This particular diaphragm valve spud gun was actually a "junk gun", made from miscellaneous parts that I had on hand
in my PVC parts box. This gun still uses the same diaphragm setup that our other guns use, the only thing is this one
is totally sealed up, no screw on end caps, etc. Like I said, this was a scrap parts gun. This gun uses a tee
as the center of the gun body, with the air chamber tube extending through the tee. The bottom part of the tee has a
piece of PVC pipe in it that has a groove cut in it to house the blowgun nozzle, basically inside the pistol grip. As
the pics show, everything is contained inside an all PVC body.
|The completed diaphragm spud gun, painted black
As you can see, the complete spud gun uses no wood for stocks, it is completely made of PVC. The blowgun nozzle
is housed inside the stem of the tee that makes up the pistol grip. The hose barb protrudes through the end cap and
the house bends back up to the hose barb in the end cap that is glued in place on the rear of the gun.
|Big bore blowdart embedded through 1/2" plywood
I did some test firing with some "Big Bore" blowdarts, which have a diameter of .625", just a tad bit more than the inner
diameter of the 1/2" PVC pipe. By these darts being able to have a snug fit in the barrel, the projectile was able to
be accelerated to a pretty high velocity with a large amount of kinetic energy. From a distance of about 15 yards, with
a pressure of 100 psi, the spud gun was able to blow the dart through a 1/2" piece of plywood. As you can see from the
pic, the dart was driven through the plywood.
Plans for this gun are available through Amazon.com in Kindle format. Just click on the picture above to take you
to the Amazon listing in order to purchase.