Spud Gun Air Control Assm

Free Web Hosting Provider - Web Hosting - E-commerce - High Speed Internet - Free Web Page

Here is a picture of the business end of my Air Cannon.
The purpose of the Piston-bumper is to keep the piston assembly from slamming into the clean out cap and breaking the cap or maybe even blowing it clean off! I made mine out of a piece of 1/4" ID. vacuum hose with a smaller piece of vacuum hose stuck in both ends to keep it together. You could cut a disk of the correct size out of some soft material of some kind, I used the hose because it was handy. DO NOT glue this in place in case you have to remove the piston for some reason. (ex. cleaning, fix air leak,something stuck in barrel)

See the Piston-Stopper-Assm picture for details about construction of the piston.

The spring was a leftover from the solenoid off a chevy starter I once replace and kept the spring.( I thought it might come in handy some day!) I had to stretch it to give it the right length I needed.

Note that a strong spring is not needed here because the piston assembly moves very freely.

The Sprinkler solenoid Valve is attached to the clean out cap with the shortest 1" pipe nipple I could find (about 1 1/2" long). I drilled a hole in the center of the cap the correct size to tap a 1" NPT hole. (actually I did not have the correct drill needed so I used the largest I had and the used a large reamer on the plastic to get it close to the correct size, then I easily used the tap to make the threads.)

I then did a trial fit of the pipe nipple and valve to find where I needed to put the Air Gauge/Air Fill Assembly. I removed the valve and pipe, then drilled and taped the 1/8" NPT hole. (see the Clean out Cap Drilling Picture)

The actual assembly was a bit of a trick to figure out just how to screw all the parts into the cap. I don't remember just how I did it but I think I placed the 1/8npt hole over to the side just enough so that when the small brass tubing parts where installed I could still screw on the valve. Just be sure to "think ahead" before drilling the small hole in this part of making the gun.

On my gun the end of the barrel sits 3" inside the end of the large pipe used as the air chamber.

NOTE that this is 3" from the end of the pipe NOT the attached clean out. I came up with the 3" from the design of my first piston assembly (which started to bind shortly after construction do to the large pipe slowly becoming "out of round") Also it is good to know that the piston assm. can be installed AFTER the clean out is attached. (this is good, do to the fact that I had to redesign the piston assembly.)

Safety Note:
Not shown on the valve is a manual pressure relief lever.
I used this to test my gun before I had made the handles or added the electronics (wiring and switches) to check for air leaks.
Once I had the bugs worked out I use electrical tape to keep this in place and from firing the gun unexpectedly (very dangerous!)
Never Forget:
SAFETY FIRST !!

The Air psi. gauge was removed from a portable air tank that I installed on a truck and changed to a liquid-filled gauge. This one is a 0 to 160 psi non-liquid-filled type.(read not expensive)

More Details