SpudFiles

i there,
im new on this forum, and id like to make a pneumatic canon like that one : http://www.duke.edu/~jwc13/tennisball.html

"How does the valve work? - To understand this you need a basic understanding of diaphragm valves, wikipedia has a detailed explanation of this although they call it a "solenoid valve." Technically it is a diaphragm valve actuated by a solenoid pilot valve. In my operation, however, I removed the solenoid valve and ran tubing to a remote, push button bleed valve to empty out the air from above the diaphragm."

but i dont understand how to mod this sprinkler.
i need your help buddies XD

At the top of this webpage there is a Wiki butten. Go to the "Spud Wiki" and do a search on "Modding a Sprinkler Valve".

Welcome to Spudfiles.

Im going to tell you before someone else does.

There are plenty of posts describing how to do so. Many, many, MANY posts.

Just look around.

In my opinion this particular cannon may be a bit much for you to build for your first one.

The guy also used a 2" sprinkler valve, which are expensive. Unless you want to fork out atleast $50 for the valve alone i'd build it on a smaller scale with a 1" valve that will only cost about $10-$15 if you live in America.

Not trying to show off my cannon or anything but something like these two cannons are good for your first:
http://www.spudfiles.com/forums/viewtop ... tml#123690
http://www.spudfiles.com/forums/viewtop ... tml#136108

Looks like Mr. Cornwell (http://www.duke.edu/~jwc13/tennisball.html) used a DWV "Y" in his design. It also looks like there is insufficient bracing between the barrel and chamber, particularly given the very long lever arm between the two. Probably OK for low mass ammo like a tennis ball, but put something heavier in it, and/or boost the pressure, and it may rupture at the elbows or the Y.