ASTM international develops enamel holdout standard.

ASTM International has released a new standard for determining the enamel holdout characteristic of a primer. The standard was developed by Subcommittee D01.42 on Architectural Coatings, part of ASTM International's Committee DO1 on Paint and Related Coatings, Materials and Applications. The primary users of ASTM D7786, Test Method for Determining Enamel Holdout are expected to be manufacturers and developers of architectural coatings.

Keith Alderfer, associate scientist, The Dow Chemical Company, and member of the ASTM committee, says that enamel holdout is an important attribute of an architectural primer. "The enamel holdout characteristic of a primer can have a significant impact on the appearance of the finished painted system, especially if that system is intended to have a semigloss or glossy finish," he adds. "Semigloss topcoats over primers with poor enamel holdout characteristics or unprimed porous substrates can result in lower gloss than is intended from the final coating."

While ASTM D7786 is now completed, the organization welcomes participants to join in interlaboratory testing on the standard that is planned to begin this year.

For more information, visit www.astm.org/JOIN.