I started to make them out of posterboard, but the tabs got tedious so I scrapped the first build and redid them again using the template I made and cutting them out of Foam board. The recessed panels on the walls are double laminated posterboard cut to the width of a ruler and spaced apart on the foam board. Last I cut thin strips for the edges of the foam board and glued them in place. I will post the enclosed bay next posting. The enclosed bay area is perfect for protection of the model and the small pieces as well as being able to enclose it with thin clear plastic to protect it from dust, but that is another project.