Application of polyurea with high pressure equipment such as GRACO E-XP2 or H-XP3 requires mandatory personal protection, cautious material handling, and precise machine operation. Key measures include wearing a supplied-air respirator, maintaining balanced fluid pressures, and ensuring the substrate is completely dry. If not sure how to handle these parameters you can always see assistance from AEMCO, as they are authorized distributors and service providers for GRACO high pressure equipment for spraying Polyurea
Personal Safety and Health
- Wear full-face masks with supplied air or double-filter organic vapor respirators, especially in enclosed spaces.
- Put on isocyanate-resistant chemical gloves (like nitrile or viton), protective coveralls, and safety boots.
- Keep eyewash stations and emergency spill kits close to the work area where spraying take place.
Equipment and Pressure Management
- Operate high-pressure plural component spray machines (such as Graco systems) at recommended pressures typically 135 to 170 bar (2,000 to 3,000+ PSI).
- Check that component A (isocyanate) and component B (resin) pressures stay balanced within 10% of each other to prevent poor mixing.
- Heat the individual components and hoses to the manufacturer’s target levels (often 50–77°C / 120–170°F) to control viscosity.
- Release all system fluid pressure completely before attempting any maintenance, cleaning, or opening of lines.
- Try to purchase an equipment which is fool proof as they will prevent machine from working with wrong ratio or temperatures.
- Relative Humidity (RH); must be less than 85% (some technical data sheets require less than 80%). While pure polyurea handles moisture better than polyurethane, excessive humidity risks flash condensation on the substrate.
- Dew Point Rule is the most critical calculation. The temperature of the substrate must be at least 3°C (5°F) above the calculated dew point and rising. If it falls below this margin, invisible micro-condensation will trap moisture under the coating, causing blistering or peeling.
Material and Environmental Control
- Keep containers tightly sealed and dry; moisture contamination in isocyanate drums causes dangerous pressure buildup.
- Verify substrate moisture content using standard testing methods to avoid bubbling or blistering of the coating.
- Avoid spraying if wind speeds exceed 25 km/h, which causes loss of heat and poor surface texture.
Standard Environmental Limits
- Ambient Air Temperature: The safe application envelope spans from -20°C to +40°C depending on the specific product formulation (such as Sika Sikalastic), but 10°C to 32°C is preferred for consistent processing. [1, 2]
- Relative Humidity (RH): Must be less than 85% (some technical data sheets require less than 80%). While pure polyurea handles moisture better than polyurethane, excessive humidity risks flash condensation on the substrate.
- The Dew Point Rule: This is the most critical calculation. The temperature of the substrate must be at least 3°C (5°F) above the calculated dew point and rising. If it falls below this margin, invisible micro-condensation will trap moisture under the coating, causing blistering or peeling. [1, 2, 3, 4, 5]
Consequences of spraying Out of Specified Parameters:
- Too Hot (>35°C ): The polyurea gel time (already a rapid 10–15 seconds) accelerates drastically. The material can cure mid-air before hitting the surface, resulting in a rough, uneven texture and poor leveling.
- Too Cold (<10°C): High-pressure machines will struggle to maintain balanced fluid pressures because the components thin out less efficiently, leading to poor mixing. Curing times slow down, making the uncured layer vulnerable to moisture pickup.
- Excessive Humidity (>85% RH): Condensation forms rapidly on cold steel or concrete. Water acts as a release agent, completely destroying the bond strength between the substrate and polyurea membrane.
It is always better to buy the equipment from an authorized GARCO distributor like AEMCO in Saudi Arabia, they assist you with delivery, installation & training. They also take care of the warranty provided by the GRACO.