I’ve installed heat sinks for my ESC before.
What I was talking about was Heat displacement for my battery in my Pelican case.
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You’re using the right numbers but think about the thickness. Even if Al oxide has thermal conductivity ten times lower this is only for 0.5 mil or so and then it’s back to Al.
I found 30W/m-K thermal conductivity for Al2O3 (alumina) and 205W/m-K for pure Al. Doesn’t matter though.
For 0.5 mil thickness over a 10cm x 10cm patch you get a 0.0003°C temp rise at 50W with raw Al.
For the same thickness using alumina you get a 0.002°C temp rise.
For layers this thin it just doesn’t matter, even with anodizing being a very thermally-insulating ceramic. 
The calculator: https://thermtest.com/thermal-resources/thermal-resistance-in-series-calculator
Lol sorry I know you can build!
Didn’t mean to imply anything
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No need to be sorry.
Text is hard to read emotions lol.
I just wanna keep my build running cool.
I’m a big guy and my hills are real.
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We seem to be heading in the same direction. 
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I’ll pm you some cad pics in a few.
Also…what about using copper? I know it is almost twice the thermal conductivity of aluminum. Is there any benefit to use copper in certain places?
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at least double the cost plus it corrodes @surfnacho
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You hit on it…targeted use can be very useful as copper is incredible. Heavy and expensive though.
As a heat spreader plate on a heat sink or PCB, for transferring heat from one material to another of a different shape, etc. Basically, any place where performance is the priority over cost, weight, and ease of machining.
I always recommend testing both Al and Cu though when prototyping a high performance spreader/sink as there can be surface smoothness issues and weirdness like that. Cu can’t be anodized either (I think) so that might be an issue for external pieces.
On paper a Cu heat spreader for an Al heat sink might look great but you have to take into account the thermal resistance between the Cu spreader and Al sink. If that connection does not have a very low thermal resistance then the Cu doesn’t help. It would be better to just thicken the Al sink’s base to help with heat spreading.
Oxidation can be an issue for the exposed areas but anything being used for heat transfer should be a gas tight seal to the other metal anyway for good heat transfer.
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Yeah, thanks. Those are the two reasons I didn’t even think about using copper.
But I thought maybe it could be worth it.
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I think you are right CU cannot be anodized. I wonder how noctua does black coolers.
Do they just powder coat or something? That can’t be good for thermals.
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Lol let alone the cost of copper. Let’s make solid copper heatsinks bro. XD
@Battery_Mooch,
Yes of course. My mistake was thinking of it as a finite resistance rather than resistivity. DOY. I was thinking.of it like a bottleneck.
Do thermal interfaces behave like bottlenecks? I assume their conductivity values can be much higher, so even a small layer of air can become a large thermal resistance.
I’ll play with this calculator. The math is simple but I like that it has all the different materials
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I think they electroplate Al onto the Cu and then anodize…clever!
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Material interfaces are very much like resistors. In fact, they call it thermal resistance since you can put them in series and parallel as part of the tradeoff calculations that are done for thickness, surface area, etc.
A high thermal resistance material or interface causes a high delta in temp across the material/interface, just as an electrical resistor causes a delta in voltage. These deltas in temp add up and result in the large difference in temp between the source of heat, perhaps a MOSFET, and the ambient air. Too much of a difference and the MOSFET burns up.
Air has a MUCH higher thermal resistance. Even a 0.0001” gap will completely kill the transfer of heat. It’s critical to fill in the “valleys” in a material’s surface with a TIM (thermal interface material) even if the two surfaces are pressed hard together. Literally, anything is better than air. 
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Remember that the calculator only covers the material thermal resistances. The “connections”, the interfaces between the materials, have a resistance too.
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Ok guys, dumb it down for the highschool junior. John, what would be the most optimal setup in your opinion?
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I would need to know more about the ESC’s design/layout but the biggest ROI would probably be what you’re doing IMO. But the fins need to be outside the enclosure and a TIM must be used. Either a good non-silicone paste or good epoxy in a very, VERY thin layer.
Optimal can mean different things, but if we are optimizing for performance (instead of price, size, or weight) then material choice, thickness (doesn’t have to be the same across the plate), surface finish and plate flatness (planarity), fin design, ESC mounting method, and other things can be tweaked.
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@Battery_Mooch also lmk if you want me to send you one of the current units for testing/analysis.
I saw you were building a board so you can use it properly too lol
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Man I’m in my 30s and I’m lost lol
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Thanks dude. Appreciate it. No need though. Not in a hurry. Got this monstrosity to holding me over. Works awesome. Doesn’t look awesome. Haha
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Sorry guys. 
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