Cast iron makes a good radiator, it was used for many years in heating buildings, and many small engines were at one time cast iron, with the cooling fins built in. But aluminum is both a better conductor and better radiator than iron.
I disagree. Iron is a terrible radiator but it was used for heating for just that reason. I'll explain.
Think about the heat source, large boilers producing hot steam. Imagine using an alumininum radiator. The boiler produces large amounts of steam (and heat) and the aluminum radiator dumps the heat almost immediatly into the room. Oops, that's 212 degrees F and hotter. Pretty toasty room.
Iron was better to use with steam heating. Iron heats up slowly and releases the heat slowly. Very ineffecient heat transfer but very effectively slow room heating.
I'm sure you know more about engines than I do but I do know that aluminum engines give off more heat than iron block engines when you stand next to them. Aluminum engines release heat fast! So I'll grant you that aluminum releases heat better than iron.
I'll have to trust you about brake rotor burns. (LOL!). However, I'll remind you that iron brake rotors aren't used in high performance because iron holds onto heat too long. (This reduces braking effectiveness).
You'll notice the aluminum pan is radiating much better than the cast iron. I mentioned that I think this has something to do with the density of a metal, more specifically, I think that the more dense a material is the more capacity it has to hold heat.
But copper is more dense than iron. By your reasoning iron should make a more effective heatsink than copper.
My proposition is that Copper relies more on conduction, air moving over the heatsink gaining heat energy from physically touching the surface, while Aluminum looses most of it's heat to radiation
I disagree. I believe all CPU heatsinks give off nearly all their heat due to conduction (moving air) and that convection and radiation are small components.
I further believe that heatsink effectiveness is all about airflow and surface area.
How do we prove/disprove our assertions, yours and mine?
<b>56K, slow and steady does not win the race on internet!</b><P ID="edit"><FONT SIZE=-1><EM>Edited by phsstpok on 06/17/03 03:14 AM.</EM></FONT></P>