a standard brass or PVC ball valve, is thatvalve can open and release the pressure from the air chamber much more rapidly, near
instantaneous, which can have a dramatic effect on the power and speed in which the
projectile is launched from the barrel.
The modification of the valve as described in the steps below removes the electronic
actuation motor and essentially turns it into a manually operated combo valve, whereby
opening the outer valve via the trigger handle effects the opening of the main pressure
release valve, thereby releasing the pressure from the air chamber and allowing rapid flow
into the receiver and barrel of the air cannon.
Caution: Pay attention to this process carefully because performing the steps
incorrectly may render the valve permanently inoperable.
1. The trigger comes from the box with the
electronic actuator motor attached. The
actuator is the black cylinder with two
wire leads attached.
See Figure 23
2. Remove the electronic actuator by
unscrewing it from the valve body.
Discard, if desired.
See Figure 24
Figure 23: Unmodified Irrigation Valve
Figure 24: Electronic Actuator Removed
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3. Using a screwdriver, remove 8 screws
from the circumference of the valve body
and set aside. These screws will be used
again when reassembling the valve.
See Figure 25
4. Separate the top half from the bottom half
of the valve body. You may need to use a
flat head screwdriver along the seam to
pry apart the pieces. Be careful not to cut
the rubber seal just inside the outer edge
of the seam. Set the base and spring aside.See Figure 26
5. Apply a small piece of heavy duty box
tape covering the small square-shaped
hole along the inside edge of the valve
body. This will prevent leakage of the
sealant into the inner valve.
See Figure 27
6. Prepare a mixture of equal parts
J-B WELD (steel + hardener) sealant to be
applied to the cavity where the electronic
actuator was located. Mix the twocomponents together thoroughly with a
popsicle stick on a thick piece of paper or
cardboard. You will need approximately
15cc, or a half-dollar size amount of
prepared sealant.
Figure 25: Removing Top Screws
Figure 26: Disassembled Irrigation Valve
Figure 27: Taping Valve Hole
Figure 28: J-B Weld
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Danger: Avoid contact of J-B WELD with skin, eyes or any other body part. Use in a
well ventilated area to avoid breathing of vapors. Follow all directions, safety
precautions and warnings included on the product packaging.
7. Transfer the prepared J-B WELD sealant
mixture with the popsicle stick to the
threaded cavity on top of the valve body
covering the air ports inside completely.
Transfer the entire mixture to the cavity.
Place the valve body on a flat, even
surface to cure and this process will allow
the J-B WELD to settle into a smooth, even
seal inside the hole as shown in Figure 29.
Caution: You must allow the sealant to cure 10-12 hours before proceeding.
8. Now that the sealant is fully cured,
remove the heavy duty tape which was
applied previously in step 5. Drill another
15/32 hole in the center of the valve
body and cut 1/4" pipe threads with the
thread cutting tool. Be sure to center thehole as closely as possible within the
circle.
See Figure 30
9. Prepare the other 1/4" brass nipple with
Teflon thread seal tape and thread into
the hole in the valve body as shown in
Figure 31. Tighten thoroughly with awrench. The trigger handle will attach to
this brass nipple which will allow the
valve to be opened manually.
Figure 29: Sealed Valve Cavity
Figure 30: Cutting Valve Body Threads
Figure 31: Valve Nipple Installed
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The modifications to the sprinkler valve are now complete and it is time to reassemble the
unit and prepare the trigger valve for assembly.
10. Re-attach the top of the valve body to the
base of the valve body while carefully
centering and aligning the internal spring
and the screw holes along the outerdiameter.
See Figure 32
11. Reinstall the screws which seal and hold
the valve together and thread the screws
in by hand until they are about halfway
inserted as shown in Figure 33.Tightenthe screws with a Phillips screwdriver
and set the unit aside until final assembly.
Caution: The valve body is made of softer plastic material. When tightening the
valve body screws with the screwdriver, be as careful as possible not to over-torquethe screws causing them to strip the threads of the valve body. This will cause the
valve to leak under pressure and result in undesired operation of the air cannon.
