The mechanical properties of commingled plastic in the form of thick beams prepared by the ET-1 process have been examined in flexure and compression. The mechanical properties were evaluated in relationship to the hierarchical morphology described in a previous study. It was found that the flexural modulus was dominated by the properties of the skin and was satisfactorily modeled by approaches based on the observed micro-morphology, such as the Nielsen and Davis models. It was not necessary to consider the skin-core macro-morphology because the flexural modulus was dominated by the void-free skin. The compressive modulus was lower than the flexural modulus and was strongly affected by the skin-core macro-morphology. From the difference between the flexural and compressive moduli, it was determined that the core was essentially nonload-bearing in compression. Flexural fracture initiated on the tension side of the beam and propagated rapidly through the thickness, whereas compressive failure occurred by longitudinal splitting of the skin.