Rapid freeze prototyping is a solid freeform fabrication method that uses water freezing into ice as the build material. Each layer of geometry is deposited and allowed to freeze before the next layer is added in order to additively create a three-dimensional ice part. A sacrificial support material is needed for the fabrication of complex ice parts. Identifying a suitable support material and understanding the interaction between the build and support materials is the motivation behind this study. A temperature prediction model and a concentration prediction model are presented. Experimental results have been obtained to validate these models.