The air compressor blow gun which will connect to the irrigation valve consists of a plastic
body, plastic trigger, brass threaded receiver and a metal tube approximately 4-5 long. The
metal tube will not be need in this project and will need to be cut from the blow gun. The
blow gun will be attached to the modified irrigation valve during final assembly.
12. Using the bench vise to hold the blow gun
firmly, use a hack saw to cut the metal
tube off as close to the blow gun handle as
possible. Set aside until the air cannon
final assembly.
See Figure 34
Figure 32: Reassembling Irrigation Valve
Figure 33: Reinstalling Valve Body Screws
Figure 34: Cutting Blow Gun Tube
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Assembling the ReceiverThe receiver of the air cannon consists of the pipe and adapters which connect the trigger
valve to the barrel. The receiving end which attaches to the barrel has a 2 threaded female
adapter which would allow multiple sizes and types of barrels should you wish to build
them.
1. Prepare a dry-fit of the receiving
adapter components to verify
compatibility prior to bonding. These
items include:
2 female pipe to 2 femalethreaded adapter
2 to 1 reducer bushing 1 street elbow
2. Separate the dry-fit components from
the previous step and bond them together
using proper PVC bonding technique. The
assembled receiving adapter is shown in
Figure 35.
The second part of the receiver is the 1 male threaded elbow and the 1 PVC connecting
pipe. The second part will not be bonded to the receiving adapter above until the final
assembly process.
3. Bond the 1 x 6 PVC pipe to the 1 male
threaded elbow as shown in Figure 36. Be
sure to remember proper PVC bonding
technique.
Figure 35: Assembled Receiver Adapter
Figure 36: Bonded Receiver Pipe
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Final AssemblyNow that all of the individual components of the air cannon are assembled and all adhesive
is fully cured, it is time to assemble the components into one unit. You may want to refer to
the picture of the fully assembled air cannon on the cover page for reference.
Caution: The trigger valve is directional and air flows only one way through the 1
female threaded ends of the trigger valve, or the inlet and outlet. The body of the
valve will have arrows ( ) indicating the flow direction of the valve.
Steps 1, 2 and 4 below involve connecting components to the trigger valve and
ensuring these connections are made on the appropriate side of the valve is critical.
1. Wrap the 1/4" brass nipple on the trigger
valve with 3-4 layers of Teflon thread seal
tape and attach the air compressor blow
gun. Turn the handle until almost
completely tight and then point the
trigger lever towards the inletend of the
valve body.
See Figure 37
2. Wrap the threads on the 1 male threaded
adapter located on the end of the air
chamber with 3-4 layers of Teflon thread
seal tape and attach to the trigger valve
on the inletside. Turn until the valve is
firmly attached and continue turning until
air pressure gage is at the 10 oclock
position and the valve handle is in the 6
oclock position.
See Figures 38 and 39
Figure 37: Attached Trigger Handle
Figure 38: Air Chamber Threads
Figure 39: Air Chamber/Trigger Valve
Assembly
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3. Insert the 2 male threaded barrel connector into the 2 female threaded receiving
adapter and turn until hand tight. Do not over-tighten and do not apply Teflon
thread seal tape when connecting these components.
4. Wrap the 1 threads on the male threaded elbow from the lower half of the receiver
with 3-4 layers of Teflon thread seal tape and insert into the outletend of the
trigger valve. Continue turning until the connection is tight and the 1 pipe is in the12 oclock position in comparison to the pressure gage and trigger handle.
5. Lay the barrel and other components side
by side where the barrel touches the air
chamber and make a cutting line with a
marker on the 1 receiver pipe to allow
enough material to be bonded into the
receiving adapter.
See Figure 40
6. Remove the 1 receiver pipe from the trigger valve and make a cut with a hacksaw
at the cutting line. The bench vise may come in handy one more time to hold the
pipe steady while making the cut. File the cutting debris left on the edge of the pipe
with the rasp. Re-attach the receiver to the trigger valve in preparation for the next
step.
7. Using proper PVC bonding technique,bond the receiving pipe to the receiving
adapter with the barrel attached as
shown in Figure 41. This is a one-time
shot at aligning the barrel and air
chamber correctly. As soon as you press
the pieces together with the cement
applied rotate the barrel to come into
alignment with the air chamber.
