EPSILON™ Series, EPS Foam Coating Epoxy | Smooth-On, Inc.
How To Coat Carved EPS Foam Using Habitat Cast N Coat™ Epoxy - YouTube
A one-step method to coat polystyrene particles with an organo-silica shell and their functionalization - ScienceDirect
Terrain idea: Tried to smooth styrofoam, turns out enamel spray and acrylic clear coat have some interesting cratering effects instead. Could be useful. That said, like any spray painting, do it outside.
White Styrofoam/polystyrene/eps Foam Block 12 X - Etsy
Hot Wire Foam Factory All Purpose Foam Coat, 25 lbs.
HARD COATING LIGHTWEIGHT FOAM BOULDERS - YouTube
Smooth Foam Bells Available in 4 Sizes Hollow Core EPS - Etsy
HARD COATING STYROFOAM! Cheap Way To Make Foam Props Strong (Big Halloween Pumpkins) - YouTube