turtlevette

i remember reading where black bodies give off heat better.

Weighing that theory against whether or not the paint will act as an insulator.

another plus of painting is that it will look more like stock.

sjr1971

Black absorbes heat. White reflects heat. In a Cryogenic pump[vacuum pump], it almost never is exposed to light, usually in some dark corner of the vacuum system. The parts are still painted black to attract any heat even in the dark. Thats what you want your radiator to do, namely attract HEAT and disapate it.

SmokedTires

I don't know, if the paint is too thick, couldn't it possibly insulate it and clogg some of the fins, taking away the efficency of the aluminum? Mine works great in the natural aluminum finish

You could always see if alumnum could be black oxide coated, that'll cover it black with minimum thickness, but I don't know if aluminum is compatible with this process.

norvalwilhelm

Why not just leave it. An aluminum rad looks good and does a better job of cooling then a copper/brass one.
I wouldn't paint it.

RC73

Personally, I would not paint it. It may look better, but I would think it would take away from the efficacy. Although I'm not sure to what degree, maybe not much.

Solid LT1

Try looking at a motorcycle shop for black radiator paint. You need to use the proper paint to allow for heat transfer if you are going to paint it and, yes it will work better in black. I left mine in natural finish because I like to look. To each his own.

Older Than Dirt

Eastwood makes a black paint specifically for radiators. I've used it before and it works really good.

turtlevette

thanks, I'll check it out.

not a '76

i had an aluminum intercooler that someone painted black before.

it still worked fine.

the thing is that the fins dont really get painted anywhere that they get rid of heat anyway. so it doesnt effect anything.

Techno

Both brass and aluminum are far better conductors than paint. If the max heat exchange is wanted leave it unpainted.

This color thing gets carried to too much extremes.
An excellent example of this supposed white/black issue is the SR-71. It was painted black when it was a spy plane but is white now that it is a NASA research plane. Even worse the spy plane had white lettering on it for USAF. At the temp it ran at and this color rejection issue it should have warped the panels where the color change was.

ZL1powr

The primary mode of heat transfer for a radiator is convection from the radiator fluid to the radiator material then conduction through the radiator material and finaly convection from the radiator to the air traveling next to the radiator material. A small amount of thermal energy is transfered to the surroundings by thermal radiation. Any coating on the radiator surface adds resistance to the conduction through the radiator material. If the coating is thin enough its effect will be negligable resistance to heat transfer. The emisivity of the surface affects how well the surface looses heat by radiation to the suroundings. Painting a radiator black does not nessesarily increase the emisivity of the surface and depending on the paint can decrease the emisivity. Thus the most likely affect of painting a radiator will be to decrease it's eficiency.

rihwoods

Being that your rad is under the hood,can't see how it would be an issue....Do not see a problem and some aluminum rad folks will provide them with black paint...

MotorHead

Cooling fins for amplifiers, power supllies etc. are painted black and like the post above it does not matter if the part sits in the dark, black paint applied to the aluminum fins cools better.

I learned this when I went to school but never got a real good explanation, even from the teacher as to why this is. I think it has to do with the wave length of the color or something like that

big_G

Damn, can't seem to find a thermo-dynamics engineer when you need one...

Techno

Now red... A red car or boat or plane will always go faster than another color car. Has something to do with the molecular action on the fluid passing it.

turtlevette

i'm waiting to see what twin turbo thinks. That will settle it for me.

although, ZL1powr makes the best argument so far.

JonnHeather

Corey, good luck with all of this. We live in the Midwest and with what we keep doing to our environment on a daily basis I really wonder if someday we are going to see some nasty storms as you are seeing down south. As they say, reap what you sow. Until then, save the wave and make every day count!!!!

Edzred72

I'm not going to argue fore or against painting...
All I'll say is that make sure the paint you use is THIN enough, and you apply it evenly so it won't clog up the fins and create a "hot spot".
Eddie

Twin_Turbo

Color has nothing to do with heat exchange by means of convection like 99,999999% of the heat exchange of a radiator, color does come into play when talking about heat exchange through radiation, which plays a larger role if there is no moving body of air, like in an amp where there is usually no fan.

A black body is best at emitting radiation BUT it's also best at absorbing it so when you have a heat sink of say 100 degrees next to a scorching hot header, guess what the black body will do? Yes it will warm up, so the 0.00000001% of radiaton heat exchange from a black rad will probably heat it up.

Manufacturers also paint stuff black for corrosion protection and because black is the fastest drying color and usually the cheapest.

turtlevette

no paint it will be then.

I just hope i don't get that whitish powerdy corrosion that aluminum can exhibit.