8. In order to hold the air chamber and
barrel securely, attach a series of zip ties
around the air chamber and barrel along
the inside edge of the air chamber end cap
as shown in Figure 42.
Figure 40: Marking Receiver Pipe for
Cutting
Figure 41: Bonded Receiver Pipe
Figure 42: Attaching Zip Ties
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Air Chamber Pressure TestThe pressure test of the air chamber is the first in a series of steps which will test the
functionality of the air cannon. Make sure you wear safety goggles!
1. Begin this test by pressurizing the air chamber with an air compressor to 20 psi andwait 3-5 minutes. Observe the pressure gage and note if the chamber holds thepressure for the entire period. Slightpressure drops (0-5 psi) are normal the first
few times the chamber is pressurized. Release the pressure by manually opening the
pressure safety valve.
2. Repeat the process in Step 1 at 40 psi, 80 psi and finally at the maximum 100 psi.3. If pressure leaks are found, determine the source of the leak and take the
appropriate steps necessary to remedy the leak. This may be as simply as applying
more Teflon thread seal tape to leaking joints.
Trigger Valve Test
1. Pressurize the air chamber to 40 psi and, while pointing the air cannon in a safedirection, release the pressure using the trigger valve.
NOTE: Squeeze the trigger valve quickly and completely. (Squeezing the
trigger valve slowly does not work well)
Figure 43: Completed Air Cannon
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2. Repeat the process in Step 1 at 60 psi, 80 psi, and 100 psi. Be prepared because the
air cannon will become increasingly LOUD as the pressures increases.
Operation
----------------------------------- IMPORTANT -----------------------------------
REVIEW ALL SAFETY INFORMATION ON PAGES 5-6 OF THIS DOCUMENT PRIOR TO USE
PERFORM ALL OPERATIONAL TESTS DESCRIBED ABOVE PRIOR TO USE
-------------------------------------------------------------------------------------------
During the testing process, you should now be familiar with the general functionality and
mechanism of the air cannon and you are ready to start launching projectiles, but first you
must understand how to load the barrel.
In order for the air pressure released from the air chamber to have the greatest effect on
desired projectile, the projectile must seal as tightly as possible in the barrel. If there is any
airspace between the walls of the barrel and the projectile, the majority of the air pressure
will simply bypass the projectile and will not propel the projectile with any substantial
force. Choose a projectile that can be slightly compressed when loaded into the barrel to
achieve the most effective seal. For smaller projectiles, change to a smaller barrel, which
will be discussed below.
For the purposes of this document, the air cannon will be used for launching t-shirts as
discussed in the introduction.
Launching A T-Shirt1. Fold the t-shirt lengthwise 2-3 times and then tightly roll the shirt into cylindrical
shape, ensuring the rolled shirt will be slightly larger than the internal diameter of
the barrel.
2. Wrap the shirt with 2-3 strips of heavy duty box tape to maintain shape.
3. Insert the shirt into the barrel while slightly compressing the shirt to create a good
seal.
4. Push the shirt down to the base of the barrel.
5. Pressurize the air chamber. 50 psi is the initial recommended air pressure until you
become more comfortable with the air cannon.
6. CAREFULLY pick up the air cannon WITHOUT placing you hand on the trigger
handle.
7. Aim at the intended target and firmly squeeze the trigger handle to launch.
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Future Options
The air cannon built in this instructional document was engineered with the capability to
have interchangeable barrels in order to launch a variety of sizes and types of different
projectiles. A 2 diameter barrel is the optimum size for launching potatoesand a 2.5 size
is the optimum size for launching slightly larger projectiles such as tennis balls. Smaller
diameter barrels such as 1 to 1.5 also have their uses and size of the barrel is determined
by the size of the desired projectile.
By building this air cannon you have now gained enough knowledge and experience to
select appropriate materials and build different barrel sizes. Whatever size (diameter)
barrel you choose, simply install a bushing to increase the size to 2 and attach a 2 male
threaded adapter. Then you can simply detach the 3 barrel, attach the new barrel and
operate as normal.
Have fun and ALWAYS remember to practice safe launching.