TheDoctor
Sr Member
It is the square button on the left side of the pistol on the vertical metal tube, if that is what you are referring to as the valve assembly. Not a good weapon for south paws!
Are you sure? There looks to be a trigger right where you'd expect one... A small black piece that protrudes from frame.
Also, I have some of those vacuum tubes and they are VERY fragile and fairly hard to come by (even 'dead' ones). Smaller tubes are pretty plentiful. The larger tubes are from TVs.
You might have something with using a hacksaw as the frame, then wood as the handle.
Though this all may be moot. You might just want to wait a few weeks (no inside knowledge, just a hunch)...