Abstract: A vessel for duplicating dental models has at least two mold halves which can be clamped together. The mold halves have elements for mutually centering and for securing the model to be duplicated, for example, a tooth stump or the like. The vessel further includes an intake funnel each for pouring in liquid silicone and refractory casting material. A foil insert is provided in the plane of separation of the two mold halves when the vessel is closed. The foil insert has a thickness which corresponds in size to the setting expansion of the refractory casting material. The model to be duplicated is located in the center axis of the vessel and extends approximately by half its length through the foil insert and is held in position by the foil insert.