I want copper copper copper! (well... maybe not)

See, there's where I'd compromise. I wouldn't mind a titanium host, and would definitely be willing to tone down the power in the guts to have a solid, awesome looking hosts as those TiMascus ones you got :wave:

I'm pretty sure you're doing it all wrong... you want to have higher thermal conductivity rather than more heat capacity... the higher the heat capacity.. the longer it will take for the material to absorb the heat.. thus causing a backfire on your your diode... giving a positive feedback in heat gain and thus destroying your diode.... you want to have the whole thing in copper... and have the host in aluminum or have both in full copper... the reason being, is that there is more volume of copper (high thermal conductivity material) to spread out the heat. and eventually dissipating it to the surrounding air. Like i said, IF you had used Iron, Nickel or Steel, it would take a lot longer for it to absorb the heat and dissipate it.

And another thing to take into account is the proportions of the materials properties... this being Thermal Conductivity and Specific Heat of the materials compared and plotted to a line chart to analyze it properly. Copper has a Thermal Conductivity Btu / (hr-ft-F) of 231, and has a Specific Heat (Btu/lb/F) 0.095.... NOW that against lets saay... mild steel....would be 26-37 Thermal Conductivity, and 0.12 Heat spec....now compare those both. and tell me that mild steel is more advantageous. didnt think so... and mild steel rusts like a bitch... so lets use 304 grade stainless steel... that has a thermal conductivity of 8.08 and heat spec of 0.120.....again not very good in heat absorption:heat dissipation. my point is... copper is the only affordable choice of metal for this type of application. copper is one of the best thermal conductor : thermal absorption... i would make a ratio to ratio comparison, but Ive no time to work it all out... you can just imagine what the ratios of the selected metals would be compared to copper..... and it doesn't even come close. of course you could use Diamond gold or silver.... but we know that they are all very very expensive to use... so copper is your only choice.

one more thing, the higher density of copper is also good as it would require less surface area... for example. 10cm in diameter of copper dissipates lets say 10W of heat ( this is not accurate its just an example) and if you were to use stainless steel, you would probably need half a meter in diameter of it to have the same heat dissipation.

:beer:

Your missing "emissivity", if you want the best output from a heatsink, paint it black. And not just any black. While a minor component, how a heatsink behaves as a "black body" radiator matters.

Surface area is a neglected component in this thread, as well.

Steve

... I think if we want "optimal" heatsinks, we need to make them either solid copper, or aluminum diode mount with a copper heatsink.

Aluminum for sucking the heat away fast, and copper for holding all of that heat.

Now I have an idea for a cool looking host. Heat pipes on the outside... oh man that would be sexay.

Well, at any rate I am not sure if you saw the thread about RyanSoh3's all copper M140 laser, but there is a nice graph showing just how good an all copper laser modle and sink combo really is.
I am convinced that by going pure copper the output is not only excellently stable, but peak output (mW) lasts much longer. Aluminum can't compare at all. every laser I have that is 445nm in Aluminum shows a large downward swing after about 4-5 seconds of on time. Copper, well
have a look.
http://laserpointerforums.com/f63/props-dogs-best-friend-bushwhacker-73663.html

So... I don't understand: is more important for the heatsink to be a good heat conductor? But I was thinking Function B is more important...
P.S.: Sorry for this post in this old thread.:anyone:

Not an expert, but have some layman experience from flashlights. Assuming handheld laser. I think it depends on if the host can radiate all of the heat heat produced in to the air and into your hand. If it can, conductivity/emissivity are most important. If it can't, then finding a way to increase storage capacity would be more important to extending run time. In flashlight, I try to get the most of both so that I can run the light continuously at the lower and maybe mid level modes, but also have the ability to run at a crazy high level for bursts.

I don't know the formulas for types of materials, finishes, surface area, etc to determine how much heat a particular host can shed into the air and your hand.

This is all good and well with the chart showing the different metals but I am wondering if Iron and nickel and steel are that much better then
why do all the high power audio amplifiers in this country use aluminum heat sinks and why do expensive stable lasers like the Coherent CUBE
have gold plated copper heat sinks and why do computers use aluminum and copper heat sinks and why then do expensive cooking pans have
a copper plate welded to there bottoms when the are made from steel or aluminum :thinking:

Where is the part I must be missing...


............................................................

It is correct if I want to make a high powerful laser(I mean one that get hot very fast) to use an copper module and an aluminium heatsink? Copper module to transfer fast the temperature from the diode to the heatsink and aluminium heatsink to cool the diode.

Just asking...

BurningLaserGuy said:

It is correct if I want to make a high powerful laser(I mean one that get hot very fast) to use an copper module and an aluminium heatsink? Copper module to transfer fast the temperature from the diode to the heatsink and aluminium heatsink to cool the diode.

Just asking...

Click to expand...

What would be better is a copper module and a copper heat sink.

This means the cooling system will get hot very fast and the heat will be transfered in the air, but I think the aluminium heatsink is better for shorts duty cicles. If I'm wrong please tell me.:undecided:

BurningLaserGuy said:

If I'm wrong please tell me.:undecided:

Click to expand...

Yes you are wrong, copper outperforms aluminum in thermal conductivity and capacity, making it better for heat sinking.

Thanks but I still don't completely understand why. If you can explain me like to a child, please do it.:can:

**EDIT**: If not I'll stop asking stupid questions.

It's ok they aren't stupid questions, but you're at a point where some self study/reading will be more beneficial than some spoonfeeding.

http://en.wikipedia.org/wiki/Heat_capacity

http://en.wikipedia.org/wiki/Thermal_conductivity

I think each material having a conveyor belt of cups to move water from point A to point B. Some materials have bigger cups, some materials have faster conveyor belts.

Thanks for those links, I'll read them but I don't longer need them, a friend of mine explained me today. There are a few ecuations that I don't understand, I'm not even at licceum yet. But no matter... I've find out what I wanted.