Shaping Air Basics

Shaping air pushes paint toward the part and defines the spray pattern. Without shaping air, paint spray would go sideways – away from the part - as it comes off the edge of a rotary bell cup.

Automated paint lines or spray booths often have rotary bell atomizers that use dual shaping air.

Dual shaping air involves two rings of passages that surround the bell cup at the front of the applicator. Air from the inner ring and air from the outer ring differently affect the paint as it flows from the edges of the bell cup.

• Inner shaping air captures and propels paint to the part. It produces a large pattern with a soft spray.
• Outer shaping air acts as a guide, narrowing wide patterns made by inner shaping air. Outer shaping air produces a tight pattern with a strong spray. 

Dual shaping air offers good pattern control and adjustability. By having two shaping airs, you can get into corners and small spaces. 

Like dual shaping air, blended shaping air uses inner and outer shaping air. However, it more effectively blends the shaping airs together for better pattern control and adjustability. This not only increases transfer efficiency, it also improves overall finish quality.

Blended shaping air works especially well for finishing many different parts and complex shapes.

The Graco ProBell is the only rotary bell atomizer that produces blended shaping air. 

The Faraday cage effect happens when you’re trying paint into corners with an electrostatic gun. Charged paint spray is attracted to the closest grounded area of the part - not the corner.

One way to combat that is to reduce the voltage of your applicator and increase the air pressure. This allows the shaping air to direct the paint into the corner.

The Graco ProBell has a system control that allows you to preset changes in applicator voltage and air pressure. If a part with corners comes along the paint line, you can switch to a setting meant for going into corners and avoiding the Faraday effect.