Abstract: A method for making internal passages for use in investment casting processes, especially for gas turbine components such as blades or vanes. The apparatus includes a first mold cavity having grooves formed therein, a second mold cavity having a shape complementary to the final casting design and ceramic cores. Each groove of the first mold cavity has a depth equal to a radius of a certain number of ceramic cores which correspond to cooling channels. The ceramic cores are placed in the first mold cavity and fugitive wax is injected for temporary positioning of the cores. Two fugitive wax segments are formed about the cores. The fugitive segments locate the ceramic cores in the second mold cavity, and wax is injected about the cores and locating segments to form a pattern for investment casting process.