Abstract: Process for the production of precision castings with well-defined reproduction of detail and a great accuracy of measurement, by which the pattern to be reproduced is equipped with a drainage apparatus, having at least one duct extending outside the molding box, and the molding material containing phosphate as the bonding agent is poured in the molding box and solidified. After the pattern is removed from the solidified mold, by the introduction of compressed gas, the water of the solidified material is pressed out, and after calcining at a temperature of at least 250.degree. C., the mold is connected to a vacuum line and evacuated. The molten metal mass is then poured into the mold while the vacuum is maintained and solidified.