Using epoxy to mount a sample before processing is an effective way to provide additional support to samples during subsequent grinding and polishing and is especially important with delicate and porous samples. However, to get this important internal support, the sample must be penetrated as fully as possible. Vacuum impregnation has been widely recognized as an effective way to improve penetration of the epoxy resin by removing air entrapped in the pores of the sample, enhancing capillary action and reducing the barriers for the epoxy to move into the specimen pores. Pouring epoxy under vacuum is a proven method of reducing this resistance and increasing epoxy penetration.