What is a “thermoset” resin?
Resins used in the panel industry come in two types, thermoset, and thermoplastic. Below is a very unscientific, but understandable explanation of the difference. Thermoset resins (polyester) are liquids that react with a catalyst to form a solid, and cannot be returned to their liquid state. A good comparison is a boiled egg, it starts liquid, heat is applied, and it forms a solid that cannot be made liquid again without destroying it. Thermoplastics resins (PVC) are also liquids that become solids. But unlike thermoset resins, thermoplastics are softened by application of heat or other catalysts. Thermoplastics can be heated, reshaped, heated, and reshaped over and over. A good comparison is JELLO gelatine. It starts liquid, solidifies as it cools, then melts when heated, hardens again when cools.
