Abstract: A system is disclosed for impregnating a stack of low permeability core samples with epoxy resin, preferably containing fluorescent dye. The system is particularly suited for preparing core samples from tight gas sands for thin section analysis. The system creates channels through which the epoxy can flow, thereby avoiding the problems of prior methods where uppermost samples in a stack prohibit epoxy flow from reaching lowermost samples in the stack. In the practice of this invention, the core samples are alternately layered with a highly permeable material such as a synthetic material comprised of silica sand bonded with aluminum silica glass. The resulting stack is encapsulated in heat shrink tubing with coarse sand positioned between the outer walls of the stack and the inner walls of the tubing. After the tubing is heat shrunk around the stack, the stack is placed in an overburden coreholder for introduction of epoxy into the core samples under increasing pressure.