A series of experiments has been conducted during the past eighteen months with the objective of degerming the accuracy with which precision parts can be duplicated using a castable tooling plastic as a test shape to be reproduced. A precision ground ground 1/4 inch-thick, 90° steel sector of 4'' radius was chosen. The plastics used in the experiments were the die surfacer mixes of the Devon Cooperation and Ren Plastics, Inc. These were selected for use in the test because of their dimensional stability and wear resistance. Ordinary paste type floor wax was used as a mold release. The first series of tests were primarily intended to gain facility in handling this material. After achieving some familiarity with the use of these castable plastics a technique was devised which seemed to hold promise of precision duplication.