Heatsink clips not always the best...

Clips? What kind?

Hmmm, stainless conducts heat rather poorly, maybe not so good a choice for heatsink material? bill

Steel has higher thermal _capacity_. Realized that some 47 years ago while designing a regulator for the TOW missile. Survival over time was the important criteria... I had no time to convey the heat away, so I switched to a steel TO-3 to simply "suck up" the heat ;-) ...Jim Thompson

Den tirsdag den 14. marts 2017 kl. 00.15.08 UTC+1 skrev Jim Thompson:

steel is about half the heat capacity of aluminum per weight, and steel weight roughly 3 x aluminium, so ~50% more capacity for the same volume

I didn't remember the actual numbers. I do remember that I simply ran time-of-flight tests. I did have the advantage, that, at that time, I was running the hybrid facility at Dickson Electronics, in Scottsdale, AZ, so I could have prototypes in hours. ...Jim Thompson

The volumetric heat capacity of most (solid) things, (near room temp) is very similar (~3 J/(cc*K) (within a factor of 2.) Since heat capacity is mostly counting atoms..it says that inter atomic spacing is about the same. Inter atomic spacing is mostly about where the (outer) electrons start bumping into each, (Pauli exclusion principle) electrons rule our world. (sorry too many Genny's* tonight.) George H.

Is it counting atoms or molecules? When I was researching high heat capacity substances I found that parafins were unusually high, off the scale relatively speaking. I can only think it was because the molecules are long.

Was that the Pat Pauli-exclusion principle? I think he ran for president a lot.

Too little sleep last night...

Hmm this list the volumetric heat capacity of parafin as 2.3xx

George H.

Duh, no.. a mole of parafin has a lot of atoms! GH

No phase transition. The molar heat capacity is counting molecules rather than atoms or weight. C25H52 is a long chain alkane (same thing as a paraffin) with about 25 times the mass of methane.

Depending on the size of the molecule alkanes can melt at room temperature which gives you about a 10x increase of heat capacity at that temperature. The typical mixture in coconut oil solidifies between

it can be used to store heat in a living environment. Because coconut oil is a mixture the melting point is not sharp and gives a range.

That doesn't sound like a fault common to steel, nor induced by galvanizing. Probably it's a heat-treatment flaw, and stainless would be worse (400 series stainless heat treatment is possible, but the springs won't have the compliance you get with steel). Bronze would be good, though, it work-hardens, so if it's stamped right, it's springy and won't corrode.

Yeah, not entirely sure about the cause, just speculating.

Didn't seem to be anything remarkable about them. Similar to this kind,

All the clips I see, seem to be stainless (perhaps 304, work hardened, avoiding the problems with 400 series?). I wonder if they know something.

Tim

The clippy kind of clip...

Kinda like this, but the lip went the other way, to hook around the heatsink, rather than wedge into a notch:

That kind of clippy clip!

Tim

Nononononono! Clip to clamp device to heatsink.

Tim

Add sponge/wick soaked in water..