SpudFiles

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]

Jose Arcadio Buendia wrote: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.

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