... ) Materials: special grade gypsum powder, Methyl Cellulose (HPMC), retarder 2) Joint comp Features: 1) Materials: special grade gypsum powder, Methyl Cellulose ... (HPMC), retarder 2) Joint compound powder provides the performances of strong binding force, high ... of cornice c) Concreting after 1 hour Packing: 20kg/bag Joint Compound Powder