High-solids coatings are widely used in industrial environments because they can deliver high film build with fewer solvent emissions. However, their higher solids content also means higher viscosity, which can make spraying more demanding than conventional coatings. One of the most common responses is to increase pump pressure until the material atomizes. While this may appear to solve the immediate problem, excessive pressure can increase coating overspray, accelerate component wear and place unnecessary strain on the equipment. Effective high-solids coating application is not about using maximum pressure. It is about balancing fluid pressure, material temperature, flow rate, spray tip, hose configuration and application technique.

Why High-Solids Coatings Can Be Challenging to Spray

High-solids coatings contain a greater proportion of coating solids and less solvent compared with conventional formulations. This can produce a thicker, more viscous material that requires more energy to move and atomize.

During spraying high-solids coatings, several challenges can arise:

• Higher viscosity: Thicker materials offer greater resistance to flow and require an appropriately sized pump and fluid path.
• More demanding atomization: Standard pressure settings may not provide sufficient energy to break the material into a consistent spray pattern.
• Pressure-related problems: Increasing pressure beyond the coating’s requirements can create excessive mist, bounce-back and overspray.
• Equipment wear: Continuously operating equipment at or near its maximum capacity can accelerate wear on packings, valves, tips and fluid sections.

Rather than simply increasing pressure, operators should first determine whether the spray package is correctly matched to the coating.

How to Choose the Right Equipment for High-Solids Coatings

Selecting the right high-solids coating application equipment starts with the coating manufacturer’s Technical Data Sheet (TDS). The TDS provides critical information about viscosity, recommended application methods, pressure ranges, temperature requirements, film thickness and compatible equipment.

Match Pump Capacity to Material Requirements

Pump ratio is one factor to consider when selecting high-solids coating equipment. A higher-ratio pump can provide greater fluid pressure, but ratio alone does not determine whether a system is suitable.

Consider:

• Material viscosity
• Required fluid pressure
• Required flow rate
• Application temperature
• Spray tip requirements
• Hose length and internal diameter
• Expected duty cycle

For example, a 50:1 system and a 70:1 system may perform very differently depending on the material and required output. The objective is to select equipment that can deliver the required pressure and volume without continuously operating at its limit.

Check Flow Capacity

The equipment should provide sufficient continuous flow for the selected spray gun and tip. Insufficient flow can result in pressure fluctuations, poor atomization and pump cycling.

A properly sized system should maintain consistent output without excessive cycling or prolonged operation at peak capacity.

Size Fluid Hoses Correctly

Hose configuration can have a significant effect on pressure at the gun. Long or undersized fluid hoses increase friction losses and can restrict material flow.

Using an appropriately sized fluid hose, particularly for long runs and higher-viscosity materials, helps minimize pressure drop between the pump and spray gun.

How to Control Pressure When Spraying High-Solids Coatings

Pressure should be treated as a control variable, not a solution for every spray problem.

During high-solids spray application, operate within the coating manufacturer’s specified dynamic pressure range. Dynamic pressure is the pressure present while material is actually flowing through the system, rather than simply the static shut-off pressure.

If the spray pattern is poor, check the entire application system before increasing pressure. The issue could be caused by an unsuitable tip, restricted hose, low material temperature, inadequate pump capacity or worn components.

Consider Temperature Before Increasing Pressure

Temperature directly affects material viscosity. Some high-solids products become easier to pump and atomize when maintained within the manufacturer’s recommended temperature range.

Where the coating permits it, appropriate fluid heating can help reduce viscosity and improve atomization without relying solely on increased hydraulic or pneumatic pressure.

However, material should never be heated beyond the manufacturer’s specified limits.

Tune the Complete Spray Package

The pump, fluid hose, spray gun and tip must work together. Changing one component can affect the performance of the entire package.

If a system requires unusually high pressure to achieve a usable pattern, investigate the complete setup before simply increasing the pressure.

How to Reduce Overspray During Application

Excessive coating overspray can waste material, affect nearby surfaces and increase exposure to airborne coating particles. Controlling overspray starts with correct equipment settings and consistent spray technique.

Select the Correct Tip and Fan Pattern

The spray tip should be selected based on the coating’s viscosity, solids content, required flow rate and desired fan width.

An oversized orifice can deliver excessive material, while an undersized tip can force the operator to increase pressure unnecessarily.

The fan pattern should also suit the geometry of the surface being coated. Narrower surfaces may require a smaller fan than large, open areas.

Maintain the Correct Spray Distance

For airless application, maintaining a consistent spray distance is important for achieving an even film.

A typical working distance is approximately 12 to 14 inches, but the coating manufacturer’s application instructions should take priority.

Holding the gun too close can increase wet film build and material deposition. Holding it too far away can increase overspray and produce a drier finish.

Keep the Gun Perpendicular to the Surface

The spray gun should remain perpendicular to the substrate throughout the stroke.

Use parallel passes with approximately 50% overlap where specified by the coating manufacturer. Avoid arcing the gun across the surface because this changes the spray distance and can produce uneven film thickness.

Consider Airflow and Enclosure Conditions

Ambient airflow can influence spray pattern, overspray movement and deposition. Ventilation and enclosure conditions should be considered when setting up an industrial coating operation.

Operators should also ensure that appropriate respiratory, skin and eye protection is used according to the coating’s Safety Data Sheet (SDS) and site requirements.

