13 / Jun / 2023
Troubleshooting: spraying water-based coatings in warm weather
When it comes to the application of water-based wood coatings in industrial settings, weather conditions play a crucial role in achieving optimal results. While these coatings offer numerous benefits, such as reduced environmental impact, improved worker safety and quick drying times, they can present unique challenges when applied during hot weather.
In this blog post, we will explore the technical difficulties that arise when spraying industrial water-based wood coatings in hot weather and discuss potential solutions to overcome them.
Accelerated Drying Time
One of the primary challenges of spraying water-based wood coatings in hot weather is the accelerated drying time. High temperatures increase the rate at which water evaporates, resulting in faster drying of the coating. This can lead to problems like uneven finish, streaking, or reduced levelling. Additionally, the rapid drying time may limit the ability to achieve a smooth and flawless surface.
Solution: To address this issue, it is crucial to make adjustments to the spraying equipment and techniques. Increasing the application viscosity or adding retarders to the coating can slow down the drying process, allowing the coating to level properly. Get in touch with the team and ask about drying available retarders. Moreover, utilising equipment with fine atomisation capabilities can help to achieve a uniform finish even in hot conditions.
Reduced Open Time
Open time refers to the period during which the coating remains wet and workable after application. In hot weather, the reduced open time of water-based wood coatings can make it challenging to achieve even coverage and proper adhesion. The coating may start drying before it can flow out and level, leading to issues like brush marks or lap marks.
Solution: Extending the open time of water-based coatings can be achieved by adding flow additives or conditioners. These additives increase the wetting and flow properties of the coating, allowing it to spread smoothly and self-level. Adjusting the application technique to minimise the time between spraying and levelling can also help overcome this challenge.
Increased Risk of Overspray and Atomisation Issues
Hot weather conditions can exacerbate issues related to overspray and atomisation when spraying water-based wood coatings. As the temperature rises, the air becomes less dense, affecting the spray pattern and droplet size. This can result in excessive overspray, reduced transfer efficiency, and uneven coverage.
Solution: Employing spray equipment with adjustable pressure, air volume, and fan width can help to compensate for the changes in air density. Fine-tuning these parameters ensures proper atomisation, reducing overspray and improving transfer efficiency. Additionally, utilising spray booth systems or proper ventilation can minimise the impact of external air conditions on the spraying process.
Increased Risk of Blushing
Blushing, also known as water spotting or water ring, occurs when water-based coatings dry too quickly in high humidity. In hot weather, increased humidity levels can make it challenging to control the moisture content on the surface of the coating, resulting in blushing issues. Blushing manifests as a milky or cloudy appearance on the surface, diminishing the overall aesthetic quality of the finished product.
Solution: To mitigate blushing, controlling the environmental conditions is crucial. Maintaining a consistent humidity level and proper airflow within the spraying area is essential. Additionally, using dehumidifiers or air conditioning units can help to regulate humidity levels, minimising the risk of blushing.
Conclusion
Spraying industrial water-based wood coatings in hot weather presents several technical challenges that need to be addressed to achieve desired results. By understanding and implementing appropriate techniques and adjustments, such as modifying viscosity, extending open time, adjusting spraying parameters, and controlling environmental conditions, these difficulties can be overcome. With the right approach, industrial wood coating professionals can ensure high-quality finishes, even in challenging weather conditions, and continue to harness the benefits of water-based coatings in their operations