Homebrew PCBs

I thought about the same method with using syringes, my wife is a 
nurse.  I have seen some demos of pbc supply houses where they use a 
plotter with a air pressure operated needle to place solder paste, 
screen print liquid and solder mask on boards.

My thought is to use screen print ink or liquid conformal coating in 
the syringe and deposit it by setting the z axis on the cnc plotter 
to dispense the medium.  You would not have to thin it out, just set 
up a separate stepper on the Z axis to press the plunger.  Should 
give good control over the medium.

Just though of something.  What if you did the above,  but deposited 
etching paste to start etching the areas you did not want.  After 
laying down the paste, you could spray the board with acrylic/enamel 
paint as a mask, dry a few minutes with a hair dryer, wash the paste 
off then do your etching.  I will try latter today if I can.

Brian G.