How to Prevent Unnecessary Equipment Strain

High-solids materials can place greater demands on industrial coating spray equipment, particularly when the system is undersized or operated continuously at high pressure.

Choose equipment with sufficient capacity for the expected operating conditions rather than selecting a system that only meets the minimum requirement.

Maintain Fluid Components

Regular maintenance is essential when working with demanding coating materials. Inspect and maintain:

• Fluid-section components
• Packings
• Valves
• Filters and strainers
• Fluid hoses
• Spray tips
• Connections and fittings

Follow the equipment manufacturer’s recommended maintenance intervals and procedures.

Inspect Before Pressurization

Before starting a high-solids application, inspect the equipment for damaged hoses, worn fittings, leaks or other signs of deterioration.

Do not pressurize a system if a fluid hose or component shows signs of damage. High-pressure fluid injection can cause serious injury, so pressure relief and safe shutdown procedures must always be followed.

What Spray Settings Should You Check Before Application?

Before beginning high-solids coating application, verify the following settings and equipment conditions.

Pump Pressure

Confirm the required operating pressure from the coating TDS. Evaluate pressure while the system is flowing rather than relying only on static shut-off pressure.

Spray Tip Size

Select the orifice and fan width based on the coating formulation, solids content, required flow rate and substrate geometry.

Heavy-duty reversible airless tips may be suitable for some high-solids materials, but the exact tip specification should come from the coating and equipment manufacturer.

Hose Length and Diameter

Check both hose length and internal diameter. Long runs and smaller IDs can increase friction losses and reduce pressure available at the gun.

Material Flow Rate

Confirm that the pump can continuously deliver the required gallons per minute (GPM) without excessive cycling or cavitation.

Spray Distance and Technique

Maintain a consistent spray distance and keep the gun perpendicular to the surface. Use controlled, parallel passes with the recommended overlap.

Important: Exact operating pressure, temperature, tip size, flow rate and other specifications should always align with the coating manufacturer’s TDS and the equipment manufacturer’s operating instructions.

Common Mistakes When Spraying High-Solids Coatings

Even experienced operators can encounter problems when application settings are adjusted without addressing the underlying cause.

Increasing Pump Pressure to Compensate for a Poor Spray Pattern

A poor pattern does not always mean more pressure is needed. A worn or incorrectly sized tip, restricted fluid path or unsuitable material temperature may be the actual problem.

Using Undersized Fluid Hoses

An undersized hose can restrict material flow and increase pressure loss. This can force the pump to work harder while still producing inconsistent delivery at the gun.

Ignoring Material Temperature

High-viscosity coatings may become significantly more difficult to pump and atomize when material temperature falls outside the manufacturer’s recommended range.

Where heating is approved, maintaining the specified temperature can improve material flow and reduce the need for excessive pressure.

Compensating for Poor Technique With Higher Pressure

Pressure cannot correct inconsistent spray distance, incorrect gun angle or poor overlap. Application technique must be controlled alongside equipment settings.

Why Choose AEMCO for High-Solids Coating Equipment?

AEMCO provides industrial coating equipment designed to handle demanding applications and challenging viscosity profiles. For projects requiring controlled metering, heating, and high-pressure fluid delivery, systems such as the Graco Reactor, XP-hf Plural Component, XM and PFP Sprayer in Saudi Arabia can provide application-specific solutions when correctly configured for the material and project requirements.

AEMCO can help to evaluate factors such as:

• Coating viscosity and solids content
• Required pressure and flow rate
• Hose configuration
• Material heating requirements
• Spray gun and tip selection
• Expected production rate and duty cycle

The right equipment configuration can help contractors maintain consistent application performance while reducing unnecessary pressure, material waste and equipment wear.

Conclusion

Successful high-solids coating application depends on balance rather than maximum pressure. The right pump, hose, spray tip and material temperature can help achieve consistent atomization without unnecessarily pushing the equipment to its limits. Proper spray distance, gun technique and fan-pattern selection can further reduce overspray and improve film consistency.

Before increasing pressure, check the entire application system. Verify the coating TDS, confirm equipment capacity, inspect the fluid path and make sure the material is within its recommended application conditions.

When equipment selection and application settings are matched correctly, high-solids coatings can be applied efficiently while helping protect finish quality, productivity and equipment service life.

 

H2 : Frequently Asked Questions

●      What pressure is needed to spray high-solids coatings?

It depends on the coating, viscosity, temperature and equipment. Some applications may require 2,500 to 5,000+ PSI, but always follow the manufacturer’s TDS.

●      How can I reduce overspray when spraying high-solids coatings?

Use the lowest pressure that provides proper atomization, choose the right spray tip, and maintain a consistent spray distance and gun angle.

●      Can high-solids coatings damage spray equipment?

Yes. High viscosity and excessive pressure can increase component wear and equipment strain. Proper equipment sizing and regular maintenance help prevent this.

●      What spray tip is suitable for high-solids coatings?

Tip size depends on the coating, flow rate and required fan width. .019 to .027+ inch tips may suit some applications, but always check the manufacturer’s recommendation.

●      How do I choose equipment for high-solids coating application?

Consider the coating’s viscosity, solids content, pressure, flow rate, temperature and hose length. Choose equipment that can handle these requirements without running continuously at maximum capacity.