Best metal for heatsinking?

bmstrong

Flashlight Enthusiast
Joined
Jul 23, 2002
Messages
1,334
Silly question? If cost were no object and you had your pick of all the metals out there?

What metal heatsinks the best? I'm curious.
 
right on!

silver is the best conductor too. years ago I plated bus bars for a nuclear power station. silver was the choice of metal over gold.
 
Wonder if anyone here has used silver oxide paste like artic silver in thick 1/4" layer around kiy sink or between reflector and head?


Silver for everything, it's the best electrical and thermal conductor (metalic) and the oxide is even better as a conductor.
 
#1 Silver, #3 Copper, #3 Aluminum, in heat conductivity, and electrical conductivity
 
An Al heatsink would be good with an Al light where there is good thermal contact between the heatsink and body of flashlight. A nice copper heatsink meeting the aluminum body of a flashlight might tend to cause the heat to load up in the heatsink due to the lower thermal conductivity of the al body. Am I correct here, mostly?. I guess that might depend on the grade of aluminum, some al grades conducting heat better than others.

Bill
 
An Al heatsink would be good with an Al light where there is good thermal contact between the heatsink and body of flashlight. A nice copper heatsink meeting the aluminum body of a flashlight might tend to cause the heat to load up in the heatsink due to the lower thermal conductivity of the al body. Am I correct here, mostly?. I guess that might depend on the grade of aluminum, some al grades conducting heat better than others.

Bill
I don't know if a copper-aluminum junction has necessarily higher thermal resistance than an aluminum-aluminum junction (certainly, an all aluminum light that was milled from one piece of aluminum with no "gap" would have lower thermal resistance), but even if it does, another issue that should be considered is heat capacity:

Copper is a higher density metal, thus in a given volume, a heatsink of copper will be able to "soak up" a lot more heat before rising in temperature. In small lights without a lot of surface area to dissipate heat, heat capacity can be extremely significant -- for example, comapring my LF2 and L0D-CE, both of which dissipate similar amounts of power, and have simialr surface areas, the LF2 tends to get hotter because it uses thinner material in the head (more room taken up with circuit boards).

So even if the same amount of heat or slightly more is trapped inside a light with a copper heatsink as with an aluminum heatsink, the temperature will not rise as much.
 
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