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I'm trying to find a simple yet effective way to trigger my 1" ball valve that pilots the piston in my new cannon. I'm familiar with the pneumatic ram idea that was used in that colorful dual tank cannon a while ago. Very nice idea but not the way that I want to go. My other cannon uses a Rainbird cp-100 and works great, but I just wanted to see if I could build a cannon with no special order/hard to get components. (sprinkler valves are almost impossible to get retail for me as I live in an area with a brand new Home Depot and Lowes with useless employees). Does anyone have any ideas on how to open the ball valve quickly? (and hopefully without breaking it off of the cannon )

yes, like you said, a pneumatic ram is the way to go.

The ram is cool, very good concept but I don't want to go to the trouble of the second tank and fittings etc. There has to be a good mechanical way of "smacking" the valvel open quickly. I was toying with the idea of a crossbow concept except with that slingshot tubing instead of the bow part. I would use it to slide a heavy rod down another guide rod and use the accumulated inertia colliding with the valve's handle to open it quickly. Does anyone have any ideas along the lines of stored mechanical energy? Its important to keep in mind also that my ball valve is a pilot for my 3" piston, not the means of sending air out my barrel. That makes this a bit different than the scenario calling for the air ram on the other cannon. That was their primary air supply valve , not a pilot valve.

You can put a fat spring in the handle so when you pull out a nail it actuates like <a href="http://www.spudfiles.com/forums/viewtop ... &">this</a> uses.

sprinkler valves are almost impossible to get retail for me as I live in an area with a brand new Home Depot and Lowes with useless employees

You can't find sprinkler valves at Home Depot or Lowe's by yourself?

If he lives up north those parts are seasonal. As soon as labor day weekend is over, Home Depot and Lowes takes out their stock of sprinklers. You'd have to order online or go south where they don't get snow to buy them this season. The plumbing supervisor at my Home Depot told me that a local plumbing supply store may have some stocked all year round. He admitted it was kind of stupid, but they're forced to send their old stock to warehouse.

<a href="http://img.photobucket.com/albums/v611/ ... BV.png">An idea I had a while ago</a>.

The hole leads to the chamber.
The red dots are O-rings.

Pres the red switch, air goes in frot of piston, pushes it bacwards (uncovering hole)... BLAM, air comes through hole and forces the piston back big-time.

(alternativly, one could pull the piston back manualy. With, like, a string or something)

I think i got the idea. So the trigger lets air in, the piston schoots back, pulling the ball valve open, so pressure is released in the barrel.

Ok, got that, but what hole is connected to the chamber ? Is that the hole you drew next to the piston ?

Yes, "the hole" is the part in the drawing that is labeled "hole"...

Huh, thats a pretty cool setup noname. I'm thinking exactly like you:simple components and DIY. My project is about 4' of 4" for my chamber and a coaxial setup with 2" dia. barrel. Its pretty much like my last project [www.spudfiles.com/forum/dowload.php?id=2418&] except it has no ball valve instead of solenoid, no aluminum frame and shorter barrel. Much much more chamber too

Hm, i dont understand why the hole makes a connection between the piston pipe and the chamber . What is the meaning of that ? Teh chamber will depressurise trough the hole at the stopper ....

The hole leads to the trigger, which is probably a blowgun, or small ball valve.

http://www.sentex.net/~mwandel/cannon/air_gun.html

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