Pneumatic Gate Valve

You're likely to have problems with a gate valve and a granular product. "Pinch valves" are commonly used for this type of service. An example here:
Ned Simmons

Hi Jason,
Typically gate valves are used in fluids, whether it be air or an actual liquid. What diameter is the valve you are looking at?
Oliver

Oh, that's cool! Why didn't I think of that? You have any idea of what they sell for? Bob

--Woo hoo! It's a punkin gun waiting to happen! :-)

I am continually amazed at the breadth of knowledge displayed on this group. I was just reading the original post imagining the powdered candy running through some type of a hose with a way to pinch it off, and here Ned gives us a link to the exact part!
Vaughn

For what it is worth, Milnor commercial washing machines had a drain valve that may work for you, at least the idea. They used a piece of thin tubing much like inner tube, that was pinched of by a solenoid. The solenoid was connected to a couple of flat bars on either side of the tube. To stop the flow the two bars squeezed togather, pinching the tube closed. Greg

The tubes opening is 1/2".
"V8TR4" > candy product to fill plastic tubes. I want to make an automatic valve

I would try GlobalSpec They have learn more pages on all types of valves and other components Very deep technical content for users to view and its free

What does that mean?

You dont know what a pumpkin gun is?
Google is your friend.
Lots of fun!
Gunner
"This device is provided without warranty of any kind as to reliability, accuracy, existence or otherwise or fitness for any particular purpose and Bioalchemic Products specifically does not warrant, guarantee, imply or make any representations as to its merchantability for any particular purpose and furthermore shall have no liability for or responsibility to you or any other person, entity or deity with respect to any loss or damage whatsoever caused by this device or object or by any attempts to destroy it by hammering it against a wall or dropping it into a deep well or any other means whatsoever and moreover asserts that you indicate your acceptance of this agreement or any other agreement that may he substituted at any time by coming within five miles of the product or observing it through large telescopes or by any other means because you are such an easily cowed moron who will happily accept arrogant and unilateral conditions on a piece of highly priced garbage that you would not dream of accepting on a bag of dog biscuits and is used solely at your own risk.'

: What does that mean? --It's the hardest part to obtain and the most critical bit of tech needed to build a successful gun. Heh.

I have a 2" butterfly valve, air-operated with a 120V solenoid pilot that I've been saving for just that occasion. ;-)
I'd go for smaller barrel diameters, for stuff like tomatoes, potatoes or tennis balls. Use a golf ball sized barrel for AP. Gee, does anyone make oversized paintball rounds?
Problems Are: 1. I don't have any old 25-gallon+ tanks to use for the receiver.
2. I don't trust my welding skills enough to put a pipe stub and bolt flange on the end-shell of a tank, and then pressurize it to 125 PSI - at least, not with people standing within 1/4 mile.
3. The expense of developing a proper EPS Foam sabot for intact tomato delivery, at least intact till it arrives on target ...
-->--

Oh...Punkin Chunkin...I saw that on discovery channel and the Myth Busters. Cool stuff. I didn't make the connection because I'm looking for something with only 1/2" diameter.
Jason