How Does Cold Weather Affect Paint Curing?

Viscosity

• As the temperature of paint drops, the consistency of the paint thickens. Thick paint can be troublesome to work with, as it smooths on in a heavy layer. Thick, heavy paint can reflect brush marks, is susceptible to sagging and can negatively affect the curing process.

Surface Imperfections

• Cold temperatures result in heavier paint that when applied, can result in a variety of surface issues. Textured or a visibly brushed finish may appear when applied with a paint brush. Cold paint that is rolled on often results in a surface containing air bubbles and stippled peaks. Because cold temperatures affect the elasticity of the paint surface, called the paint film, breaks and cracks in the paint surface can also appear.

Adhesion

• Paint contains a bonding agent that reacts to heat and helps the paint to adhere to the substrate. When the surface is cold, the chemical bonding agent is often not properly activated, and instead of sticking to the surface of the project, the paint is actually suspended or stretched over the surface. The result of the lack of adherence is a paint that will not properly cure to the surface, but will eventually harden to some degree in a suspended state. The structure of the paint will be compromised and the paint will eventually chip and flake away.

Curing Time

• Paint curing is not the same as paint drying. Drying is an evaporative process where water is extracted from the paint and in turn, the paint hardens. Curing is a chemical reaction that activates the bonding agent in the paint that adheres the paint to the surface being painted and produces the paint film, or surface of the paint. Cold temperatures impede the curing process. It slows the dry time and prohibits the necessary heat-producing chemical reaction needed to activate the bonding agent. With time, paint that is applied in cold temperatures may cure, but it may not cure completely or may cure improperly, resulting in damaged paint film which can be unattractive and provide an inferior moisture barrier.