Polyester resins are primarily used for embedding, coating or encapsulation applications. They repair, consolidate and gap-fill, while also sealing numerous substrates. There are three main types of polyester resin:
- Gel coat: this thixotropic resin does not run when applied to a vertical wall.
- Transparent casting and embedding resin: it is advisable to heat the mould before casting the resin, since the resin contracts by 3 to 5%.
- Opaque casting resin with added filler: due to its low viscosity, this polyester resin is recommended for solid-part casting.
Due to their significant contraction during curing, polyester resins are rarely used in engineering applications. A polyurethane resin would be preferable for this type of application.
Some polyester resins are ideally suited to marine applications.