Ding All Polyester Sanding Resin with Catalyst - Smooth and Non-Tacky Product for Surfboard Repairs - 8 ozTHE ORIGINAL POLYESTER SANDING RESIN: Ding All Polyester Resin contains Silmar brand 250A Polyester Sanding Resin, which is the undisputed, highest quality resin available to the industry. Sanding Resin is typically used for surfboard hot coats and is widely popular for use with dings repairs CURES WITH A CATALYST: Each size of our Ding All Sanding resin comes with liquid catalyst to make it cure. Average Cure time is: Gel 6 to 10 minutes, hard in 45