Description
OptiKast is a coarse-grained kaolin used primarily in ceramic casting applications. It has a very fast cast and exceptional deflocculation characteristics. As such, OptiKast is preferred in pressure casting systems.
As Velvacast kaolin is no longer available, this is the recommended substitute. One concern with Velvacast was its dark fired color (compared to other common plastic kaolins). OptiKast has higher iron and TiO2 contents, which could impact translucency in porcelains. This means that you may need to fire tests and adjust other materials in the recipe if needed. In October 2011, DigitalFire carried out fired shrinkage, porosity, dry performance and plasticity comparison tests between these two materials and the end results show that they do appear very similar; however, OptiKast is a little more plastic and does not appear to fire darker at cone 8 and 10.
