Strictly speaking, the original glass fiber resin was p […]
Strictly speaking, the original glass fiber resin was polyester resin. Formal glass fiber is a composite material composed of glass fiber (similar to glass fiber in insulating materials) and a binder resin. The first resin used is polyester resin, which is the resin you find in vintage cars (classic frigates), vintage surfboards, and even some vintage musical instruments. As materials have evolved and started to be used in more types of products and required different properties, they changed the type of monomers in the resin. It is added for better flexibility of compounding (often vinyl esters), stronger (epoxy other things resins) or cheaper (styrene monomer).
Now what they call glass fiber resin is a mixture of various monomers. Pure polyester or epoxy is better. If you are going to do your own custom blending, you can get polyester fiber, styrene and vinyl ester as pure components and add the required amount. Epoxy resins are usually pure and can be mixed with other additives because epoxy resins are expensive.