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stainless steel heatsink ?

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kirby

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I am currently building my first laser, a 1W 808nm laser. But now I need a heatsink. I work in a big factory with a huge machine shop so I have access to all the tools i need to make a heatsink. We do not have copper bars though but we do have aluminum and stainless steel. So I was wondering if stainless steel would make a good heatsink or is alumimun better ?
 





Thanks for the quick reply, I guess I will go with aluminum then or maybe I will just buy a copper bar myself, since it's that much better.
 
kirby said:
Thanks for the quick reply, I guess I will go with aluminum then or maybe I will just buy a copper bar myself, since it's that much better.
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Don't stare yourself blind on the thermal conductivity figure alone. Steel might be a relatively poor thermal conductor, but if you want to run things continously, surface area matters just as much. Aluminium or copper are preferable if you can achieve the same shape, but if you can get much more size or surface area using stainless steel, do not hesitate to attempt it!
 
kirby said:
Thanks for the quick reply, I guess I will go with aluminum then or maybe I will just buy a copper bar myself, since it's that much better.
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How strong is your laser? Aluminum should suffice, plus, you can get it for free.
 
Don't let the numbers fool you while stainless is much worse by the numbers, it should still be good for conducting heat away from your diode. Mass and surface area are also important for a heatsink as well.

Personally, I'd use Aluminum because be easier to machine, cheaper to buy, and can be anodized or passivated in many colors. I'd use even use aluminum over copper if I were the one having to machine it.
 
It is a 1W laser and yes both aluminum and stainless steel would be free. They let me take whatever I want.
 
Thats nice, i had a palce like that.
Wish i still did but they went belly up like all the other here in michigan.
But if you can chose you aluminum its lighter and better.
 
kiyoukan said:
Thats nice, i had a palce like that.
Wish i still did but they went belly up like all the other here in michigan.
But if you can chose you aluminum its lighter and better.
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Odd, when i was building RF power amps...i allways found steel the better heatsink despite what the thermal figures said?
 
ped said:
Odd, when i was building RF power amps...i allways found steel the better heatsink despite what the thermal figures said?
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Mass... It takes more heat to raise steel's temperature versus aluminum. Said otherwise, from a closed system standpoint, aluminum will saturate more quickly leading to shorter duty cycles.

If you want FAST cooling use copper or aluminum.
If you want thermal capacity, use copper or steel (or any other dense material).
Copper is both very dense and very conductive. Best of both worlds.

But the bottom line is that if steel (or any other dense metal) can remove heat with an acceptable temperature gradient it will be superior as a heat sink/ballast versus light metals like aluminum. For forced convection heatsinks, aluminum and copper are better because you are not relying on the thermal mass to absorb heat... you are relying on conductivity to transport heat quickly (low temperature gradients) and convection to dissipate the heat.

Thermal Design 101 ;)
 
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Very good explanation of the thermal property.
+1 for you sir.
so if you plan on using a fan cooled heatsink use aluminum, if you plan on putting this into a static air environment aka a box go steel.
(you can have a fan in a box just give it holes then its not static)
 
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If money is not a huge issue and you want the very best try Ag (silver). Highest thermal conductivity of all metals but not usually practical in comparison to Al or Cu.
 
kiyoukan said:
Very good explanation of the thermal property.
+1 for you sir.
so if you plan on using a fan cooled heatsink use aluminum, if you plan on putting this into a static air environment aka a box go steel.
(you can have a fan in a box just give it holes then its not static)
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It will be in a flashlight most likely, It's a 1W diode, how much heat is it supposed to produce ? How long could it stay turned on with a proper aluminum/steel heat sink.

Ramsey_innovations said:
If money is not a huge issue and you want the very best try Ag (silver). Highest thermal conductivity of all metals but not usually practical in comparison to Al or Cu.
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Maybe when I'm more used with lasers. I'm building my first here. Don't really wanna drill in a silver bar and realize i fucked something up =P
 
Just be aware, that IR lasers are infrared lasers, meaning you can not see the beam nor the dot. There will how ever be a faint red "glow" associated with the laser dot, but be aware at class 4 this laser has very high potential for specular reflection and thus, needs proper care of use. Protective eye wear must be worn and must be rated for your lasers wavelength. Also be aware that IR light behaves different in certain situations compared to its visible light counterparts. In 808nm range not so much, but higher into the 1000nm range like emissions of a CO2 laser, the IR light sees glass as opaque, so special attention is needed when working with glass objects.

I do think this can be a potentially good way to move into this hobby, but your first laser, I do highly recommend practicing on a visible wavelength laser, in the class 3a-3b range first. This is how many of us first made our way into the hobby.

Good luck and Copper all the way :D

-Adrian
 
bobhaha said:
Just be aware, that IR lasers are infrared lasers, meaning you can not see the beam nor the dot. There will how ever be a faint red "glow" associated with the laser dot, but be aware at class 4 this laser has very high potential for specular reflection and thus, needs proper care of use. Protective eye wear must be worn and must be rated for your lasers wavelength. Also be aware that IR light behaves different in certain situations compared to its visible light counterparts. In 808nm range not so much, but higher into the 1000nm range like emissions of a CO2 laser, the IR light sees glass as opaque, so special attention is needed when working with glass objects.

I do think this can be a potentially good way to move into this hobby, but your first laser, I do highly recommend practicing on a visible wavelength laser, in the class 3a-3b range first. This is how many of us first made our way into the hobby.

Good luck and Copper all the way :D

-Adrian
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Thanks, even though it's the first laser i build, it's not the first laser i own, i got plenty of green lasers, a 200mw red, and a 5mw violet. Yes I am aware of the dangers of an IR laser and I did buy appropriate goggles for that wavelenght :yh:
 
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