Isophthalic Gelcoat (Gray, Tooling)

This gray isophthalic tooling gelcoat is specifically formulated for the production of high-quality FRP molds. Based on a modified isophthalic resin with enhanced thermal stability, it delivers a hard, dimensionally stable mold surface that resists distortion during extended production runs. The mid-gray color provides an ideal neutral background for visual quality inspection of molded parts, making surface defects such as pinholes, voids, and fiber print-through clearly visible. Pre-pigmented to a uniform medium gray, the gelcoat exhibits excellent coverage and a smooth surface finish upon demolding. Cobalt pre-accelerated, it cures with MEKP at 1–1.5% by weight. Extended gel time of 35–60 minutes at 20°C with 1.5% MEKP provides ample time for thorough spray application to the pattern or plug surface. Barcol hardness after full cure and post-cure is typically 50–55, providing the surface hardness needed to withstand repeated demolding cycles and mold cleaning. The isophthalic base offers improved resistance to the solvent content of resins used in the laminate, which can cause a softer orthophthalic gelcoat to swell or suffer surface degradation over time. Compatible with all polyester and vinyl ester tooling laminate systems.