“Rigidizer” hardener made of an amorphous, synthetic and inorganic silica solution. Usable at high temperatures up to 1200°C. Can be superficially applied to ceramic fiber covers. Unlike more classic covers, the “Rigidizer” penetrate deeply inside the extremely porous fibers’ matrix. The level of tenacity will depend on the concentration of the hardener and on the application method (by brushing, spraying or immersion). These materials are easy and quick to use thanks to their fast drying times.