WARP
The yarns running lengthwise and parallel to the selvage in a woven fabric.

WARPAGE
Dimensional distortion in a composite part.

WATER ABSORPTION
Ratio of weight of water absorbed by a material to the weight of dry material. Also called moisture content.

WATER JET
A high-pressure stream of water used for cutting organic composites.

WAX
A mold release agent.

WEAVE
The particular manner in which a fabric is formed by interlacing yarns, and usually assigned a style number.

WEFT
The yarns running perpendicular to the warp in a woven fabric; also called "woof".

WET FLEXURAL STRENGTH (WFS)
The flexural strength after water immersion; usually after boiling the test specimen for two hours in water.

WET LAY-UP
The reinforced plastic which has liquid resin applied at the reinforcement is laid up. The opposite of "dry layup", "prepreg".

WET-THRU
Where the resin flows between the glass bundles (in the case of mat or cut rovings) of flows through the interstices of the woven roving or fabric.

WET WINDING
A type of filament winding in which the fiber strand is impregnated with resin immediately before it contacts the mandrel.

WET-OUT
The condition of an impregnated roving or yarn wherein substantially all voids between the sized strands and filaments are filled with resin.

WET-OUT RATE
The time required for a plastic to fill the interstices of a reinforcement material and wet the surface of the reinforcement fibers; usually determined by optical or light transmission means.

WETTING AGENT
A surface-active agent that promotes wetting by decreasing the cohesion within a liquid.

WET STRENGTH
The strength of paper when saturated with water, especially used in discussions of processes whereby the strength of paper is increased by the addition, in manufacture, or plastic resins; the strength of an adhesive joint determined immediately after removal from a liquid in which it has been immersed under specified conditions of time, temperature and pressure.

WHISKER
A short, single crystal fiber or filament. Whisker diameters range from 1 to 25 microns, with aspect ratios between 100 and 15,000.

WIND ANGLE
The measure in degrees between the direction parallel to the filaments and an established reference point.

WINDING PATTERN
The regularly recurring pattern of the filament winding after a certain number of mandrel revolutions.

WORK LIFE
The period during which a compound, after mixing with a catalyst, solvent, or other compounding ingredient, remains suitable for its intended use.

WOVEN ROVING
A heavy glass fiber fabric made by the weaving of roving.

WOVEN ROVING FABRIC
Heavy fabrics woven from continuous filament in roving form. They drape well, are quickly impregnated, and intermediate in price between mats and yarn cloths.

WOVEN TAPE
Tape of various thicknesses woven from continuous filament yarns.

WRINKLE
An imperfection in the surface of a laminate that looks like a crease in one of the outer layers; it occurs in a vacuum bag molding due to improper placement of the bag.

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Glossary Section (W) Last Updated: 4/27/99 10:17 AM

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