MATERIALS AND MOLDING METHODS 



4-19 



excess resin prior to applying positive pressure. Fig. 4-20 illustrates a mold assembly 

 inside a large autoclave. 



The hull size that can be made by this molding method is only limited by the size and 

 initial cost of the necessary equipment. 



I I # 



Fig. 4-18. Rubber blanket in position 

 over fiberglass lay up (Courtesy Universal 

 Molded Products Corporation! 



Fig. 4-19. Molding of 15' hull by pressure 

 bag method ('Courtesy Winner Manufacturing 

 Company) 



Matched Die Molding 



Matched die molding using both a male 

 and female die combined as shown in Fig. 

 4-21, applies both pressure up to 170 PSI 

 (8) and heat to the laminate. In most 

 operations, mechanical stops are used to 

 control the applied pressure and laminate 

 thickness. 



It has been demonstrated that the use of 

 heated, matched metal dies produces fiber- 

 glass boats on a rapid molding cycle (8, 12). 

 At present, matched die molds have been 

 limited in use to hulls of approximately 17 

 feet in length due to the high cost of the 

 initial equipment requiring quantity produc- 

 tion for amortization. 



Sprayed Reinforcement and Resin 



Fig. 4-2 0. Mold assembly inside of 

 autoclave (Courtesy Universal Molded Products 

 Corporation) 



A recently developed production tool, that has caused interest in the boat industry and 

 could possibly be used in all molding methods to increase production, is a special spray gun, 



