West System Biaxial E-Glass Fabric with Mat – 22 oz., 50" x 20 yd.

West System Biaxial E-Glass Fabric with Mat – 22 oz., 50" x 20 yd.

A high-performance combination fabric that pairs 17 oz. biaxial E-glass with a 0.75 oz./sq. ft. chopped strand mat (CSM) backing, delivering approximately 22 oz./sq. yd. total fabric weight. The biaxial layers are oriented at ±45° and held together with light stitching, while the mat backing bonds directly to the substrate for improved adhesion and interlaminar strength — all in a single-pass layup.

At 50" wide and 20 yards long, this roll is suited for production builds, major structural repairs, and any application where both directional reinforcement and surface bonding are required simultaneously.

Key Features

• 17 oz. biaxial E-glass at ±45° orientation for balanced multi-directional tensile strength
• 0.75 oz./sq. ft. chopped strand mat backing for improved substrate adhesion and interlaminar bonding
• ~22 oz./sq. yd. combined weight for a single-pass structural laminate
• Non-woven, non-crimped biaxial fibers reduce print-through and maximize stiffness
• Light stitching holds layers in alignment without compromising wet-out
• 50" width accommodates wide hull panels, deck sections, and large structural components
• 20-yard roll length suits production runs and multi-zone repair projects

How It Differs from Plain Biaxial Fabric

The mat backing eliminates the need to apply a separate CSM layer before the biaxial cloth, saving time and reducing material handling in multi-layer schedules. It also improves adhesion to existing fiberglass surfaces, making it particularly effective for repair work where bonding to an aged substrate is critical.

Common Applications

• Hull skin lamination requiring both structural stiffness and strong substrate adhesion
• Deck and cockpit reinforcement over existing fiberglass
• Bulkhead tabbing and stringer reinforcement in production builds
• Repair layups over aged or oxidized fiberglass where interlaminar bonding is a priority
• High-load structural zones requiring multi-directional strength in a single fabric layer

Recommended Epoxy Systems

• West System C105A Epoxy Resin – 946 ml — Low-viscosity laminating resin for thorough wet-out
• West System C105B Epoxy Resin – 3.74 L — Larger format for extended lamination schedules
• West System C205 Hardener – 814 ml — Standard cure hardener for most laminating conditions
• West System C209SB Extra Slow Hardener – 1.24 L — Extended pot life for large layups in warm conditions

Related Fabrics

• West System Biaxial E-Glass Fabric – 17 oz., 50" x 20 yd. — Plain biaxial without mat backing, for clean laminate schedules
• West System 733W Fiberglass Reinforcing Tape – 6" x 10' (2-Pack) — Structural tape for seams, corners, and tabbing

Parts Desk Insights

Best Use Cases: This combo fabric is the right choice when a repair or build requires both structural reinforcement and strong adhesion to an existing substrate in a single step. It’s especially effective for repair work over aged fiberglass hulls and decks, where a plain biaxial cloth may not bond as reliably without a separate mat layer. For new builds, it simplifies multi-layer schedules by combining two fabric functions into one, reducing layup time and the risk of misalignment between separate layers.

Tip: The mat side should face the substrate. Wet out the mat layer first to ensure full saturation before the biaxial fibers are pressed into the laminate. Use a consolidating roller to remove air pockets and ensure intimate contact between the mat and the substrate surface.