High Strength High Temperature Fiberglass CFF™ (Continuous Filament Fabrication) Spools. High Strength, High Temperature (HSHT) Fiberglass is a material uniquely designed for users who need strong parts in higher temperature environments (over 105°C, with a heat deflection point of 140°C). This capability is critical for the automotive and aerospace industries where load bearing parts are continually expected to withstand higher temperatures. What is high strength high temperature fiberglass? Extremely thin strands of glass bundled together into a fiber. Fiberglass is traditionally used in composites for boat, automobile, and aircraft manufacture. How strong is high strength high temperature fiberglass? HSHT fiberglass has a flexural strength of 420 MPa (71 ksi) and a tensile strength of 600 MPa (87 ksi).