Can I ask a dumb question? On an aluminum rad,will not cool better painted black than just bare? Yes I have one,and I want to paint it black.but it already runs on the warm side,don't want to make it any less efficient than it is
Had a radiator (aluminum) made for my Avatar and had it powder coated satin black, looks old school and cools perfectly.
Model A Hooligan - You asked the question for me. The new AL radiator in the Chevy is built for as much HP as I'm ever gonna be able to afford. Black would be my choice for the tubes and fins but if bare is best it's going to stay as is. Anodizing seems like the way to color AL without coating .
This is not a scientific answer but I would think that it would cool better painted black if you don't coat it too thick. I bought a used aluminum rad from a dirt tracker once because it fit my application and it was painted black. I have to ***ume that it was for cooling because his car was blue and he wouldn't have wasted paint on the rad if he didn't think it needed it. It certainly wasn't for looks.
Remember the radiators that heated school houses and such years back? It seemed like they always painted them silver. They would have produced more heat if they'd been painted black, but fuel was cheap in those days and I guess silver looked better.
There actually was a show rod that I remember from when I was a little kid that was black and gold. The grill shell (one of those dual headlight jobbys) was black and if you looked in the hole you could see the radiator core and it was gold.
I wonder if it really makes any difference. I had a radiator shop guy tell me that they cool better unpainted. We never painted the cores on truck radiators (18 wheeler types) I have had painted and unpainted radiators and never any problems. So what the ......?
The old timer at the oldest radiator shop in town mixes cheap black enamel with kerosene and sprays a light coat on the old cores after repairing them. HRP
I'm good with black. What I really don't like is to see a company name stenciled/painted across it---
Kinda mixed answers porkn****** always tells me what I need to know.so maybe black it will be.I figured bare would cool better. BTW to the shroud comment.I run a pushed fan...my radiator is about a half inch away from the engine so ..not much can be changed
Me too. I mean between the best method (be it unpainted, flat black or whatever) and the worst (thick coat of gloss something) are we talking 2-3 degrees difference or 20-30?
A thin coat of paint isn't going to reduce the cooling efficiency of a radiator by a lot, but its also not going to enhance it either. The color of an object can have an effect on its ability to radiate heat, but a car radiator doesn't rely on radiant heat transfer to get its job done. Car radiators transfer heat by forced convection, and any coating on the surface actually impedes the heat transfer. The heavier the coating, the more it interferes with heat transfer. Because of the tightly spaced fin construction of a typical radiator, any heavy paint reduces cooling efficiency in two ways. There's the obvious insulating effect of thick paint, but the 2nd effect is reduction of the open space between the fins which increases the air pressure drop thru the radiator and reduces the total air flow thru it. At some point, someone mentioned the possibility of anodizing an aluminum radiator. This would be one of the worst things you could do since anodizing creates an aluminum oxide surface. Aluminum oxide is a very effective insulator as its structure is closely related to a ceramic. To answer blowby's question about best to worst surface conditions and the effect on cooling ability, the difference can be even greater than the 20-30 degrees he mentioned. I'd suspect the practice of painting radiators black came about from a desire to have some uniform color on the surface rather than the sort of mottled appearance you get from br*** or copper over time, and that it had nothing to do with heat transfer efficiency. You won't find any sort of coating on common finned tube coils used in any sort of industrial equipment used for process heating or cooling, or in any sort of heating and air conditioning equipment that uses finned tube coils. If this sort of equipment is used in a corrosive atmosphere such that it does need some coating for protection, the coil will be oversized to account for the loss of efficiency that happens due to the coating. Some of this equipment costs more than a new house, and you can bet if 50 bucks worth of flat black paint would enhance its efficiency they'd all be painted black. That doesn't happen.
LOL back in my more psychedelic days I opened my mouth at speed and managed to swallow a ****erfly. Just made me want to **** on a mirror.
Someone mentioned using carbon black. Dry Graphite spray works great as paint on headers and manifolds, I would think it might be the ideal thing for a radiator core as it is an extremely thin coat of "black" carried in a sprayable solvent that dries in about 15 seconds. Would be a far thinner coating than any black paint. Perhaps masking off the bare core, then using actual paint on the top and bottom tanks and mounting rails, remove the masking from the core and give it a light dusting of dry graphite. I just received an aluminum rad in the mail to go in my Falcon, I have never liked the look of anything other than black behind a grille, so I will try out this method and let you all know.
Haha, just researched "graphite on aluminum" apparently its mildly corrosive, so I won't be trying it on my rad. Works great on headers tho....
We built a set of aluminum airplane wings and told not to use pencil or the black wet-or-dry sand paper. The aluminum turns a dark grey around the pencil lines. We first started with w-or-d sandpaper & where it was used the aluminum went an unnatural grey. We rescuffed with 3M sandpads and Alumiprep prior to paint.
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