Abstract: A female mold for plastic sanitaryware manufacture has an open top to promote improved air escape from the mold as resinous backing resin fills the mold in order to reduce the number of gas inclusions within the backing material after it is cured. The female mold also provides thermal insulation for the curing backing material to permit better curing and to reduce the potential for delamination in the finished product. A production fixture is equipped with a gas impermeable lid for selective contact with the female mold, after the air has been expelled from the mold, in order to control undesirable styrene emissions.