The basic principle is creating a pressure difference. As the air passes around the nozzle, it exits the Airbrushing at high speed. The pressure in that area is lower than the atmospheric pressure surrounding the brush. As we open the paint flow, physics (for lack of a better word) tries to equalize the pressure.
The airflow is regulated by the paint flow. The more you increase it, the more air comes in and thus a stronger pressure difference is created.
What is the science behind airbrushing?
This means that as you turn up the paint flow, the Airbrushing ‘blows harder’ because there’s now a higher pressure difference to overcome. If you continue turning up the paint control whilst still holding down the trigger, at some point you’ll blow through your paint (start spraying clear fluid).
At this point, if you reduce the paint flow by half, there’s now a stronger pressure difference again and it shoots twice as far. Health and Safety Online Training Courses in the UK.
This is why brushers always need to turn down their paint flow before stopping! If they forget, they just blow through the paint and have to wait for it to dry.
The airflow is also affected by needle position. If you spray whilst pulling back on the trigger, then there’s a long gap before the nozzle opens up, so more of an area of low pressure will be created at first which will increase your range.
If you spray whilst pushing forward on the trigger (and thus starting with a shorter gap and weaker pressure), then you will get less range, but it’s easier to paint fine details.
Conclusion:
You can also change how hard the Airbrushing ‘blows’ by using different nozzles or needles – I use a 0.2mm needle when detail painting, but a 0.5mm needle when covering larger areas with opaque paint as it makes for a much softer spray and I have to turn the paint flow down so far that it doesn’t blow through easily.
Hope this helps!
