How does gel coat differ from standard polyester resin?

Gel coat differs from standard polyester resin primarily in its formulation and intended use. One of the primary distinctions is that gel coat typically contains a surfacing agent, which serves to create a smooth, durable finish when applied to composite surfaces. This agent enhances the gel coat's performance, helping it to cure to a glossy sheen that is aesthetically pleasing and functional.

While one might consider that gel coat has no surfacing agent, that is not accurate. In fact, the presence of the surfacing agent in gel coat is what sets it apart, allowing it to provide a protective layer that can withstand UV exposure and environmental challenges more effectively than standard polyester resin. This formulation is specifically designed for the outer layer of composite structures, making it vital for applications in marine, automotive, and architectural contexts.

Factors like color and viscosity can vary between different types of gel coats and resins, but these characteristics are not the primary distinguishing points that define gel coat. Instead, the inclusion or exclusion of surfacing agents is critical to understanding the functional differences between gel coat and standard polyester resin.