This is a instructable for my coaxial golfball gun, or any coaxial spudgun. If you're wondering, a coaxial is where the barrel is inside the chamber, much like a piece of coax cable for your TV.
Step 1: Safety
All spudguns and launchers are dangerous, and should be used in a safe manner in accordance with your local laws and regulations. Using them in a unsafe manner may lead to injuries or even fatalites you have been warned.
Step 2: The operating principles
A coaxial spud gun consists of a barrel with the pressure chamber surrounding it. Like a piece of coaxial television cable, The valve for a coaxial is either a diaphragm or piston(this project uses a piston)The piston seals up against the edge of the barrel that is contained in the chamber section when air is compressed is behind it. Channels or holes in the edge of the valve allow the air to pressurize the section of the chamber infront of the valve. When fired the air pressure behind the valve is vented through another valve, the piston is then forced back by the greater air pressure infront as the air pressure to the rear decreases, unsealing the barrel allowing the air to flow down the barrel firing the payload.
Step 3: The parts
You can get all the parts for just about $45-50usd
All fitting and pipe are schedule 40 unless stated.
2x4" adapter 4.50
4" cleanout and cap 4.00
4'feet 4" pipe hardwall pipe 6.75 (foamcore this is NOT pressure rated)
4' section 2inch schedule 80 pipe donated (est $15)
4' section 1 1/2 inch SRD-21(class 200 pipe) donated (est $2.50)
(you can't get is pipe at home depot/lowes, try a plumbing supply store Near pittsburgh try PipeCo in leetstale,PA)
2x pipe test caps 0.50 each
a section of scrap 3" pvc
a mouse pad
(already had all parts below)
Shrader(tire) valve 1/4NPT (est $3.50)
Pressure gauge 1/4NPT (est $4.00)
Ball valve 1/4NPT (est $4.00)
Four way coupler 1/4NPT (est $3.75)
1/4NPT thread tap (est $5.00)
PVC Primer (est $3.00)
PVC Cement (est $4.00)
15minute epoxy (est $5.00