Completion of the Blast Wall project. I attempted to detail the plane plastic card wall using Apoxie Sculpt cut with water in a similar fashion to how UltraWerke uses green putty and acetone. Unfortunately, the Apoxie would not dissolve in water despite how mushy the epoxy may become in the presence of H2O.
Plan B was to use Foam Coat from Hot Wire Foam Factory with a bit of play sand. The mix was applied in a very thin, watery coat to the smooth surfaces of the blast wall. Once dry, the sand/plaster mix added a concrete type finish to the model. I would have preferred the epoxy finish because when a mold is created from this item, most of the plaster detailing will stick to the RTV, requiring a bit of re-detailing if a second mold is made.