The nozzle cap is one of three essential pieces on an internal mix airbrush. The nozzle funnels the speeding air around the nozzle and focuses a low pressure zone just in front of the nozzle’s tip. This low pressure zone pulls the paint out of the airbrush to be atomized when it hit’s the air stream.
For the engineers among you, this cap is a venturii nozzle.
Paint can build up inside the tiny hole. Here’s how to clean it out.
Everything else can be cleaned with a cotton swab dipped in cleaning solution.
Got bubbles in your color cup or bottle? Try making sure this piece is tightened all the way. (Don’t over tighten it or you’ll have a heck of a time getting it back off).
Why? The low pressure zone needs to be in a certain spot to pull the paint most efficiently. It can take some slight variations in location but, for the most part, just screw the nozzle cap all the way on and don’t play with it.
Many airbrushes let you remove the nozzle cap to get a stipple effect (really big uneven dots) You will need to turn up the air pressure to get it to work though.