I'm makin a cannon its built but I'm havin trouble makeing a diaphragm for it, the valve type is more or less a super enlarged orbit watermaster 57101 valve http://i4.photobucket.com/albums/y132/The_Ogre/basicdiagram.jpg here is the main style of the valve it is buit off a 4" Genvoa test T w/ a 2" b...