After the first layer begins to harden more Hydrocal was applied with a wide brush. Since Hydrocal sets up quickly you must work fast. If the brush gets "rock hard" you can remove the plaster by pounding the bristles with a hammer. Here you can see the grid and crumpled paper forms covered with plaster cloth and additional coats (whatever it takes) of plaster. The resulting "hardshell" scenery is very rigid and strong.
Back to the layout construction...The scenery contours are formed using the cardboard strip grid method (left) or crumpled paper (right) covered with plaster-cloth or plaster and towels. That would be Hydrocal plaster of course. You can buy Hydrocal in 100# bags at many building supply and ceramic or tile supply companies. I was fortunate enough to be given about 60# of Hydrocal by another modeler. I'll probably use about 30-40# in all and a lot of that is waste.
