SMC, or sheet molding compound, is polyester-based fiberglass used in the production of automobiles and other modes of transportation. All fiberglass resins are either polyester-based or epoxy-based.
SMC fiberglass resin is polyester-based and used for repairing SMC on automobiles and other fiberglass products. This product is used in conjunction with fiberglass mat, cloth or tape. It is waterproof and impact-resistant. SMC resin sets in 20 to 30 minutes. Repairs using this product are sandable more quickly than with epoxy-based fiberglass resins. A hardener must be added to SMC resin prior to use. SMC resin can be used to repair both polyester-based and epoxy-based fiberglass products.
Epoxy-based fiberglass resin is thick and is not tacky when cured. After curing, it can be filed, sanded and drilled. This resin is designed to be used with fiberglass mats, cloth or tape. A hardener must be added. Epoxy-based resins have been around much longer than SMC resins. This type of resin can be used to repair items made from epoxy-based fiberglass.
Automobiles made from SMC prior to 2001 had many issues with paint popping, micro-cracking and cratering. SMC polyester-based fiberglass is an improvement over the previous epoxy-based fiberglass composite materials in the automotive industry. Since 2001, more improvements have been made with SMC composite materials and producers are close to an SMC formula that can be used in the production of aircraft.
