Abstract: The invention utilizes the adhesive properties which plastic material exhibits while still hot combined with a multi stage molding operation wherein one side of an insert or core located in one side of a mold is coated with molten plastic on a first closing of the mold, the mold is then opened with the plastic still hot to remove the insert or core from the one mold side by virtue of its adherence by the hot plastic to the other mold side, a second charge of plastic is then introduced into the said one mold side and the mold is closed again with the plastic in a molten state to complete the encapsulation of the insert or core.