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Discussion Starter · #1 ·
well guys, i'm thinking about making a waterblock for the watercooling that i'm making this spring and i was wondering about what thickness would be good for the waterchamber. and also. would aluminum also work for a waterchamber, or even anywhere else on the waterblock, because its a heck or alot cheaper. thanx alot guys for your help in advance
 

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Copper cools much better, but essentially they are the same. Just do not mix copper and aluminum in the same loop. That will cause corrosion.
As long as you keep the chamber the same area as you tube. IE, a 1/2" diameter tube is about .25" in area (5.x.5), so if the chamber is 1" wide, keep it .25" deep.
 

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Here is some actual data and equations on heat transfer that I put together. (I'm a physics student)

Thermal Conductivity of Substances (k in the equation):
(J/m*s*C)
Aluminum: 240
Copper: 390
Iron/Steel: 46
Silver: 420
Water: .57
Air: .024


 

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I made my own waterblock out of aluminum. Aluminum is way easier to machine than copper. My chamber was based off this design

The more material you use, the more heat it will absorb. I used two half inch thick plates(2"x 2" x .5") and one .25 inch thick one. One of the half inch thick plates was used for the chamber and one for the bottom. The top plate was used for the barbs, and mounting holes.

So yeah, theres nothing wrong with building an aluminum block. If you want max heat cond. use more aluminum, but remember to use an aluminum radiator. I'll try to get pics of my setup soon.
 

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Quote:


Originally Posted by JayJay

I made my own waterblock out of aluminum. Aluminum is way easier to machine than copper. My chamber was based off this design

The more material you use, the more heat it will absorb. I used two half inch thick plates(2"x 2" x .5") and one .25 inch thick one. One of the half inch thick plates was used for the chamber and one for the bottom. The top plate was used for the barbs, and mounting holes.

So yeah, theres nothing wrong with building an aluminum block. If you want max heat cond. use more aluminum, but remember to use an aluminum radiator. I'll try to get pics of my setup soon.

You are wrong, you goal is not for the aluminum to absorb heat, but rather transfer it to the water! The equation for Thermal Conductivity is inversley proportional to the thickness of the material, making a thicker water block worse.
 

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The aluminum absorbs the heat, so where does the heat go from there? To the water. Also, the heavier/more massive the block, the more heat it conducts
* copper has a conductivity that is 70% better { 1.70 }
* aluminum has a conductivity that is 59% of the copper one {0.587 }

Thus we take 70% more aluminum and get the

* weight advantage on capacity of aluminum is down to 38% better than copper { 1.38 }
* volume advantage on capacity of copper is increased to 2.38 fold against aluminum { 2.38 }

for a unit length of equally good conduction
So when heat has to be dumped, the more the better, the quicker
the better, the results are :
If weight or cost is a concern, aluminum is favoured,
if volume is a concern, copper is better.
 

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Quote:


Originally Posted by JayJay

The aluminum absorbs the heat, so where does the heat go from there? To the water. Also, the heavier/more massive the block, the more heat it conducts
* copper has a conductivity that is 70% better { 1.70 }
* aluminum has a conductivity that is 59% of the copper one {0.587 }

Thus we take 70% more aluminum and get the

* weight advantage on capacity of aluminum is down to 38% better than copper { 1.38 }
* volume advantage on capacity of copper is increased to 2.38 fold against aluminum { 2.38 }

for a unit length of equally good conduction
So when heat has to be dumped, the more the better, the quicker
the better, the results are :
If weight or cost is a concern, aluminum is favoured,
if volume is a concern, copper is better.

I am not sure where you have learned this, but it is wrong


Just examine the equation for Thermal Conductivity.

dQ/dt = kAdT/D

Thermal Conductivity is directly proportional to the surface area of the material, difference in temperature and inversely proportional to the thickness of the material.

Therefore the only ways Aluminum could have a equal thermal conductivity as copper is the following:
1. Increase the surface area of the Aluminum comming in contact with the processor, this would require a redesign of the processor to make its surface area larger....
2. Increase the constant of conductivity, this would require making the aluminum more dense, which in effect is what you are trying to say... Expect for their is no way to do this

3. Increase the temperature difference, chiller anyone?
4. Make the thickness of the aluminum smaller than that of the copper. But, why not just decrease the thinkness of the copper?

Quote:


Also, the heavier/more massive the block, the more heat it conducts

Mass is not present in this equation that has been accepted by all physicists for hundreds of years. Adding "bulk" to the system will NOT help!
 

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Quote:


Originally Posted by JayJay

* copper has a conductivity that is 70% better { 1.70 }
* aluminum has a conductivity that is 59% of the copper one {0.587 }

This does not make sense? How can copper conduct 70% better than aluminum, but aluminum only conducts 59% that of copper?!?!?!
 

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Discussion Starter · #10 ·
lol hes got a good point there, but still, thanks alot guys for the help with everything. also, there was another thing that i was wondering about. how thick should i make the, shall we say, cover of the water chamber. you know, the part that sits on the cpu. that should be very thin am i correct?
 

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Quote:


Originally Posted by Roxter

lol hes got a good point there, but still, thanks alot guys for the help with everything. also, there was another thing that i was wondering about. how thick should i make the, shall we say, cover of the water chamber. you know, the part that sits on the cpu. that should be very thin am i correct?


Fact: Copper is a better heat conductor of heat than aluminum, thats it, You are going to screw the barbs into the cover, the rule of thumb is to have at least 3 threads in metal, more for acrylic, 1/4' is good.
 

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Quote:


Originally Posted by pauldovi

Quote:


Also the more heavier a block yadda yadda yadda...

Mass is not present in this equation that has been accepted by all physicists for hundreds of years. Adding "bulk" to the system will NOT help!

Perhaps what he is trying to say here is that a more massive block will hold more heat, which is true. Increasing the mass of anything will always increase its capacity for heat. An aluminium block twice as large will hold twice the heat. For an object twice as large to increase one degree in temperature, it needs twice as much heat. The temperature of the cpu block would thus take longer to increase, and with a greater surface area and water path perhaps this could be taken advantage of.

While the transfer rate between cpu die and cpu block would never improve, with clever block design and more water/surface area the transfer rate between block and water could be increased.

This seems like a logical trail of thought until you look up the specific heat capacity of aluminium and copper. The capacity of aluminium is already more than _twice_ that of copper. An aluminium cpu block will hold a lot more heat then a copper one, it will just take longer for that heat to be transfered to the block. What this would do for block design and cooling i really dont know, but i thought i would mention it anyway as it is a valid point that has gone overlooked. There seems to be a terminology confusion here between conduction and capacity.

Probably a useless snippet of information like, but hey, i've just got out of bed.

John
 

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But the goal is not for the block to absorb ANY heat, the only purpose of the water block is to transfer the heat. It is the medium between the processor and the water because you can't put the water directly on top of the processor.
 
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