MATERIALS AND MOLDING METHODS 



4-7 



Small inaccessible voids and areas requiring high bulk in small boats are usually filled 

 with a pre-mix of chopped strands and resin. 



Chopped strands mixed with mineral fillers and resins, form molding compounds 

 readily adaptable to matched die moldings (1, 151. The resin, carrying the reinforcement, 

 flows into place during the pressure molding process. These compounds can be used for 

 molding small parts such as deck cleats, arm rests, trim, etc. 



Cloth 



Cloths and tapes are woven from twisted and plied strands of glass filaments. A wide 

 range of weights and weaves are commercially available for special applications. Plain or 

 square weaves, satin weaves and unidirectional weaves are among the available types. 

 Good drape or shaping of some cloth reinforcements is possible but the material must be 

 tailored to obtain proper location and orientation. 



Plain Weave: Represents the simplest and commonest construction in woven cloth and 

 is made in a number of styles. One cloth widely used in boat construction is a plain weave, 

 weighing 10 ounces per square yard, and is commonly designated as boat cloth (6), Fig. 4-8 



Satin Weaves: Employ warp threads that pass over or under three or more fill threads 

 giving high strength and directional properties, Fig. 4-9. Satin weave cloths are used pri- 

 marily in the aircraft industry for obtaining very high strengths. 



Fig. 4-8. Fiberglass Boat Cloth 



Fig. 4-9. Satin Weave, 181 Cloth 



