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96twofourty
09-18-2004, 11:02 PM
I saw this product and wondered if it could be used on intercoolers without effecting the thermal conduction. It would be a cheap alternative to having the unit sent off to have an expensive coating applied. Has anyone had experience with this produce or a similar one?
http://www.eastwoodco.com/images/us//local/products/detail/p13708.jpg
Radiator Black 12 oz Satin Finish

Standard engine paints are too thick for radiator use because they can interfere with heat transfer and block air flow between the cooling fins. Also, standard paint tends to flake off radiator tanks. Radiator Black helps solve this problem. This acrylic enamel factory-finish (85% gloss) withstands 300 degree F., sprays on thick enough to cover completely, yet thin enough to not interfere with heat transfer. Great for heater cores and air conditioning condensers, too! Each 12 oz net wt. can covers 6 sq. ft., most radiators require 2 cans for full coverage. Buy 3 or more and SAVE!
$9.99/can

OHH_
09-19-2004, 03:11 AM
dont see why it would not work. An IC is basically a radiator but instead of cooling water it cools air. i say do it

98s14inaz
09-19-2004, 08:40 AM
I have read that it works. The stuff you want is made by Swain thermocoatings I think. I will probably use it for the uber sleeper look on my car mwhahaha.

_Def_
09-19-2004, 08:02 PM
It will negatively affect heat transfer, but the quesiton is how much.

If you want a dark intercooler, go all out and get it anodized. That won't affect heat transfer much/if at all.

Paint just isn't a good conductor no matter how thin it is.

Or hell, just get a bigger SMIC if you want the true sleeper look.

98s14inaz
09-19-2004, 08:23 PM
It will negatively affect heat transfer, but the quesiton is how much.

If you want a dark intercooler, go all out and get it anodized. That won't affect heat transfer much/if at all.

Paint just isn't a good conductor no matter how thin it is.

Or hell, just get a bigger SMIC if you want the true sleeper look.



That Swain stuff really doesn't act like paint. It doesn't adversely effect temperatures.

_Def_
09-19-2004, 09:10 PM
The Swain stuff is probably a thin oxide of some sort. Will it negatively affect heat transfer - YES. Will this effect be noticeable or even measurable - depends on its properties and thickness.

Putting *ANYTHING* between the intercooler fins/tubes and the airstream will lessen the heat being transfered from the charge air to the airstream, it'd just take some calculations to tell if it'd be enough to worry about.

Honestly, I'm a huge fan of the "sleeper" or low key look, but I just can't see the logic in spending a nice chunk of change to slightly(or not so slightly) hinder the performance of your setup just to go more low key. If you can't tell, I'm way more for performance than cosmetic *anything*.

Like I said, why not just shoehorn in a huge SMIC, or just mount the FMIC where the radiator is now like the SCC Project Silvia did. It'll just look like a radiator with a different fin design and you'll have less charge piping volume.

Kookz
09-19-2004, 11:25 PM
Anodizing it black should only help the heat transfer.

_Def_
09-19-2004, 11:33 PM
Anodizing it black should only help the heat transfer.



How so? It'd only be adding thermal contact resistance for convection.

If you're referring to black body radiation, most polished metals have fairly high emissivities already. Besides radiation heat transfer will account for a negligible amount of heat flux at the temperatures you'd see in an intercooler core so radiation doesn't even begin to factor in.

Adding ANYTHING between the bare core material and the surrounding air stream will impact its heat transfer characteristics. It's just a question of how much.

asad
09-20-2004, 08:55 AM
If you're referring to black body radiation, most polished metals have fairly high emissivities already.



wrong, wrong, wrong.

First of all, polishing *lowers* the emissivity. And aluminum has a low emissivity to begin with. The emissivity of polished aluminum is somewhere around 0.05 or lower. Nasty oxidized aluminum might be somewhere around 0.2 or so.

Kookz' point is that anodizing isn't a coating. The material is still aluminum all the way through.

Asad

SykikCHIMP
09-20-2004, 09:54 AM
just an fyi - but when I asked greddy about the type of aluminum they used in their intercoolers, and told them I need to know b/c I want to get it anodized, they told me:

"We can't give out that information, but what we can say is that you will likely have problems anodizing it"

.. so whatever the hell that means.. http://forums.freshalloy.com/images/graemlins/tongue.gif

shoes59
09-20-2004, 01:31 PM
That Swain stuff really doesn't act like paint.


But Swain's Black Body Emitter coating (BBE) is not very durable. They're only 20 minutes from my office and I've seen FMIC's with this treatment and it doesn't seem to hold up very well. Not to mention the cost to have an average size intercooler coated is $200+.

FWIW I ordered a can of that paint yesterday and will apply a very light coat on my FMIC this winter. I'll post results next spring.

2Fass240us
09-20-2004, 01:52 PM
First of all, polishing *lowers* the emissivity. And aluminum has a low emissivity to begin with. The emissivity of polished aluminum is somewhere around 0.05 or lower. Nasty oxidized aluminum might be somewhere around 0.2 or so.

