Check this homemade WB out

[Martinm210]

I get what your saying now and its along the lines of what I was thinking to do. Before I start with micro channels, I am going to try my luck with 1/16". Once I get a feel for the micro milling I will find some smaller taps.

Now, back to thermal conductivity... If copper has a much higher thermal conductivity then water, why do larger amounts of copper do so crappy at pulling heat from a cpu base?

Its because the copper is a solid so the heat must travel through the mass of copper, when water has the fluid speed advantage. At 1.5GPM, the water is moving a lot faster in those tiny block channels (v=q/a) than copper can move it as a solid.

Think about holding a 1 ft piece of copper pipe in your bare hand and heating one end with a torch. It would still take a good 10 seconds or so for the heat to make its way to your hand before you have to let go. Now think about the speed of water in that pipe...its much faster...now think about the tiny cross sectional area in the block at the nozzle inlet...its even higher...

In essence the waters thermal conductivity is increased by its flow rate.

There is more going on there, but that helps me make sence of it a little.