Abstract: A heat conductive material in solid form which is readily excoriated whereby it can be applied by rubbing on the surface to which it is to be applied is formed, in the preferred form, by mixing finely divided heat conducting solids in a waxy material. That material is formed of waxes, or certain fats, and is solid in the range of normal room temperatures. In preferred form, it becomes molten at temperatures in that range just above normal room temperature at which heat generating electronic semi-conductor devices often operate.The mixture is applied at normal room temperature in sheet insulator form by rubbing, or at elevated temperature by painting. It is applied to the surfaces to be mated and across which heat is to be conducted whereupon the surfaces are mated with the coating between them.