I got into a discussion about heat sink materials and was beaten up for suggesting that Aluminum is better than Copper because it will transfer the heat away from itself much faster than copper. Copper has about half the specific heat and about twice the thermal conductivity over Aluminum. Am I incorrect in the notion that the specific heat not the thermal conductivity will dominate the calculation of heat transfer to a gas like air from a metal fin? I took thermo about 30 years ago and didn't really like it much or make a stellar showing. However, I recall that the specific heat is very important when condidering the flux of heat. I also keep thinking about how fast Al will cool down compared to Cu. ---------------------------- May your world be linear, Gaussian, and steady state.