Curling plaster cloth:
Joe F. prefers masking tape as a base scen-
ery form instead of plaster cloth. Rio Grande Dan advises using
a water-resistant exterior glue, like Titebond II PremiumWood
Glue to hold down the plaster cloth. Paint down a generous
3-inch wide layer, then press the plaster cloth into the glue and
let it harden. Plaster cloth must be applied drippy-wet to get a
lasting bond. Water-based ballast glues shouldn’t ruin plaster
cloth scenery once it has dried. A second layer of plaster cloth
may be needed to get a rigid, nonporous structure.
Glue:
In his question, Mike mentions a 3:1 glue to water ratio
but several commenters said this is backwards. Elmer’s Glue
dries clear and a little flexible. It works well in ratios from
four to two parts water to one part glue. Experiment on a test
patch. Too much glue and the adhesive doesn’t flow into the
cracks and crevices in the ballast. Too much water and you
have to deal with loose grains of ballast. If your glue beads up,
the ballast hasn’t been dampened thoroughly.
Wetting agents:
Dishwashing liquid, alcohol and Rain-X were
all mentioned. Just a tiny amount is needed to make the glue
mixture flow into the applied ballast. Too thick of a glue mix-
ture can make ballast clump and ball up.
Ballast materials:
For years, wood products like bits of cork and
crushed walnut and pecan shells were about all that was avail-
able, though you can go back into the 1950s and find reference
to roofing granules. In the past couple of decades, modelers
have adopted commercial crushed rock products that can be
sifted to provide several grades of material, and are available
in several colors. Others make their own by sifting crushed rock
or paver sand. Acrylic washes can be used to color ballast. Two
reliable suppliers of real rock ballast are Scenic Express and
Arizona Rock and Mineral.
