I’m working on a short series of painted self-portraits at the moment. I’ve mounted a Paasche Flow Pencil (very much like an airbrush, only without the air — the ‘nozzle’ is conical and a needle valve seats in the nozzle in order to control the flow of paint. The Paasche is not a very high-precision device, so fluids which aren’t very viscous (like water) flow out quite fast, even when the valve is ‘closed’.
I suppose I could’a figured this out in advance, but it seemed to me that coffee or tea stained paper would make a good first trial image and clean-up would be very easy… WRONG! WHAT A MESS!
So viscosity about like cream works quite well.
I removed the little paint-pot which came with the flow pencil and replaced it with a water bottle I’d modified for the purpose. The cap has the paint outlet mounted in it and I mounted a vacuum-relief/pressure port (to force more viscous paint to flow using a bit of air pressure) on the side (a tube runs to the ‘bottom’ of the bottle so air can get in). This allows me to fill the bottle with paint (or whatever) without making a mess, mount the cap, and connect the hose to the pen before inverting the bottle and allowing paint to flow. Works well.
Because the pen doesn’t have many parallel surfaces — it’s all cones and curves and joints, it wasn’t easy to conceive a way to hold and actuate it. In the end I decided to make it easier for me to construct the gizmo and so I made it to kinda work backwards (power-off allows paint to flow — so when it stops, paint keeps running). A single solenoid both lifts the pen off the paper and releases the trigger, stopping the ink flow while the pen is moved to a new painting location. When the solenoid is ‘off’, a spring pushes the pen down onto the paper or canvas and actuates the trigger at the same time.
The paper surface on my 2nd attempt is now badly abraded with ‘fuzz-balls’ all over the surface in the darkest areas — next attempt I’ll use a heavily sized paper and adjust the height of the flow-pencil so it JUST BARELY TOUCHES THE PAPER!
I’m VERY excited about the possibilities for color work, both directly (painting flat areas of transparent color), and especially indirectly (using weighted gestures again) since the flow-pencil produces a VERY sharp-edged line — much cleaner edge than my airbrush!