Composite materials hand layup

The only specialist use of hardness testing for composite materials is related to the assessment of cure using the Barcol hardness test available as EN 59 [16], The test is frequently used as a low-cost quality check on the cure of laminates such as hand layup CSM materials used in marine and general purpose commercial moldings. Care should be taken to avoid cracking thin laminates. 

A simple definition for a composite is two or more materials, that when combined, will retain their original identities but do interface chemically and physically when subjected to specific conditions of either time, temperature, pressure, or chemical catalyzation. Composites are widely available with different resin systems and reinforcement combinations. They are produced in several physical forms and can be shaped with conventional molding methods as well as a variety of other less conventional methods such as resin transfer molding (RTM), resin injection molding (RIM), structural resin injection molding (SRIM), hand-layup, and autoclave molding(i.e., vacuum bag technique). 

Note the constraints associated with each technique, e.g., filament winding results in non-smooth outer surface pultrusion does not normally result in a quasi-isotropic laminate. For large structures, the relative cost of the filament winding is less than one-fourth that of hand layup and less than one-half that of the best tape laying machine. Use the least expensive form of composite raw materials. 

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