Heat Transfer question

Projects General Guidance
1

Hey

I need some help from someone who knows a little about Thermo Dynamics. I need to transfer heat in my project, the current heat sink is one from a laptop. My question is, if I was to solder a flat copper bar onto this heat sink, would the transfer of heat from one to the other be efficient? Just not note there will not be enough heat to remelt the solder, it has to be permanent and I do not have access to a welding machine. And I only have one shot at this so I can't experiment. If there are any other ideas please let me know!

Thanks

2

if I was to solder a flat copper bar onto this heat sink,

Think about it. How are you going to get enough heat into your heat sink and copper bar to melt solder?
Heat sinks are normally made of aluminum so you can't solder that to copper.
You are best clamping heat sinks together and suing heat sink paste to make the joint efficient.

It is not entirely clear what you want to do.

3

Hey Grumpy_Mike

I read your article on stereoscopic photography, interesting stuff!

Are you saying that the heat from the soldering iron would dissipate before the solder would melt? Sorry about the clarity issue, I am planning on building a cooling system for my laptop. I've tried cooling pads, reapplying heat sink paste and all the usual tricks. According to the supplier it is a design issue and there is nothing that they can do about it. The laptop stays cool in winter, but keeps overheating in summer. I found a nice little thermo-electric cooling pad, only problem is it can't fit into my laptops case, so I thought extending the heat sink to the cooling device I have built would work.

Thanks for the reply!

4

Are you saying that the heat from the soldering iron would dissipate before the solder would melt?

Yes.

How about some forced air from a fan to aid cooling.

5

Well with the exception of the fan in the case there isn't any room. I have a usb powered cooling pad with 4 fans, but that only managed to delay the shutdowns

6

I hesitate to ask, but how were you powering the USB cooling pad?

7

@AWOL; I thought the heat input from powering the cooling pad with the laptop itself would have minimal effect? If not, why make them that way?

8

I thought the heat input from powering the cooling pad with the laptop itself would have minimal effect?

:~
Sorry wrong. That power is going to add to the heat your laptop produces.

why make them that way?

Because the designers had no idea you were going to do this.

9

So designers had no idea that people would power their laptops cooling pads with their laptops? Sorry I'm finding this hard to believe especially considering that it is clearly indicted in the manual/pamphlet that it was intended to be powered like that. Don't get me wrong though I understand how it cause heat, I'll mod the pad to use another power source and see how much it helps.

10

Sorry I'm finding this hard to believe especially considering that it is clearly indicted in the manual/pamphlet that it was intended to be powered like that.

This is your cooler pamphlet not your lap top pamphlet.
Personally I find it a ridiculous product for this very reason. The fan bit fine but a pelter cooler needs to be properly integrated into a system not a bolt on.

11

This is your cooler pamphlet not your lap top pamphlet.

Sorry I thought you meant the designers of the cooling pad, not the designers of the laptop. My mistake.

Thanks a lot for the help! I am going to mod the cooling pad so that it has an independent power source, and take it from there.

12

You often find cheap USB peripherals like this are designed in the far east where they are more interested in designing something to sell rather than something useful.

13

Well, there's Peltier wafers. But I haven't seen one of those used since 486's and early Pentiums.

Industraplate, of Wilmington, Delaware, USA does plate copper directly to aluminum. 302-654-5210

A bi-metal junction will pass heat from the better conductor into the lesser quite well. That's why copper-clad steel pans work so well. The higher Fermi Level of the better conductor actually pushes electrons into the lesser side.

You might also want to look into Seebeck Current as a way to facilitate heat transfer but I dunno if you can make that work for your laptop. People have used it to power electromagnets (apparently since the 1830's but I've seen one Seebeck Motor on Youtube) but it's also a really good passive heat transfer method.

Once done with that, look up the Peltier and Thomson Effects.

14

Yes I think the cooling pad we are talking about is a Peltier pad with a fan.

15

My laptop is a 133MHz Thinkpad that I use to read ebooks with.