About G-10/FR-4|Glass-fiber reinforced epoxy laminate. Extremely strong and stiff for a plastic. FR-4 is the flame-retardant version used for printed circuit boards. G-10 is the base specification without flame retardancy requirements. Machines with carbide tooling because the glass fibers are abrasive and destroy HSS. Creates hazardous fiberglass dust; proper extraction and respiratory protection are mandatory. Used for electrical insulators, structural supports, circuit board substrates, and precision tooling. Compare to
Phenolic Grade XX (cheaper, lower performance) and Carbon Fiber laminate (lighter, stiffer, more expensive).