Polyester Resins

Epoxy resin provides better adhesion, moisture resistance, and flexibility compared to polyester resin. While polyester is more economical and widely used in mass production, epoxy is preferred for high-performance applications, repairs, and situations requiring a strong bond.

Polyester resin is widely used for building and repairing fiberglass boats. It is ideal for laminating fiberglass cloth, molding parts, and creating gelcoat finishes. It’s cost-effective and works well for general-purpose repairs.

No, polyester resin does not adhere well to cured epoxy. However, epoxy can be applied over cured polyester if the surface is properly prepared and sanded.

No, you should not use polyester resin on EPS foam (expanded polystyrene). Polyester resin contains styrene, a solvent that dissolves EPS foam on contact. This reaction will ruin your foam core and release harmful fumes. If you're working with EPS foam—for example, in surfboard shaping or foam core laminates—you should instead use epoxy resin, which is chemically compatible and safe for EPS.

It depends on the surface area, fabric weight, and number of layers. As a rule of thumb, 1 gallon covers about 12–15 square feet with 3 layers of fiberglass cloth. For precise measurements, use our Epoxy Calculator — it works for polyester too with similar coverage rates.

Yes, polyester resin can be tinted using compatible pigments. This is often done to match gelcoat colors or create custom finishes.

Polyester resin cures in about 20–30 minutes at room temperature when mixed with MEKP (methyl ethyl ketone peroxide) catalyst. Cure time can vary with temperature and catalyst ratio.