The aim of this research was to evaluate the quality of plywood made from wood veneers of Sequoia sempervirens. Plywood with five 2.0 mm thick veneers were produced in laboratory and bonded with phenol-formaldehyde resinusing two different formulations: (A) resin = 100, extender = 5, filler = 5,and water = 5; and (B) resin = 100, extender = 15, filler = 15, and water = 15,with two different amounts of glue spread: 280 g/m² and 320 g/m². The panels were pressed with specific pressure of 10 kgf/cm², temperature of 130 ºC, and pressing time of 10 minutes. The properties of the glue line shear strengthand static bending (modulus of elasticity and modulus of rupture - parallel and perpendicular to the grain) were evaluated. In general, the different glue formulations and amounts of glue spread did not significantly affect the properties of the panels,which represent an important aspect from the economic point of view. The shear strengthand percentage of wood failures of the plywood produced withformulation (B) met the minimum requirements of the EN 314-2 (1993) standard to panels for external use. Results indicate that Sequoia sempervirens veneers can be used to compose the core of plywood for external use.
phenol-formaldehyde resin; glue line strength; glue composition