The process of melt loss is called dewaxing. After the shell is made, it is generally required to park for a period of time before dewaxing. Park is also a shell during the residual hardener of coating layer to hardening process, with the increase of parking time, shell of wet strength, water resistance and enhanced shell dewaxing there are many methods of the commonly used method of hot water, high pressure steam method and microwave dewaxing method, such as sodium silicate shell due to the widespread application of low melting point paraffin wax stearic acid mold material, so, more application of hot water.