Composite Fabricating Basics Part 1: Fabric Selection

Home
/
Composite Fabricating Basics
/
Composite Fabricating Basics Part 1: Fabric Selection

Step One: Fabric Selection

Types of Fabric Weave Style and Surface Finishing for Resin Type Compatibility

Fabrics are generally considered ”balanced” if the breaking strength is within 15% warp to fill and are best in bias applications on lightweight structures. “Unbalanced” fabrics are excellent when a greater load is required one direction and a lesser load in the perpendicular direction.

Tow	The bundle of individual carbon filaments used to weave carbon fabric. 50k tow means there are 48-50,000 carbon filaments in the tow. Smaller tow i.e. 12k, 6k, 3k and 1k are obtained by dividing the 50k tow into smaller bundles.
Thread Count	The number of threads (tow in carbon and yarn in Aramid) per inch. The first number will be the warp count and the second will be the fill count. Fill: The threads that run the width of the roll or bolt and perpendicular to the warp threads.
Warp	The threads that run the length of the roll or bolt and perpendicular to the fill threads.
Finish	The chemical treatment to fiberglass making it compatible with resin systems, therefore improving the bond between the fiber and the resin. Finishing fiberglass typically decreases the fiber strength by as much as 50%. Both Silane and Volanfinishes are epoxy compatible. Historically, Volan has been considered a softer finish for a more pliable fabric, but recent advances have yielded some excellent soft Silanefinishes.
Thickness	Measured in fractions of an inch. The thicker the fabric the more resin required to fill the weave to obtain a smooth finished part.

Weaves

PLAIN WEAVE

A very simple weave pattern and the most common style. The warp and fill yarns are interlaced over and under each other in alternating fashion. Plain weave provides good stability, porosity and the least yarn slippage for a given yarn count.

2×2 TWILL WEAVETwill weave is more pliable than the plain weave and has better drivability while maintaining more fabric stability than a four or eight harness satin weave. The weave pattern is characterized by a diagonal rib created by one warp yarn floating over at least two filling yarns.

4-HARNESS SATIN WEAVEThe four-harness satin weave is more pliable than the plain weave and is easier to conform to curved surfaces typical in reinforced plastics. In this weave pattern there is a three by one interfacing where a filling yarn floats over three warp yarns and under one.

8 HARNESS SATIN WEAVET

he eight-harness satin is similar to the four-harness satin except that one filling yarn floats over seven warp yarns and under one.This is the most pliable weave of standard fiberglass weaves and is used for forming over curved surfaces.

Commercial Fiberglass-Fabric Weaver

Finishing Cross Reference & Resin Type Compatibility

RESIN COMPATIBILITY	Burlington Industries	Clark Schwebel	J.P Stevens	Uniglass Industries
Epoxy, Polyester	VOLAN A	VOLAN A	VOLAN A	VOLAN A
Epoxy, Polyester	I-550	CS-550	S-550	UM-550
Phenolic, Melamine	I-588	A1100	A1100	A1100
Epoxy, Polyimide	I-589	Z6040	S-920	UM-675
Epoxy	I-399	CS-272A	S-935	UM-702
Epoxy		CS-307		UM-718
Epoxy		CS-344		UM-724
Silicone	112	112		n-pH (neutral pH)

Satin Weave Style For Contoured Parts Fabricating

These styles of fabrics are one of the easiest fabrics to use and it is ideal for laying up cowls, fuselages, ducts and other contoured surfaces with minimal distortions.

The fabric is pliable and can comply with complex contours and spherical shapes. Because of its tight weave style,

satin weaves are typically used as the surface ply for heavier and coarser weaves.

This technique helps reduce fabric print through and requires less gel coat to create a smoother surface.