In the coating of concrete structures, the concepts of dry film thickness and wet film thickness are usually involved. The conversion between the two can be done using the following methods:
Dry Film Thickness (DFT) refers to the film thickness of a coating after it has fully cured and dried. It is usually expressed in millimeters (mm) or microns (μm).
Wet Film Thickness (WFT) refers to the thickness of the wet surface of the coating during the coating process, which has not yet dried and cured. Wet film thickness is usually expressed in millimeters (mm).
To convert between dry film thickness and wet film thickness, a parameter called "conversion rate" or "solids content" can be used. This parameter represents the proportion of volume reduction of the coating during drying.
In general, the conversion relationship between wet film thickness and dry film thickness is:
DFT = WFT/conversion rate
Conversion rates are provided by the paint manufacturer and are usually expressed as a percentage. For example, if the conversion rate is 50%, the dry film thickness will be half the wet film thickness.
Conversion rates vary according to the characteristics of the paint and the composition of the solids, so the exact values provided by the paint manufacturer should be used in practical applications. Proper control of wet film thickness is critical when performing painting work, as dry film thickness is obtained by converting wet film thickness and conversion rate. Accurate measurement and control of wet film thickness ensures that the final dry film thickness meets design requirements and paint manufacturer recommendations.
