Polyester, Glass-Reinforced Plastic Stucco. For applications with spatula directly upon degreased, sanded plating and glass-reinforced plastic. How To Use: Withdraw the amount required for the application and catalyze it by adding from 1 to 3% of the proper hardener, depending upon environmental temperature and desired hardening time. Mix the two components very well. Workability and application time: about 5 minutes at 20°C. Stucco is sandable after 20-30 minutes.