Often referred to as plaster of Paris or soft plaster, USG® No. 1 moulding plaster is used to create waste molds or temporary patterns where surface hardness and strength are not crucial. USG® No. 1 moulding plaster offers a controlled set that provides uniform workability, has a fine grain making it ideal for producing sharp detail when used neat for cast work. It complies with ASTM C28, sets in 27-37 minutes after mixing.