Automotive fiberglass resin requires fiberglass mesh fabric and a catalyst in order to be used. Fiberglass resin and mesh can be used to patch holes in automotive body panels and maintain the required rigidity for a body panel. You can also use fiberglass mesh and resin to create door panels, speaker enclosures and inner panels. Use of this product is fairly easy and full instructions will be found on the packaging for both the mesh fabric and the catalyst. Once mixed application and shaping needs to be completed within about 30 minutes because rigidity will start to set in during that time. Full hardness and curing will occur, in most room temperature and above environments in about two to three hours. More time will be needed in colder environments.