low speed rotational molding of plastic objects at about ambient temperatures from a liquid thermosetting plastic material distributed in a mold substantially under gravitational force ; the selected thermosetting plastic is placed as a distributable liquid in a mold having a volume much larger than the volume of the liquid polymer and slowly rotated about two axes at or about room temperature ; urethane polymers to which a quantity of diamine curing agent has been added prior to the introduction of the flowable plastic into the rotatable mold are typical thermosetting materials ; useful objects or shapes having thin , relatively uniform walls are produced by the disclosed process ; repetition of molding steps allows the build up of same or different layers which may have interposed therebetween , lightening , stiffening , and / or strengthening members ; precoating of a mold with a variety of coatings which release , interact , or decorate the thermoset resin surface is also disclosed .