High Pressure dump valves for piston operation

[Jolly Roger]

I've got a question regarding valves. I was looking at snipermans rifle and found that it's relatively similar to my design I'm still experimenting with. My setup is pretty much the same but I need a valve that can handle a relatively high pressure (300-440psi working pressure, and no it isn't made from pvc...) The trouble is finding one though. I've thought about just attaching a blowgun of some sort. That ghetto dude hooked his up to a hpa tank which is crazy but if it hasn't killed him yet I'm pretty sure it would be able to handle between 300 and 400psi...? Dunno. Heres some links to some of the valves I found. 1. http://www.bhdustcollectors.com/diaphragmvalvesbase.htm These are jet valves - used in dust collectors... ?I think they are exactly the same as a sprinkler valve by the looks and characteristics but I can't tell. The tech specs are so confusing... PCguy uses the same brand of valve on his launcher but I don't know if they work the same. 2. http://www.pvl.co.uk/valves.htm The second is a pilot operated piston valve (down the page) that can go up to 15bar. That'd be perfect except I was wondering if I could take the solenoid off and connect a pneumatic trigger just like a normal sprinkler valve. Wires and batteries are a pain in the ass. Anyone have any suggestions?

[Velocity]

I used the 1.5" Goyen valves on one of my <a href="http://forums.spudtech.com/topic.asp?TO ... unchers</a>, and it is only intended to pressures up to 125 PSI; However (unlike a sprinkler valve), this valve is made of aluminum, so when something breaks, it will definitely be the diaphragm.

[Brian the brain]

I say build your own out of galvanised fittings and a ballvalve as a pilot.
Performance is great, and it can handle high pressures.
Make the piston out of a bolt, metal washers and nuts.Then some neoprene for the sealing surface.

[Jolly Roger]

Yeah I was gooing for the realistic firing look, thought about ballvalves but their not really compatible with a rifle style gun. Fire extinguisher valves seem okay. They say that they can handle working pressures of over 290psi which would obviously have a very high burst pressure. I think I might build my own fittings and such as brian suggested. Yeah, now I come to it, I might just use that, KISS, unless of course anyone has any creative suggestions. Always open to ideas.

EDIT: I've dramatically changed my desgin and need a rethink on my valves. I've just stumbled accross some paintball 3 way push button valves... https://palmer-pursuit.com/ecom/product ... e798fc3a91 They are high pressure but I need them to work a certain way. I need the valve to instantly swith the air flow from (a to b) to (b to c)... If you follow. Going from a into b and then on the push of a button from b into c. I've attached a diagram to explain. Can anyone tell me if Im able to do this with these valves? I'm really stuck... (oh and by the way point b is the exhaust end of a piston cannon if that may aid in analysis.)

[dinsdale]

for your piston you could still use pvc rod, it would be lighter that steel, therefore faster, a solid pvc piston inside the pressurized metal tube will hold up