A method for manual casting of polymers, is used for production of a molded part. The production of the molded part comprises providing a mold with a cavity, preparing a liquid polymer according to a recipe, manually casting the liquid polymer into the mold and solidifying the liquid polymer in the mold resulting in the molded part. A system comprises the mold and at least one sensor Wherein the system uses parameter data to calculate the recipe. The system comprises an electronic device and a display, wherein the electronic device controls the display. The display shows during the production of the molded part at least a part of at least one production step of the recipe.