Designed experiment testing and pilot production tests were conducted in an effort to identify alternative refractory materials to replace zircon for investment casting shell prime layers. Resultant surface finish quality was evaluated to determine the suitability of candidate refractory materials in prime layer applications. Five prime stucco materials, four fused silica/zircon prime flour blends, four metal alloys, four prime slurry viscosities and four metal pour temperatures were used in this investigation. The results of the evaluation testing confirm that, under appropriate application conditions, acceptable surface quality can be produced without the use of zircon in either the prime layer slurry and/ or prime stucco. Further results show that under some conditions (low prime viscosity in particular) even high zircon containing prime layers can result in an unacceptable surface finish. Application details that result in acceptable finished part surface quality are discussed. The immediate solution to the zircon flour shortage appears to be dilution. The solution for the zircon stucco shortage may be either substitution or dilution. Either zircon stucco or flour reduction requires that process parameters be optimized for the either alternative.