A process for forming a fiber reinforced core panel which is able to be contoured includes the following steps. First, slice a sheet of a low density material a plurality of times in a first direction of the sheet on at least one side, where the slices extend through only a portion of the thickness of the sheet, then divide the sheet in the second direction of the sheet into a series of low density strips having at least three faces (major face, a first edge face, a second edge face, and optionally a minor face) where the slices in the sheet form a series of cuts in the major or minor face of the low density strips. Next, arrange the series of low density strips to form a core panel and thread a continuous fibrous reinforcement sheet through the low density strips such that the fibrous reinforcement sheet is disposed between adjacent strips and adjacent to the major or minor faces of the low density strips.