My first piston cannon

[pharmboy]

I finally finished it up today. Specs are as follows

valve - 2" Tee w/ 1.25" porting, piloted by 3/4" sprinkler valve, pneumatically actuated.
Chamber - 4" x 2' Cam-lock coupling for changing chambers.
Barrel 1.5" x 5' - screw-mounted for barrel swaps.
Extras - Shoulder stock w/ cheekpiece, Regulated CO2 setup.

Side view of the cannon


Long side view - I had to reconfigure my stock to fit my diminutive 6' frame.


Piston - made of 1.25" pipe/couplers w/ 2" steel fender washer and 2.25" neoprene washer


Piston bumper - rolled up strips of an old mousepad, notched to allow air through from the quick connecter.


Comments or complaints are welcome.

[Gaderelguitarist]

Looks very nice! Very clean construction. Congrats!

Now it just needs a fresh coat of paint and a couple damage pics.

[Gippeto]

Seconded!

Good work! The cheek piece is a nice touch.

Are there sights of some sort in the near future?

If possible, I would shorten the pilot hose, if not, then don't worry about it.

[trigun]

Nice gun I also like the included cheek rest but don't let the recoil knock your teeth out brushteeth . Only real improvements I can see are adding a possible barrel support, smaller hose but comfort over this because pilot volume barely effects performance, and lastly cam-locks for easy barrel swap.

Is that a palmer Co2 regulator ?

[pharmboy]

Nope, the CO2 regulator/hose is from Harbor Freight...$39.99...it's talked about in this post -

http://www.spudfiles.com/forums/co2-reg ... 17451.html

[mark.f]

Very nice cannon. I would work on the barrel support first and foremost. If you decide to shoot anything marginally heavy it will put a lot of stress on the elbow at the back.

[trigun]

Pharmboy thats funny because that my own topic haha. But you dont have any problems with it do you like going past 150 psi seems to be a big deal.

[pharmboy]

Well, after my trials/tribulations with getting my CO2 setup to work, I've assembled/pressurized it. It holds pressure, and the valve will actuate properly as long as there's more than 10 PSI applied to the inlet. Firing is quite smooth, giving a satisfying *Thwack* as the piston slams rearward. This coming weekend, I plan on getting my tank refilled and getting some good shots off...outside my hotel room.

[jon_89]

can you explain the piston a little more? looks good.

[pharmboy]

Well, playing around at the home improvement store, I notice that a 1 1/4" PVC union will fit darn well into a 2" pipe. So, the piston is 1 1/4" union w/ a 1 1/4" plug in one side, and a short length of 1 1/4" pipe in the other followed by a 1 1/4" cap over the end. I cut the pipe to a length to allow for an O-Ring groove of sorts. Being short of O-rings, I used a couple elastic hair bands (I keep them around for bundling cables in my laptop case), that I lubed w/ vaseline to slide easier in the 2" pipe. I drilled a 1/2" hole in the 1 1/4" plug, then ran a 1/2" bolt through the neoprene washer, through a 2" fender washer, and then secured it to the piston assembly.

Overall, it's very sturdy, not too terribly heavy, and I managed to assemble it with just a hacksaw and a wrench. Not terribly sophisticated, but I am working in a hotel room as you can tell from the pictures.

[jon_89]

so it fits in 2 inch pipe not the 2 inch tee?

[pharmboy]

so it fits in 2 inch pipe not the 2 inch tee?

Correct, the piston slides in a 2" pipe stub in the back of the 2" tee. Seems a little convoluted, but the picture below explains the layout quite well. Oh, just swap the locations for "Barrel" and "Chamber" as I switched the design from a chamber-sealer to a barrel-sealer.

[jon_89]

well tommorow i will give it ago.