How about painting a HS black?

L337 M33P · Jun 11, 2003

Ok a heatsink gets hot enough to radiate infra-red radiation, in the same way that the central heating in your house works. Heatsinks and radiators (in the house, not a WCing setup) work at comparable temperatures, and you can FEEL the heat coming off a white-painted radiator...

So why not spray paint the outside of a heatsink black? It would decrease the albedo and so increase it's thermal radiative coefficient or whatever, reducing temps.

Anyone wanna try?

Mizzery · Jun 11, 2003

I've always wondered about this myself. Waiting for someone to try it

Joe_Atlanta · Jun 11, 2003

One of the oldest debate subjects, from newsgroups and BBS. Upshot is that it makes little measurable difference (unless the heatsink is directly exposed to the sun

).

CamH · Jun 11, 2003

Lots of older heatsinks used on 486es and Pentiums were pained black...

Mizzery · Jun 11, 2003

I know of one guy who painted all his water cooling components black, but that was just so he could read temps with an infared device.

asw7576 · Jun 11, 2003

I rather spent my time going to a computer shop and buy real heatsink.

Toysrme · Jun 11, 2003

Then again lots of HS on old pentiums were gold colored...
Color makes no differance what-so-ever.

L337 M33P · Jun 11, 2003

Heh but you'd get a cool-looking heatsink though (pun intended

)

Cosmetic Mod? Nothing more?

glock19owner · Jun 11, 2003

Toysrme said:
Then again lots of HS on old pentiums were gold colored...
Color makes no differance what-so-ever.

Wrong...black absorbs heat better...this is why your car's firewalls are all black and racers paint their engines flat black...if you still don't believe me...sit a black seat out and a white one in the sun for a few hours...then sit in both and see which one is going to burn you the most...just amke sure to wear shorts and no shirt when doing this...this is also why black car interiors are so hot when you open up the doors after sitting in the sun all day...

And if you still don't believe me...another way to prove your comment wrong...dress in all black and go stand in the sun for a little bit...then dress in all white and do the same...dressed in all black you will be a lot hotter then dressed in all white...

amdperson · Jun 11, 2003

Sound like a good Idea, i might try it when i get my new PC.

glock19owner · Jun 11, 2003

Just don't paint a all copper HS...copper absorbs heat better then black does...and if you do paint a HS...put a light coat on it...to heavy of a coat will change the HS's thermal resistance and make it worse off then what it was before you painted it...

DeepScience · Jun 11, 2003

Ya it's all about black body radiation. The local car radiator place reckons they paint them black ONLY for looks and that it doesn't change efficiency at all. But theoretically it should cos black surfaces radiate (and absorb) heat faster than white surfaces.

I'm going to try painting a old fruit tin and fill it with hot water and compare with an unpainted tin on heat loss.

Depends on the paint and relative thickness of the metal plates I would presume.

AntmanMike · Jun 11, 2003

White reflects light better than black. Black absorbs heat better than white. Black also gives off heat better than white. Not by much at all though.

Do NOT paint it black. THe paint will have very bad thermal characteristics. You want to anodize it.

glock19owner · Jun 11, 2003

ok...well it looks like we all agree black DOES absorbs heat...and I do agree on the anodizing of the HS...but when you can not anodize a HS...say you live in BFE and nothing around...putting a small coat of black paint shouldn't hurt it (IMO)...talking like a light coat...were it just barley covers the original alumin. or whatever the HS is made out of...you still think that light of a coat will effect the HS thermal resistance that much? (negative effect)...

L337 M33P · Jun 11, 2003

Not INSIDE the vanes obviously that would be like wrapping the CPU in a scarf

I mean for a stock HSF can we paint the big metal outside vanes?

Mizzery · Jun 12, 2003

You may paint whatever you like.

I got to thinking and if you paint it black, it will radiate heat better, but conduction to the air in contact with the fins will be reduced. You'll probabally see an increase in temps if you paint it (maybe not with just the ouside). If you annodize it, you'll probabally see the same temps (maybe a nudge up or down)

Toysrme · Jun 12, 2003

Blah blah blah blah blah

Color makes no differance in a ehat sink I'm telling you...

If you want to find out for yourself take a stock black one with an outside source for checking the temps and take the AND off of it... You'll kill two birds with one stone I'm tired of hearing about.

Color makes a differance and so dose AND.

BTW we all know what colors can pickup heat in sunlight ect.

We also all know Ferrari engine bays are lined with actual gold...

Mark Larson · Jun 12, 2003

The color Black only helps when you're absorbing heat by radiation. Almost no heat in a modern-day computer system is dissipated with radiation, only with conduction. I read through half the thread, hoping against hope someone would've paid attention in physics class. Nope.

bananaman · Jun 12, 2003

well black also helps in emitting not just absorbing radiation, but i think as has been said the black paint would just screw up the conduction.

Interesting to note here that radiators in houses should actually be called convectors

NANA

Paxmax · Jun 12, 2003

Black heatsinks

Oookey.. here we go again, this must be about the 5:th time we have this discussion.. with ofcoz different participants.

The outcome of most of theese discussions has been:

YES:
Black surfaces emit/absorb heat better
Painting them black will help emission only at the expense of lowering the convection to surrounding air.
Black anodization is the best way to go, you don't loose that much of regular convection.

Will it help?
Well, yes, but, only OUTSIDE surfaces will emit to surroundings, the black surfaces on the inside of heatsink will only emit to eachother. In practicality total effect won't even be measureable.
Yes, money wasted on paint or anodizing liquids would be better spent anywere else... like bigger heatsink.

Total:
Black surfaces help, but not noticably in our application.

How about painting a HS black?

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