Meaning and use

5.1 Natural weathering tests can take years, and accelerated weathering assessments often take weeks or months to obtain useful data. Associating board selection with desired weatherability characteristics helps paint experimenters maximize information over the desired time frame.

5.2 Because exposure testing requires a long time span, the importance of planning robust experiments while controlling for as many variables as possible cannot be overstated. For this reason, it is very important to choose a test board made of a representative wood species or composite, grade of wood and type of surface intended to be painted.

5.3 This practice can be used with any type of exterior architectural paint for wood or wood composite substrates, such as exterior paint, primer, wood colorant or water repellent.

ASTM D7787-13 Standard Practice for Selection of Wood Substrates for Evaluation of the Weather Resistance of Architectural Coatings

Step 1: Scope

1.1 This practice provides guidelines for the selection of wood or wood composite substrates for evaluating specific weatherability characteristics of architectural coatings such as exterior coatings, primers and deck finishes.

1.2 The procedure includes selection of wood species and selection of individual wood test boards by visual inspection of wood characteristics.

1.3 This practice is designed to cover wood substrates commonly used in weathering research for architectural coatings. It is not intended as a comprehensive guide for all wood species and can be used to assess the weatherability characteristics of architectural coatings.

1.4 Values expressed in SI units or inch-pound units shall be treated separately as standard values. The values stated in each system may not be exactly equivalent; Therefore, each system should be used independently. Combining values from two systems can result in non-compliance.

1.5 This standard is not intended to address all safety concerns (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.