Drying Rate Factors

Drying Rate Factors

Factors Affecting Drying Rate of Architectural Latex Paints

Weather/Air Conditions

Humidity: High relative humidity (moisture content in the air) retards evaporation of liquids from the paint; relative humidity over 90% can cause extremely slow drying.
Temperature: Low temperatures impede evaporation of liquids from paint; significant slowing of dry is generally observed with temperatures below 60° F. Painting in direct sunlight can dramatically increase paint temperature (and thus speed of dry) if the paint is a dark color, which absorbs heat from the sunlight.
Wind: Air movement speeds drying because fresh air passing over a wet paint film helps liquids in the paint to evaporate; dry times are generally specified assuming little or no air movement.

Application

  • Application of the paint in a thick film will retard drying.
  • If the paint is cold during application, it causes it to go on heavy and this increases dry time.

Surface Characteristics

  • All else being equal, paint on a porous surface will dry more quickly than it will on a sealed surface because some of the liquid is absorbed by the surface.
  • A warm or hot surface will contribute to speed of dry.

The Paint Composition

Factors contributing to high-film build.
  • High viscosity: high thickener content of high solids content.
  • Nature of the thickener used in making the paint
Factors that hold onto water longer.
  • Nature of the binder: vinyl-acrylic latex dry more slowly than all acrylic or styrene acrylic types, all else being equal.
  • Nature of the thickener: cellulose types may hold onto water more so than do some synthetic thickeners.
  • Solids content: at equal wet spread rate and all else being equal, a lower solids paint takes longer to dry than a higher solids paint because there is more liquid to evaporate.
 
For further information on factors that affect drying rates, contact your Diamond Vogel representative.