Double Action Airbrush beginner

I’ve used a single action airbrush (Paasche H) for 2 years, and gained enough experience and confidence to try a double action model. My local hobby shop only sells Paasche, so I recently bought a VL. Is the Head Protecting Cap supposed to be on the airbrush while painting, or is it only to protect the needle when not being used? I tried it both ways and got finer lines with it on, however, dried paint started to build up on it.

Scott

Take the cap off, it is for protection only.

Mike