For products that are typically coated by dipping, Practice B uses a motor-driven device to withdraw a test panel from a container of liquid coating at a constant, controlled speed. The withdrawal rate is the primary factor determining the final film thickness.
ASTM D823: The Standard for Producing Uniform Film Thickness astm d823
Standard Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels For products that are typically coated by dipping,
This method uses an automatic spray machine to apply coatings. By controlling the speed of the spray gun, the distance from the panel, and the atomization pressure, technicians can achieve a highly precise and repeatable film. This is often used for automotive and industrial finishes where spray application is the real-world standard. Practice B: Motor-Driven Dip Coater By controlling the speed of the spray gun,
For a given wet-film applicator gap (G) and coating’s volume solids (VS% as a decimal), the theoretical dry film thickness (DFT) is:
Whether testing for corrosion resistance, color accuracy, or durability, a non-uniform film can lead to skewed data and unreliable results. ASTM D823 provides the methodologies necessary to eliminate human error and variability in the application process. Why Uniform Film Thickness Matters