Abstract: A method of coating a core sample in which a distillate such as petroleum jelly is applied to the exterior surface of the sample. A cylindrical mold is partially filled with a plastic mixture of hardenable epoxy resin and hardener therefor, and one end of the core sample is slowly inserted into the mold under a pressure which preferably is not more than about 50 pounds per square inch. In some cases the inserted end of the sample is pre-coated with the plastic mixture. As the insertion of the sample is continued, the mixture flows up the side of the sample and covers the opposite end. The coating is cured by maintaining it in the mold at room temperature for a period of time sufficient to enable the resin to set up and then by holding it at an elevated temperature for at least about eight hours. Upon the removal of the coated sample from the mold, the ends are cut off to expose the sample material.