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How to minimize overspray and reduce adhesive consumption

Applying water-based adhesives, even via the most efficient traditional spray gun technology, can result in a great deal of overspray. What is overspray? Overspray is any sprayed adhesive that doesn’t reach the substrate. This could mean the adhesive landing next to the substrate or diffusing into the air. Minimizing overspray provides a clean and safe working environment and results in a substantially lower adhesive consumption. It is therefore crucial to reduce overspray as much as possible.

There are several ways to minimize adhesive overspray. Choosing the right spray gun is the most important one. Additionally, using the appropriate spray gun settings and proper spraying technique are key.
 

Eric Evers
Author Eric Evers Application Manager

Choosing the right spray gun

Choosing the right spray gun can be a challenging process. There are many different types in the market and the spray gun you choose will completely depend on the technical requirements your product or process has. A spray gun does not only control the adhesive flow, but also determines the width, spray pattern and the air pressure recommended to avoid overspray.

The SABA EZ-mix Green spray gun technology has been specifically developed to prevent overspray. All of the adhesives dispersed from the spray gun is applied to the surface of the substrate to be bonded. In case you work with our EZ-mix Blue spray gun technology, the tips below will help reduce overspray.

SABA EZ-mix Green spray gun technology
SABA EZ-mix Green spray gun

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Applying water-based adhesives on foam

Spray gun settings

After the technical requirements and spray gun are perfectly matched, it is important to use the correct settings. Each process has its own objectives and requirements, consequently, there is no such thing as a one-size-fits-all approach in spray gun settings. However, you can minimize overspray by adjusting the spray pattern, air pressure and adhesive pressure. The right combination of these three aspects ensures the least amount of overspray. Keep in mind that a change in one of these settings generally results in a change in the others as well.

  • Adhesive pressure
  • Air pressure
  • Spray pattern

Adhesive pressure

For 1 component adhesives in particular, adhesive pressure is incredibly important when trying to minimize overspray. With the right adhesive pressure, we can work with less adhesive and let the adhesive do its job better. In general, higher adhesive pressure in combination with the right spray gun settings means more shear forces at the right place. This gives the adhesives a significantly higher tack level.

SABA EZ-mix blue spray gun
Minimize overspray
Minimize overspray

Air pressure

To initiate atomization, we need to ensure that each spray gun has ample air supply. But before we start adjusting the air pressure settings, it is important to understand that the preferred adhesive yield and spray pattern width determine the air pressure needed (PSI/Bar). Applications that require low adhesive volume in a small spray pattern call for low air pressure, whereas high volume applications in a wide spray pattern require higher air pressure. Usually, high air pressure results in more overspray pollution.

Spray pattern

The correct spray pattern must be wide enough to handle a part of substrate, but not too wide to minimize overspray. By adjusting the width setting on your spray gun, you can adjust between a wide or a round/narrow spray pattern. The spray pattern directly depends on the air pressure. When increasing the width, you may also need increase the pressure.

Spraying technique

Operators using the correct spraying technique greatly influences overspray. When applying adhesives, keep in mind that it is advised to keep the spray gun at a distance of 10-20 cm/4-8 inches from the substrate. We suggest using a more narrow spray pattern. This gives you more control over the applied adhesive. Wider spray patterns provide more overspray and a messy workspace. In addition, make sure you spray the adhesive in a ninety degree angle to the substrate. Working at a different angle will cause the adhesive to bounce, causing overspray.

Minimize overspray through operator training

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