Water Gun Construction

Schematic of water gun barrel.

This is a two to one scale drawing of my attempt to reproduce the launcher described in the patent.  The muzzle end of the barrel is formed from a 1.5" length of 3/32" ID X 3/16" OD high alumina ceramic tubing (basically sapphire, actually closer to 13/64" OD).  The breach end is made from a 9/16" length of 3/32" ID X 3/16" OD 304 stainless steel tubing.  The breech is closed with a 0.5" length of 1.5" OD polycarbonate rod carrying a 1" length of 0.040" OD tungsten welding electrode.  The ceramic tubing is epoxied into a 1.25" length of 1.5" OD polycarbonate.  The stainless steel tubing is press fit into a 3.625" X 1.5" X 0.0625" copper sheet and slip fit into a 3" X 1.5" X 0.5" polycarbonate block.  The pieces are all held together with three threaded nylon rods.  The bottom of the rectangular block is drilled and tapped to accept the 3/8-16 terminal of my big pulse capacitors (see photos below).
Exploded view of water gun.
This is a photograph of the pieces partially assembled.
Assembled and mounted water gun.
This is a picture of the assembled water gun mounted on my capacitor bank.  To the left of the picture is my triggered spark gap.  In operation, the output from the triggered spark gap (off the top of this photo) is connected to the center electrode of the gun via an air core inductor.  The capacitors are charged and fired just as in my can crusher.