... are several broad categories, each with numerous variations. The most common are known as polyester, vinyl ester, epoxy, phenolic, polyimide, ... the product is greatly dependent on this ratio. Typically, most common polymer-based composite materials, including fiberglass, carbon fiber, and ... to 11 g/cm³ (same density as lead). The most common name for this type of material is High Gravity Compound (HGC ...