Meaning and Purpose

5.1 As the brush resistance of the paint increases, any natural tendency of the painter to overapply the paint will decrease. When all other factors are held constant, increasing brush resistance will result in greater film thickness, resulting in improved durability and concealment. On the contrary, it may sometimes be preferred to use a lesser degree of brush drag for easier application (i.e., using a lesser degree of brush drag reduces the time and effort required to apply paint to a particular area).

5.2 This test method provides a standardized spawning procedure for assessing brush resistance as an alternative to the customary informal temporary procedure. The goal is to increase the reliability and precision of determining this feature as much as possible.

Note 1: Brush drag of paint is directly related to its high shear viscosity. There is generally good ranking order agreement between the results obtained by this method and the test method D4287. The sensitivity of this brushout method has been found to be sufficient to distinguish brush rates corresponding to high shear viscosity differences of not less than 0.3 poise (0.03 Pa.s). The cyclic data show that the ranking order agreement between the brush and viscosity methods is poor when latex and solve-based coatings belong to the same comparison group. This is due to the fact that the two paint types have significantly different rheological properties that can affect the relative perception of brush resistance. four

ASTM D4958-2016 “Comparison of Brushability of Latex Paint”

Scope of

1.1 This test method is a standardized brushing procedure for comparing brush resistance of architectural solvent-based coatings.

1.2 With slight modifications, this test method is also applicable to solvent-based coatings.

1.3 Values expressed in SI units shall be regarded as standards. The values given in parentheses are for reference only.

1.4 This standard is not intended to address all safety issues, if any, associated with its use. It is the responsibility of users of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory restrictions prior to use.