The white polystyrene rigid foam is often used in architectural model making because attractive basic planning models which do not require any further colouring work can be produced quickly by employing a hot wire cutter.
Finding this white foam in a density appropriate for our purposes has become very difficult because foamed polystyrene is almost exclusively produced as a dyed material for various insulation uses.
Polystyrene rigid foam is free of HBCD (Hexabromcyclododecane).