Polyester Stucco For Marble. HOW TO USE: Surfaces must be clean, dry, rough, free of dust and grease. Take out the amount necessary for the application and catalyze it by adding from 1 to 3% of the appropriate hardener, depending upon the environmental temperature and the hardening time you desire to obtain. Mix the two components very well. Workability and application time: about 5 minutes at 20°C. The stucco is sandable after 20-30 minutes.