SpudFiles

I have recently decided to make a small diaphram valve cannon. Thus, being my first diaphram cannon is the reason for the smaller size. I'm making it almost exactly to plans of the "Atom Project" cannon, with a few minor changes. It will have a 1 1/4"x 14" chamber and a 1/2"x about 13" barrel. I had a few questions about this diaphram valve that I thought you could help me with. I am going to use a threaded clean out in the back of the chamber to give me access to the diaphram just incase of some difficulties. I was wondering about the exact placement of the valve. should the diaphram be in with the threads so when the cap is screwed on, it pushes the valve against the barrel? Or should there be a gap between the cleanout coupler and the barrel? If so how big of a gap? I did a search on google to find someof the answers I had and found most on this site- http://www.thebugshop.org/othersites/ai ... ud_op.html - I was just wondering if the information presented on this site are accurate to go by. Thanks in advance for help.

Nick

please dont use a cleanout, use a pressure rated (nsf-pw marked on fitting) threaded plug, cleanouts are DWV and are not safe, they've even blown on combustions

as for the valve placement, make the barrel long enough to be at about the place where the plug wont go in anymore (good way, count the threads on the plug that went into the female, then count up that many threads in the female adapter, and stop the barrel there) from the inside of the female adapter, taht way you just put in the phragm, and screw in the plug, that will keep the phragm in place. yes the plug should push the phragm against the barrel, but it shouldnt push it too much.

also i wouldnt use just a hole to shove a blowgun in, you should really tap a 1/8" hole for a schrader valve, and a 1/4" hole for a ball valve, or use one 1/4" hole, and use a tee and a reducer to attatch both the schrader and the ball valve for exhaust.

another thing, dont use a bell reducer, use a coupling and bushings, that are NSF-PW. and solvent weld, dont just glue http://www.burntlatke.com/weld.html

ok thanks for the advice. I wasn't planning on using a cleanout sorry for the miscomunication. I must have had a brain fart or something. And I was also planning on doing the schrader valve ball valve setup. If i can avoid it I never use bell reducers. The tee Idea sounds much better then what I had in mind, I'll do that instead. Thanks again for the helpful information. It is greatly appreciated!

Nick