If you are looking for a material you can cut and carve easily, can be joined with white glue, scenic cement, a hot-glue gun, or superglue, and can be painted with water- and solvent-based paint, check out Green Stuff World’s Phenolic Carving Foam.
Lightweight, but strong, the material is perfect for making walls or other structures on a diorama and slices cleanly with a hobby or utility knife. It can be textured by carving it with scribers or knife; you can also press objects into it. Each 8¼- x 11¾-inch sheet is 10mm (.4 inches) thick and has a slight texture that can be quickly smoothed with a coarse sanding stick. A coat of primer will seal the surface. I can think of so many uses for this material and having it means I am ready to get a couple of stalled diorama projects back on the bench.
Safety notes: Carving and cutting produces a fine dust that is an irritant, so wear a respirator or dust mask when working with it and wash your hands after handling. Also, wash any metal tools used on the material as the chemicals can corrode them.
Note: Hotwire cutters will not work on phenolic foam because it is heat resistant up to 300 degrees Fahrenheit.
~Aaron Skinner, Editor of FineScale Modeler