Effect of Internal Stresses on Bond Strength of Wood Joints.

摘要

A method was developed to evaluate how different adhesives respond to internal-stress development as wood substrates change dimensions with moisture changes. Two compression shear specimens were used--one with crossed-grain hard maple adherends that developed high internal stresses,and the other of parallel-grain white pine that developed only moderate internal stresses. Use of this method with seven different adhesives showed a phenol-resorcinol, a gap-filling phenol-resorcinol,and a urea-resin adhesive to be highly effective and about equal in their ability to resist the effects of internal stresses. An epoxy was moderately effective, a catalyzed polyvinyl acetate still less effective,and casein and an uncatalyzed polyvinyl acetate were incapable of resisting wide fluctuations in internal stressing.