Rebound™ 25 is an easy-to-use platinum-cure silicone rubber which self-thickens for making brush-on molds of almost any model. Mixed 1A:1B by volume (no scale necessary), Rebound™ rubber can be applied with a brush or spatula to vertical surfaces without sagging and will cure with negligible shrinkage to a flexible rubber. Features: Rebound™ 25 is soft, flexible and is good for making molds of models with deep undercuts. Depending on model configuration, Rebound™ 25 can be inverted as a glove molds. Rebound™ 40 is harder and less flexible. These products are compatible. For example, you can apply two coats of Rebound™ 25 and back it up with two coats of Rebound™ 40. Advantages Over Urethane Brush-On® Rubber: Rebound™ will not stick to most surfaces, so surface preparation is minimal. Two liquids that mix easily together. Stands up better to production casting of resins and low temperature melt metal alloys. Has a long library life. 4 thin layers are all that is necessary to make a flexible, strong and durable production mold for casting wax, gypsum, concrete or resins (urethane, polyester, etc.). And because Rebound™ is a platinum silicone, it will last for many years in your mold library. Applications include reproducing sculpture, architectural restoration, making candle molds, casting pewter, etc. Note: These products will not work with modeling clays containing sulfur under any circumstances.