Wet Film Thickness (WFT) Calculator.
Calculate the required wet paint thickness to apply during painting to meet engineering dry film thickness guidelines.
Coating Specifications
Added thinner evaporates, requiring a thicker wet layer to meet DFT.
Formula: `WFT = (DFT × (100 + Thinner%)) / Solids%`
The dotted blue region represents the wet film. Solid paint layers settle to the darker blue height as solvents bleed out.
Understanding Wet Film Thickness.
What is WFT?
Wet Film Thickness (WFT) is the thickness of a coating immediately after application, measured before any solvents or water evaporate. Measuring WFT is critical because once a coating cures, its thickness will decrease as the liquid solvent disappears.
WFT is typically measured using a **notched wet film comb** pressed perpendicularly into the wet coating immediately after spraying or rolling.
Thinner adjustments
Paints are often thinned (using water, mineral spirits, or xylene) to allow clean atomization in sprayers.
Thinners add liquid volume during application but evaporate entirely during curing. Consequently, if you dilute paint by 10%, you must apply a 10% thicker wet coat to achieve the same target dry layer thickness.