# Best metal for heatsinking?



## bmstrong (Nov 13, 2007)

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.


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## tvodrd (Nov 13, 2007)

Silver, with copper not far behind.

Larry


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## cy (Nov 14, 2007)

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.


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## 65535 (Nov 14, 2007)

Silver for everything, it's the best electrical and thermal conductor (metalic) and the oxide is even better as a conductor.


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## jimjones3630 (Nov 16, 2007)

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?




65535 said:


> Silver for everything, it's the best electrical and thermal conductor (metalic) and the oxide is even better as a conductor.


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## mzzj (Nov 17, 2007)

In weight-limited applications aluminium is better than silver/copper.

Btw. Heatpipes conduct heat wayyyyy better than any metal.


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## chocho (Nov 17, 2007)

bmstrong said:


> 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.



Data (1st column)


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## yellow (Nov 18, 2007)

didnt know there is THIS difference between Alum and copper
:thinking:


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## Anglepoise (Nov 18, 2007)

Obviously not a metal, but Diamond is meant to be pretty good.


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## jugg2 (Nov 18, 2007)

#1 Silver, #3 Copper, #3 Aluminum, in heat conductivity, and electrical conductivity


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## Bullzeyebill (Nov 18, 2007)

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


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## 2xTrinity (Nov 18, 2007)

Bullzeyebill said:


> 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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## Illum (Nov 18, 2007)

Anglepoise said:


> Obviously not a metal, but Diamond is meant to be pretty good.



if you want to go that far...sapphire lens does a pretty good job too...gizmo made a recoil model using it before


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