Abstract: An improvement in the method of operating a molding apparatus as well as an improved apparatus for use in molding plastic and other materials is provided. The inner mold surfaces of the apparatus are flooded, during operation, with a dehumidified gas such as dry air to minimize condensation of moisture onto these surfaces. The dry air is supplied to a chamber surrounding one half of the mold and through channels in the mold onto the molding surfaces. This dry air forms a field in the area of the mold surfaces to keep out the normally moist ambient air. The field is exhausted through a chamber surrounding the other mold half and recirculated to the supply source where it is regenerated and returned to the first chamber. In this way, a continuous concentration of dry air is maintained in contact with the mold surfaces. One or more dry air curtains are established around the dry air field to prohibit moist air from entering the field.