Abstract: A process for producing molds, models and tools from hard gypsum and/or cement including applying at least one base layer composed of a binder to a model from which a mold is to be made and which has been provided with an unmolding agent, and pressing onto this base layer a glass fiber reinforced molding composition composed of 95 to 0 weight % .alpha.-calcium sulfate hemihydrate, 0 to 95 weight % cement, 0.5 to 8 weight % glass fibers and 0.5 to 4 weight % suspension agent, with reference to the dry weight, as well as water in a wet-on-wet process and unmolding the resulting laminate after it has set.

Abstract: Fast-setting alpha calcium sulfate hemihydrate made from calcium sulfate dihydrate by hydrothermally recrystallizing calcium sulfate dihydrate to form a mixture containing 95%-99% by weight alpha calcium sulfate hemihydrate and 5 to 1% calcium sulfate dihydrate. The dihydrate in this mixture is then converted to beta calcium sulfate hemihydrate by calcining, except for a remainder of up to 0.5 percent of dihydrate, which remains in the mixture.