Fiberglass Chopped Strand Mat (CSM) • 13.5oz (1.5oz) • ≈458 gsm • 50" Width

This general-purpose chopped strand mat (CSM) is composed of short E-glass strands randomly distributed and bound into a uniform sheet with a styrene-soluble binder. The binder dissolves in polyester or vinyl ester resins for easy wet-out and strong interlaminar bonding. With an areal weight of 13.5 oz sqyd, (1.5 oz/458 gsm) and a 50 inch (127 cm) width, this mat is ideal for fast laminate build, reducing print-through over fabrics, and creating smooth repair and fairing layers.

Key advantages

• Fast thickness build: Adds bulk efficiently for structural repairs and core bedding.
• Improved interlaminar strength: Random fiber orientation enhances shear properties between fabric plies.
• Print-through reduction: Serves as a veil layer to mask heavy weave patterns for a smoother finish.
• Conformability: Drapes well over radii and complex contours; tears by hand for feathered seams.
• Versatile workflow: Excellent for boat building/repair, mold work, and general industrial laminates.

Typical uses

• Backing gelcoat and cosmetic surfaces to minimize print.
• Boat hull, deck, and transom repairs; stringers and bulkheads.
• Tooling and mold construction between fabric or roving layers.
• Fairing layers and general purpose reinforcement in hand layup/spray-up.

Specifications

• Fiber: E-Glass
• Construction: Random chopped strands with styrene-soluble binder (powder/emulsion)
• Areal weight: 13.5 oz (1.5 oz/458 gsm)
• Width: 50" (127 cm)
• Resin compatibility:Polyester and Vinyl Ester (recommended). Not recommended with epoxy, as the binder does not dissolve and wet-out is difficult.

Processing notes

• Wet out thoroughly with polyester or vinyl ester; dissolving the binder allows full fiber impregnation.
• Use consolidating rollers to remove air and achieve a uniform laminate.
• Tear rather than cut edges when feathering joints to avoid print lines.
• Place CSM between structural fabric plies to maximize interlaminar bond and reduce print-through.

Ordering

• Standard width: 50" (127 cm)
• Sold by: Linear yard – 1 yard = 36" x full width
• Continuous Lengths: Multiple yards ship as one continuous roll whenever possible

Color Disclaimer:Due to individual monitor settings, lighting, and calibration, actual fabric color may vary from what is shown online.

We sell this fabric by the linear yard. You will receive a continuous piece of fabric at the width listed.

For example, if the fabric is 50" wide, a quantity of 1 (linear yard) equals a continuous piece measuring 50" wide × 36" long. A quantity of 5 (linear yards) equals a continuous piece measuring 50" wide × 180" long.