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ArcticMyst Security by Avery

A Peek into Ryan's Builds: Heatsinking a Hot Linear Driver

ped

ped

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Fair play to ya, looks like a nice build. I have a couple of those survival laser hosts en route with a very special build planned ;)

Also, this should be in the review section :beer:
 





daguin

daguin

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It's not really acceptable to review ones' own work ;)

Peace,
dave
 
sinner

sinner

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Nice work, You made your point now!! haha!! making a laser is fun for a very few and it is no joke, you cannot eat a sandwich while building a laser so u know what i mean.. Very nice work, keep it up +1
 
RyanElectro

RyanElectro

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haha thanks dude :beer:

P.S. I got some more interesting builds coming up ;)
 
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T

Things

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Sorry but, whats the idea behind having fins on the heatsink on the driver if it's INSIDE the host? If anything it's just going to lower your thermal transfer between the driver and the pill. Convective cooling is useless inside a sealed host.
 
sinner

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The only way this could work is IF, the heatsink is subjected to some kind of air intake (which is not the case),
Or it could also work IF, the thermal paste should make contact with all of the increased surface area (which i believe is same if not better)

And if the thermal paste doesnot fill all the gaps then the increased surface area between the fins would be a disadvantage, i think i explained it to my understanding of how it should work in different circumstances!
 
T

Things

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Using too much paste is actually worse than using none at all. It is only effective in very thin layers. Having a convection cooled heatsink inside a host won't do anything but limit the heat transfer between the driver and pill. There's a reason heatsinks are made of copper ;)
 
RyanElectro

RyanElectro

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Things said:
Sorry but, whats the idea behind having fins on the heatsink on the driver if it's INSIDE the host? If anything it's just going to lower your thermal transfer between the driver and the pill. Convective cooling is useless inside a sealed host.
Click to expand...

I couldn't grind the height of the heatsink any lower as it wouldn't press into the pill then.

edit: I like to think of them as "copper pipes"... that transfer heat as they get cooled moving heat into the pill. No airflow, yes, but still surrounding air & compound helps dissipation of heat nonetheless. :rolleyes:
 
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S

steveclv

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RyanElectro said:
I like to think of them as "copper pipes"... that transfer heat as they get cooled moving heat into the pill. No airflow, yes, but still surrounding air & compound helps dissipation of heat nonetheless. :rolleyes:
Click to expand...

The air and compound heat transfer abilities are waay less effective (approx 200 times) than copper - you would be far better off tinning the heatsink with solder filling the voids and then grinding the surface flat down to the height of the copper. Will increase the heat transfer coefficient by approx 40%.
 
tsteele93

tsteele93

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Things said:
Sorry but, whats the idea behind having fins on the heatsink on the driver if it's INSIDE the host? If anything it's just going to lower your thermal transfer between the driver and the pill. Convective cooling is useless inside a sealed host.
Click to expand...

Those are inexpensive eBay heatsinks and the idea is that you can use them or a slab of Aluminum that most people use, so the Copper should offer more sinking, ideally it would be a solid piece of copper in this use. But those are cheaper than the chunks of copper typically sold on eBay I think.

Aluminum has ~ 2.3 x the specific heat of Copper, but Copper has ~ 3.3 x the mass of Aluminum.

So given equal chunks of Aluminum vs Copper, you should end up with a bit more energy being held in the copper chunk.
 
T

Things

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If they were actually bought that way, then I can see why, though kinda looks like a custom job to me :)

Not hatin on the build, just pointing out to any others who may copy it can save some time.
 
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RyanElectro

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tsteele93 said:
Those are inexpensive eBay heatsinks and the idea is that you can use them or a slab of Aluminum that most people use, so the Copper should offer more sinking, ideally it would be a solid piece of copper in this use. But those are cheaper than the chunks of copper typically sold on eBay I think.

Aluminum has ~ 2.3 x the specific heat of Copper, but Copper has ~ 3.3 x the mass of Aluminum.

So given equal chunks of Aluminum vs Copper, you should end up with a bit more energy being held in the copper chunk.
Click to expand...

These are the copper heatsinks used for your RAM.

Things said:
If they were actually bought that way, then I can see why, though kinda looks like a custom job to me :)

Not hatin on the build, just pointing out to any others who may copy it can save some time.
Click to expand...

Yes, it comes finned and looking beautiful but it wouldn't fit in the pill so I had to grind down the corners & the height quite a bit so it fits nicely
 
S

steveclv

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Every material has a Thermal Transfer Coefficient that determines how quickly heat moves through it - copper (398) is almost twice as good aluminum (237) for this.

The molar heat capacity of copper and aluminum is the same but copper has 3 times the specific heat capacity of aluminum which means for each gram, it takes 0.3 Joules to raise the temperature by 1C - for aluminum it takes 0.9 Joules (approx)

Now, if you know the watts (Joules per second) of wasted heat being generated by your driver and you know the weight in grams of your heatsink, you can calculate how quickly the temperature of that heatsink will rise and how much copper you need for your intended duty cycle. You can also consider the heat transfer between the copper and aluminum body of the host and how that will prolong the duty cycle.

It's where the fun part of building starts for me :)
 
tsteele93

tsteele93

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sinner

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Very nice Steve, there are a few threads like this one that you might like to enter into discussion, you look like you got it all figured out..
 
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