High impact polystyrene. Cellulose acetate butyrate is used for its good weatherability and scratch resistance. Wall thickness is constant making variations difficult to control. Fine detailling and textures are easy to achieve. Very large and flat areas are quite difficult to mold.
Part are relatively stress free given the lack of pressure in the process during the molding cycle.
In general, the process is labour and material intensive, especially if multiple parts are molded in one cavity and have to be separared. Some break through technological developments in recent years have increased rotational molding's accessibility and effectiveness. For products such as boats, the foam in some instances provides permanent buoyancy. For rotormolding, HDPE PCR is blended with virgin resin with content ranging from 10 to 25 percent. The fluoropolymer coating allows the polyolefin melt to flow more uniformly, which can significantly reduce pin holes in the surface of molded parts.