SOLAREZ repair putty is a mixture of clear, non-yellowing, high-strength, fiber-reinforced polyester resin and an amazing solar-activated catalyst. There is no mixing required, just use it right from the tube. It gels in 30 seconds, curing in 3 minutes - but ONLY when exposed to sunlight. The proprietary formula assures that millions of fiberglass fibers are thoroughly wet-out and evenly dispersed in every dose.