Abstract: A method and apparatus are provided for strengthening a portion of a blow molded bottle. The method includes directing a jet of cooled air at a preform before it is molded, causing the wall thickness in the cooled area to remain thicker after molding to strengthen that area of the blow molded article. The apparatus includes a blow molding machine that is provided with a nozzle positioned to direct the cooled jet of air towards the preform. The nozzle is mounted in a standby station that is in between the existing heating station and blow molding station. In one embodiment, the cooled jet of air is directed at a location just below the neck of the preform to create a ring of increased thickness in the shoulder of the blow molded bottle, adding strength to the shoulder of the bottle. A conventional blow molding machine may be modified to rotate and cool the preform in the standby station.