G10:
Machining with a computerized numerical cutter (CNC) is the most accurate form of fin shaping besides pre-preg high-compression moulding. CNC G10 is the preferred manufacturing method for smaller fins as the strength and toughness of G10 provides significant advantages. Because no moulds are needed, each size can have individual outlines, allowing for greater freedom in designing a fin’s plan shape. This is a key criteria for fins with a high degree of curvature along the leading and trailing edges: wave fins, freestyle fins and cross over fins.
Compared to polyester, G10 is a far superior material with greater strength and toughness. A G10 fin also provides a quicker flex response and allows the designer to use thinner sections for the same desired flex. The result is a faster fin with more responsiveness.
Pre-peg:
The blades are produced from symmetrical, CNC machined aluminium moulds whose surfaces are heated to 280oC. Fibres pre-impregnated with epoxy resin are laid out in the mould and compressed under hydraulically applied pressure. The use of prepreg fibres reduces micro-voids in the composite for the optimized strength, fatigue resistance and flex response. Prepreg technology also allows for an accurate cut and positioning of each individual layer which in turn allows designers to achieve a very specific flex pattern without compromising the shape of the fin. Prepreg is the ultimate and most accurate construction for fins over 40cm where any other method would result in blade that is too thick, too thin, or too soft.
The materials used are a combination of carbon weave, biaxial carbon, glass weave and 3 dimensional GTX fibres (Glass tri-axial). The GTX fibre’s thick compressible nature allows the mould surfaces to close fully and ensure a blade whose shape is true to the original. Each prepreg fin is individually custom finished by hand, with a minimal paint and gelcoat finish to meet tighter tolerances.
Sacado de la web de Drake fins. http://www.drake-windsurfing.com
Breve resumen en castellano:
El G10 consiste en cortar y "moldear" a base de lija unas planchas previamente fabricadas con fibras y resina prensadas a alta presión. Esto permite trabajar mucho la forma por lo que se usa para aletas de wave, freestyle y cross over (polivalentes). Respecto al pliester, el G10 és más rígido y resistente, dando una respuesta a la flexión más rápida y permite al diseñador aplicar diferentes grosores en diferentes zonas para conseguir respuestas rápidas según su forma y grosor.
El pre-peg (que no quiere decir más que pre-impregnado con resina) es una técnica en la que en lugar de hacer una plancha a presión y luego darle forma, se usan moldes que ya tiene la forma y luego se meten los materiales y se da presión. Eso permite aplicar diferentes materiales en diferentes zonas (incluso algunos tridimensionales) para conseguir diferentes flexiones y propiedades. Finalemente se le da un acabado a mano y una cobertura de gelcoat para protegerlo. Se usa para aletas grandes pues si se usase la otra técnica tendrían que ser demasiado gruesas.