This paper presents the principles involved in the transfer of heat and the affect on solvent evaporization in ovens employing high air mass flow. The thermal boundary layer is explained and the development of the forced convection co-efficient and how it affects the rate of heat transfer is shown. A brief explanation of infra-red radiant energy is discussed and equations are included that allow the interchange of radiant energy to the board to be computed. The paper concludes in a discussion of the application of each type of oven in a coating line.