Peningkatan kekerasan RTV silicone rubber untuk pembuatan cetakan (rubber mold) pada proses spin casting

Abstract

In general, Small and Medium Enterprise (SME) in the manufacture of pewter craft product that uses spin casting process still use vulcanized silicon rubber molds which require high production cost. SME intends to reduce production cost without decreasing the quality of the product significantly. There is another alternative beside using the vulcanized silicon rubber molds, which is by using room temperature vulcanized (RTV), as the rubber molds has lower material cost, but the hardness mechanical characteristics of RTV rubber is lower than the vulcanized silicon rubber. So that the rubber mold is easier to be deformed and changed the shape of the product itself. This study aims to increase the hardness of the RTV rubber molding with the addition of talc lioning powder. The process of improving the hardness of the rubber mold is initiated by the addition of talc into RTV gradually and hardener is added to speed up drying. The research process was conducted in the jewelry laboratory of Balai Besar Kerajinan dan Batik Yogyakarta. From the research conducted, it is found that the most optimal ratio of material mixture variation is 50: 1: 40 (50 grams of RTV, 1 gram of hardener, and 40 grams of talc).