What is dry film thickness and why is it important?

• A. The thickness of the coating before drying; ensures color accuracy.
• B. The amount of paint wasted during mixing.
• C. The thickness of the coating after drying; ensures adequate barrier and durability.
• D. The number of coats applied.

Answer: (C)

Dry film thickness is the thickness of the coating after all solvents have evaporated and the film has cured. This solid film is what provides the protection and appearance on the surface. Because the coating’s performance—its barrier against moisture, chemicals, and weather, as well as its durability and abrasion resistance—depends on that thickness, meeting the specified dry film thickness is essential. If the DFT is too thin, the coating may not protect adequately or last as long; if it’s too thick, it can cure improperly, crack, peel, or waste material. In practice, you measure DFT with a thickness gauge to ensure you meet the project’s specifications and the coating manufacturer’s recommendations.