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Building a heatsink... kind of. Solid copper bar or heatpipe?

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jamesavery22

Member
Joined
Jan 22, 2003
I have a very large heatsink, pretty close to 1" x 10 x 10" What I am trying to do is use a micro atx board and make the heatsink the entire top of the case. Then use something like a solid copper bar (about 3 inches in height and inch in diameter) to connect the heatsink and processor. So id put the copper bar ontop of the processor then the heatsink ontop of the bar.

Thing is the only places I can find solid copper bar is onlinemetals.com and ebay. Either way Im going to spend 30$ on just a <12" bar and shipping. Not to mention cuts.

Then I was thinking I could take a TTIC NPH-2, or something similar, rip off the top inch of fins (as the heatpipe column is 100mm in height, about 4 inches), cut a 1" hole in the large heatsink, then extend the heatpipe to the very tip of the heatsinks fins. Thing is the contact area from the side of teh heatpipe and the large heatsink wont be much. Should I just stick with the solid copper bar idea?

I was going to take the retail P4 heatsink, cut a 1" hole in center all the way thoug that, put a solid 1inch diameter x 3inch copper bar in that hole, make it flush with the bottom of the retail heatsink, use some AS epoxy to hold it inplace as well as put a bolt through the center of some of the fins on the heatsink and the copper bar, then lap the bottom of the heatsink and the copper bar so its nice and flush.
Then basically just put the heatsink ontop of the copper bar thats sticking up. Holding everything in place isnt a big deal.

Thing is it would be easier and cheaper for me to just buy one of the cheap heatpipe coolers and hack it up. I dont know what performance that will give me though. Do heatpipes only work well with fins all along the whole column rather than just at the top?

From online metals, for a 12" bar (shortest length I can get) and one cut IM already at 30$ without shipping and it will weigh around 10lbs...

Any input is welcome =)
 
I'm not sure how well that will work. I have worked with various metals. and while it is true that mounting a copper or aluminum block will draw heat away from your work. (for example welding or using a torch) even at these extreme temps the heat distribution does not travel very far along a length of material. It is not like if you heat one end the other is the same temperature over a foot or so. I mean even at a length of a foot one end may be at it's melting point will the other end is several hundred degrees cooler. What I'm trying to say is that while the idea has some merit you are going to have to either cool your massive heatsink to very cold temps to see any sort of a change or come up with a better method for heat transfer then using a several inch piece of solid copper.
 
A heatpipe should work well with bigger distances than the copper pipe. You don't really need fins all over the heatpipe since it's like WC in a way which it brings the hot temp to another area to be cooled, then returns back.
 
The bar of solid copper won't work. For that cross-section and length, you'd need a temperature difference of around 40°C to get 100 watts from one end to the other. I'm just guessin', but I don't think you want your CPU 40° hotter. ;)

With heat pipes it's possible. You'd need to un-fin the end of heatpipes, bend them, and clamp them to the underside of your big heat sink. To get decent heat transfer you'll need to mill insets into the bottom of the sink and make matching clamp blocks; the pipes, sink, and clamp blocks all have to fit tightly together.

Possible, but hard.
 
SwampThing said:
The bar of solid copper won't work. For that cross-section and length, you'd need a temperature difference of around 40°C to get 100 watts from one end to the other. I'm just guessin', but I don't think you want your CPU 40° hotter. ;)

With heat pipes it's possible. You'd need to un-fin the end of heatpipes, bend them, and clamp them to the underside of your big heat sink. To get decent heat transfer you'll need to mill insets into the bottom of the sink and make matching clamp blocks; the pipes, sink, and clamp blocks all have to fit tightly together.

Possible, but hard.

I concur.
 
The distance I am going to go from the IHS of a P4 to the heatsink will be 3 inches, well 2 7/8s anyways. I think Im going to cut up a thermaltake silent tower. I was going on the premise that I was going to win an auction for some cheap copper. I lost that so I no longer have any way to get cheap copper. I dont want to spend 50$ on just a chunk of copper that Im only going to use a fourth of it =\

And Im not OCing this rig at all, just want it silent. Its a 2.6ghz p4 though and will be running FaD so it will still stay hot. Probably end up blowing a house fan in its direction =)
 
i hate to say it, but wat ever happened to aluminum? last i checked its heat stayed pretty constant, in that it transferred its heat from one end to the other fairly evenly.
 
Como said:
i hate to say it, but wat ever happened to aluminum? last i checked its heat stayed pretty constant, in that it transferred its heat from one end to the other fairly evenly.

Uh I dunno =) I can get an aluminum rod or plate cheaper then copper. I was just about to buy a silent tower to rip up and put on my heatsink...
 
Como said:
i hate to say it, but wat ever happened to aluminum? last i checked its heat stayed pretty constant, in that it transferred its heat from one end to the other fairly evenly.


aluminum has a pretty low thermal resistance so it does seem to warm up very evenly, especially compared to steel or something like that. Copper has an even lower thermal resistance though, and will heat up more "evenly" than aluminum.

Copper still won't work very well for what you are doing. The distance if to far, and the temps will be terrable.
 
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