Abstract: A structural panel has one or more face sheets bonded by adhesive layers to a core body having two outer plastic liner sheets fusion-bonded to linear ends of inner plastic truss elements spaced apart with open spaces therebetween extending in a plane direction of the plastic liner sheets. The sheet-to-sheet adhesive bonding provides a high-strength laminate bonding that is very resistant to delamination, simple and inexpensive, and can be carried out by a preferred continuous sheet bonding technique. The all-plastic core body is highly resistant to moisture attack, and the open spaces between truss elements provide flexibility to accommodate thermal expansion and contraction. The truss construction of the core body provides high compressive and shear strength, while minimizing the amount of material required to be used. In one preferred embodiment, two metal face sheets are used, and the core body has plastic liner sheets fusion-bonded to a corrugated plastic core sheet.