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- Aug 18, 2018
- Messages
- 3,190
@saito197: Just to make sure: Everything I wrote above as a tech tip, starting from the hammering of, including the cleaning with alcohol/water (even if it is distilled) of, to the smearing of useless thermal compound all over electronics was wrong. 
You really shouldn't do any of that.
In the case of thermal paste (and to save my honor), I can add this (this time honestly meant) explanation to the "applying extra is gonna do more harm than help" argument:
Thermal compound is meant to bridge the gap between the chip package's and the heat sink/heat pipe's surfaces. Air is an excellent heat insulator. (Just imagine the difference between standing naked in a room with 4°C/39.2°F cold air and swimming in a pool with 4°C/39.2°F cold water (a much better heat conductor). In one case you can survive up to a few hour in the other you won't make it past a few minutes.) Direct contact between materials is a good way to transfer heat, but even in the case of die encasing/chip packaging and the metallic surface of heat sinks/pipes/spreaders, there are irregularities on the surface (just imagine a veeeery small dent, a slight bend or a few mounds) and gaps of air form in between them. The heat transfer is sub optimal there. Heat compound will displace those air pockets and fill their space instead, if you add a drip on one surface and press them together.
As its heat conductibility is superior to air, that's a good thing, but in most cases its conductibility is still worse than the material of the heat sink. Even in cases it is better, it still adds another layer of material, that has to be overcome. Therefore -> The thinner that layer is, the better. Adding too much compound widens the layers size, or even worse, if badly applied might even entrap and embed bubbles of air, which in turn might even be thicker, than the initial thermal gaps without paste. (Though even in those cases applying compound is still better, than not doing it at all.)
Being stingy is a good thing, but don't be too stingy or it won't be enough to cover the whole contact surface. So adding a little bit more, than you think is needed to cover everything in between is fine.
You really shouldn't do any of that.In the case of thermal paste (and to save my honor), I can add this (this time honestly meant) explanation to the "applying extra is gonna do more harm than help" argument:
Thermal compound is meant to bridge the gap between the chip package's and the heat sink/heat pipe's surfaces. Air is an excellent heat insulator. (Just imagine the difference between standing naked in a room with 4°C/39.2°F cold air and swimming in a pool with 4°C/39.2°F cold water (a much better heat conductor). In one case you can survive up to a few hour in the other you won't make it past a few minutes.) Direct contact between materials is a good way to transfer heat, but even in the case of die encasing/chip packaging and the metallic surface of heat sinks/pipes/spreaders, there are irregularities on the surface (just imagine a veeeery small dent, a slight bend or a few mounds) and gaps of air form in between them. The heat transfer is sub optimal there. Heat compound will displace those air pockets and fill their space instead, if you add a drip on one surface and press them together.
As its heat conductibility is superior to air, that's a good thing, but in most cases its conductibility is still worse than the material of the heat sink. Even in cases it is better, it still adds another layer of material, that has to be overcome. Therefore -> The thinner that layer is, the better. Adding too much compound widens the layers size, or even worse, if badly applied might even entrap and embed bubbles of air, which in turn might even be thicker, than the initial thermal gaps without paste. (Though even in those cases applying compound is still better, than not doing it at all.)
Being stingy is a good thing, but don't be too stingy or it won't be enough to cover the whole contact surface. So adding a little bit more, than you think is needed to cover everything in between is fine.
