SpudFiles

I need ideas on how to make a simple and cheap valve that requires no machining or anything difficult. Something that can be made in large quantities. It would hold about 10 PSI - 20 PSI and fire foam pellets. It is to be used with half inch pipe.
Diagrams would be helpful.

So the barrel is 1/2"

You can use a 1" Tee and a 1/2" elbow and a 1" to 1/2" bushing...

<img src="http://img57.imageshack.us/img57/9058/b ... tee6cz.png">

It's easy to make other than the diaphragm, someone else can help with that

How would the elbow get inside the tee? Unless its like a microscopic elbow, I just don't see that happening... this is half inch we are talking about here...

<img src="http://img363.imageshack.us/img363/2669/teefits9zl.png">

I checked thoose myself at Lowes with standart NSF-PW parts....

It's a decsending order, so 1/2" should fit in 1" Tee, if not it does fit in 1-1/4"

You just put the Elbow so both the ends are pointing up and put them in the Tee while the top outlet\inlet of the Tee is pointing up....

You have to glue a pipe into the Elbow while it's inside of the Tee, and bore out the stop in the bushing and glue that onto the pipe that's in the elbow and onto the Tee, make sure the elbow is in the center of the Tee and pointing straight up, it's actually really easy to do...

Ohh impressivly helpful.

Thanks, so how is the diaphragm made?

I came up with this yesterday. Its a manually operated barrel sealing valve. Its still a bit on the complicated side though. Any thoughts?

I like that idea,
but you would need to use like 20 psi or if you want to go higher, then
you need a stronger spring.

Is the small pipe the barrel or the chamber? It might not work as a chamber.

Benny, like the original post said, i will probably be using it at 20 PSI.

Spudstuff. The smaller pipe is the barrel. The chamber is not shown in the rendering.

I like that design. Will there be pressure behind the piston too? Because if there is it's going to be a challenge making the sliding part not leak but still slide.

I made a pneumatic gun with a modded sprinkler valve and it doesn't hold any air... when I pump it up it just makes an airhorn sound.
Can anyone tell me what is wrong with it?

Your valve isn'ts sealing when your filling it... Take off you lid and clean the inside of the sprinkler to get out PVC shaving and dust, and then use lithium soap\grease to lube the white and black parts, just a little layer of it to help it seal....

DJT you don't make sense, a sliding part that doesn't leak would be hard to make? It's just a coaxial piston without a pilot valve and instead a strong spring and the pistons pulled back by hand...

It'll be easy to make leakproof, just mold a piston out of hot glue and stick O-rings on it...

It looks like you pull the piston away from the barrel by hand with that bar with a circle on it. I said it would be hard to seal the bar that slides if the part behind the piston holds pressure. Now that I look at it I dont think it does though.

You want a nerf gun right,so heres a link from nerf haven and they also have a semi auto valve. http://nerfhaven.com/homemade/zero_basicvalve/