My slightly ergonomic Co-axial piston cannon!
Posted: Sat Sep 13, 2008 12:30 pm
This is my newest cannon. It's not the cleanest thing in the world, but I only had to buy 2 fittings for it, everything else i had laying around somewhere.
Main Body:
The main body is 1 1/4" Sch. 40 PVC. The Barrel is 1/2" sch. 40. I used a sch. 40 reducer with a bit of the middle sanded out to hold the barrel. The piston is a cap from this old medicine i used to need. It's arranged to where it encloses the barrel. As in the piston is backwards so to speak. I used a soft, closed cell foam tape on the back of the piston as a bumper.
The piston
The sealing face is on the barrel in this design. I found a flat rubber washer, used for like hose valves and stuff, that fit perfectly on the breech of the barrel. So it's glued onto the barrel. The piston is fully serviceable; all you need to do is unscrew 2 screws and pull off the reducer in the back.
Pilot/fill setup:
The fill valve is just a simple, 3/8th's NPT schrader valve threaded into the PVC where there are 2 layers, on the coupling. I use an air compressor or a bike pump to fill it. The pilot valve setup is a 1 1/4" to 3/4" threaded reducer, a 3/4" threaded nipple, and a 3/4" ball valve attached to it. The valve is really nice. It opens easily, even with just one finger. I added a 90 degree elbow and a bit of pipe to the back to direct the pilot air downward, and act as a pistol grip. So yay for ergonomics.
I usually fill it to around 60 psi. It shoots nerf darts like a nerf gun from hell. I couldn't even see the dart that i fired at a distance until it dropped about 200 feet away.
When I find some marbles that fit, or get around to making ice slugs, i will post damage pics and videos. But for now, enjoy!
Main Body:
The main body is 1 1/4" Sch. 40 PVC. The Barrel is 1/2" sch. 40. I used a sch. 40 reducer with a bit of the middle sanded out to hold the barrel. The piston is a cap from this old medicine i used to need. It's arranged to where it encloses the barrel. As in the piston is backwards so to speak. I used a soft, closed cell foam tape on the back of the piston as a bumper.
The piston
The sealing face is on the barrel in this design. I found a flat rubber washer, used for like hose valves and stuff, that fit perfectly on the breech of the barrel. So it's glued onto the barrel. The piston is fully serviceable; all you need to do is unscrew 2 screws and pull off the reducer in the back.
Pilot/fill setup:
The fill valve is just a simple, 3/8th's NPT schrader valve threaded into the PVC where there are 2 layers, on the coupling. I use an air compressor or a bike pump to fill it. The pilot valve setup is a 1 1/4" to 3/4" threaded reducer, a 3/4" threaded nipple, and a 3/4" ball valve attached to it. The valve is really nice. It opens easily, even with just one finger. I added a 90 degree elbow and a bit of pipe to the back to direct the pilot air downward, and act as a pistol grip. So yay for ergonomics.
I usually fill it to around 60 psi. It shoots nerf darts like a nerf gun from hell. I couldn't even see the dart that i fired at a distance until it dropped about 200 feet away.
When I find some marbles that fit, or get around to making ice slugs, i will post damage pics and videos. But for now, enjoy!