What issue is polyester resin known for in terms of fiberglass usage?

Polyester resin is particularly known for its susceptibility to osmotic blistering, which is a significant issue when it comes to fiberglass applications. Osmotic blistering occurs when moisture penetrates the laminate and creates blisters beneath the surface. This can happen because polyester resins are permeable to water over time, especially when exposed to a moist environment or in situations where the laminate is submerged in water.

These blisters can compromise the structural integrity and aesthetic appearance of the fiberglass, leading to expensive repairs and maintenance. Manufacturers and builders are often aware of this drawback, prompting them to consider alternative resins or to take specific precautions in the construction process, such as applying barrier coats or selecting materials designed to minimize water permeability.

While weight, cost, and flexibility are important characteristics of materials used in fiberglass constructions, they do not pose the same level of concern regarding long-term durability and performance as osmotic blistering does. Therefore, the issue of osmotic blistering is a crucial factor specifically tied to the limitations of polyester resin in fiberglass applications.