The piston in the valve won't open when you drop the pressure behind it with the pilot valve. I turned the piston on a lathe put O-rings on it and it fits and moves really slick. You can blow on it and it seals and you can put vacuum on it and it moves back like it's suppose to, but when you put it ...

Hey Guys, A word of caution. I don't want anything like this to happen to any of you. My pvc cannon exploded this afternoon. I was trying to see how much damage the cannon would do and it blew up. The cannon was shooting through 2 sheets of 1/4" luan plywood and a piece of 3/4" particle board. I kep...

I finally finished my cannon . Here are some finished pictures. I built a base so you can move the cannon horizontal and vertical. I added sights and two grips with a trigger on the right side. I also cut a muzzle brake in the barrel. Everything seems to work OK. Many thanks to all of you for your e...

The easiest way I've found to remove the stop collars from bushings and couplings is with a router with a flush trim, or a pattern bit. If you have a router table it makes it even easier. Thought this might help someone.

Here are some pictures of the piston. It's 1 1/2" pvc. I used a router table and a v-groove bit to cut the oring grooves. The piston is hollow. I thought the lighter the better. A 1 1/4" cap fits inside the piston almost perfect. I glued it in the back and filled the voids with hot melt glue then gl...

This is my first attempt to build an air piston cannon. It has two 3"x 24" air chambers and a 1 1/2" x 32" barrel. I made the barrel removable to accommodate different sizes. The air chamber is also removable. The air valve is made from a 2" PVC tee with a 1 1/2" x 3 1/2" piston made from 1 ½” PVC p...