A method for controlling thermal conductivity between two thermal masses includes thermally contacting a first conduction body with a heat source, thermally contacting a second conduction body with a heat sink, and thermally contacting the second conduction body with the first conduction body by moving the first conduction body between a first position and a second position with a thermal expansion component. The thermal expansion component moves the first conduction body between the first position and the second position at a predetermined temperature and heat is conducted from the heat source to the heat sink through the first and second conduction bodies.