Piston valve mini cannon

[Jose Arcadio Buendia]

This is my second piston valve mini. The first I dismantled it because it didn't have enough chamber volume. I use a carbonated drink bottle for this one to have more volume and very light weight. I had a combustion mini, but this cannon even a 40 psi beats it. I was quite surprised about the power it has the first time I shot it. I made a design with PVC fittings so that I could open the back to be able to service the piston. I plan on taking it at maybe 80 to 100 psi.

Barrel: Bic Round Stic pen tube ( length: 6.75", ID: .25")
Chamber: Sch. 40 PVC pipe (1/2" and 3/4") and a 8 oz. (237 mL) carbonated malt drink bottle.


Here is the piston. It is molded hot glue with tire tube as seal. I put that spring behind the piston to cushion the backward movement.


I modified a threaded 3/4" male coupling to put a schrader valve with epoxy.


This is the cannon with a 2 pen barrel extension and tape around the bottle to prevent scratching and to reinforce it.


This was a wooden skewer against cardboard at 40 psi with the barrel extension.

Here is a video of a wet paper ball against a soda bottle at 40 psi:
[youtube][/youtube]

[jackssmirkingrevenge]

I modified a threaded 3/4" male coupling to put a schrader valve with epoxy.

That made me almost tear up with nostalgia

Nice effort, I'm guessing your piston has too much movement if that spring can fit behind it though.

[Jose Arcadio Buendia]

Thanks for the advise. I changed the spring for this piece of hose to limit the movement.