Asad


Good joerb Assad. As a reference, the emissivity of anadozied aluminum at 300K is 0.84, around 28 times that of polished aluminum (using Asad's #'s)! And like Asad said about it not being a "coating," I don't believe it would adversely affect the convective heat transfer. Radiative heat transfer will be phenomenally better, however.

That being said, this stuff is not anodization in a can, and thus cannot be treated as such. It is essentially a paint that has been *forumlated* as a radiator coating. Unlike anodization, it will negatively impact convective heat transfer simply by virtue of being a coating. Not having completed a heat transfer analysis of an automotive radiator, I am a little hesitant to add this...but I would wager that the majority of the heat transfered from a radiator is via convective means. This is especially the case since I wouldn't imagine the radiator sees temperatures above 372K (210*F).

If it were me, I'd leave the coating alone. Either annodize it (if it's not a GReddy! http://forums.freshalloy.com/images/graemlins/smile.gif ), or do nothing.

2Fass240us
09-20-2004, 01:54 PM
just an fyi - but when I asked greddy about the type of aluminum they used in their intercoolers, and told them I need to know b/c I want to get it anodized, they told me:

"We can't give out that information, but what we can say is that you will likely have problems anodizing it"

.. so whatever the hell that means.. http://forums.freshalloy.com/images/graemlins/tongue.gif


Criminy. I'm not sure why this is, especially not being familiar with the anodization process. But I would imagine it's temperature-related. http://forums.freshalloy.com/images/graemlins/confused.gif Or maybe they told you this as a textbook case of CYA!

asad
09-20-2004, 02:11 PM
Criminy. I'm not sure why this is, especially not being familiar with the anodization process. But I would imagine it's temperature-related. http://forums.freshalloy.com/images/graemlins/confused.gif Or maybe they told you this as a textbook case of CYA!



All the joints in an all-aluminum intercooler are either vacuum-brazed (~1000 deg. F) or welded (~1200 deg. F) -- and anodizing gets nowhere near that. However, there might be some alloys that don't like being anodized, as the alloying elements could react badly with the acids used in the anoodizing process.

Read this, it rules:
http://www.focuser.com/atm/anodize/anodize99.html

Asad

mamaboy
09-20-2004, 06:45 PM
radiator paint or even flat black paint works fine. when you paint the intercooler you only paint the front row of fins. the cooling doesn't even occur there it's in the rear 2/3 of the cooler.

shoes59
09-20-2004, 06:57 PM
radiator paint or even flat black paint works fine. when you paint the intercooler you only paint the front row of fins. the cooling doesn't even occur there it's in the rear 2/3 of the cooler.


I'm no scientist but this seems a logical statement. I still plan to spray a light coating on the front to darken it a bit. My guess is the difference in cooling ability before and after is negligible.

OHH_
09-20-2004, 07:09 PM
I say do it and dont go over board. i am sure if the fins are clogged with paint you WILL see an adverse effect--so dont clog them. A light mist should be fine and the difference negligible

mamaboy
09-20-2004, 07:28 PM
just to let all your worries go away. i asked RoadRaceEngineering who specializes in DSM's and they did it on some of their cars. Mind you they used Krylon. I had the same questions...wouldn't that obstruct airflow and cooling efficiency. what I'm telling you is the explanation I got....which makes complete sense. You take the intercooler hold it straight up and just paint a light coat working down the face of the core really fast. Just spray in one direction...down and not up. Flip it and Reverse It. you can paint your end tanks it'll work fine. i sold my PWR intercooler and the guy ran 15lbs no problem with no adverse effects. Alot of people worry about clogging fins. if you work fast and mist it from a foot away you'll see that that's impossible to do. don't spray into it just spray @ 45deg and you'll be fine.

_Def_
09-20-2004, 08:59 PM
If you're referring to black body radiation, most polished metals have fairly high emissivities already.



wrong, wrong, wrong.

First of all, polishing *lowers* the emissivity. And aluminum has a low emissivity to begin with. The emissivity of polished aluminum is somewhere around 0.05 or lower. Nasty oxidized aluminum might be somewhere around 0.2 or so.

Kookz' point is that anodizing isn't a coating. The material is still aluminum all the way through.

Asad



Sorry, I was thinking of iron, which is usually around the .2-.3 range.

The simple fact is that radiation is such a negligible amount of heat transfer at this level that it is ridiculous. On the order of probably just a few watts or so.

At one point I did crunch the numbers, and it's seriously less than 1-2% of the total heat transfered for most cases of about a 100*F temperature differential between the radiator and the surroundings. Even less once you factor in the hot engine/compartment behind it will let almost no radiation occur(it is almost the same temp as the radiator). The view factor of the radiator to the cool surroundings would be pretty low.

As far as the technicallity of anodizing not affecting convective heat transfer - it does. Alumina has ~6 times LESS thermal conductivity than pure aluminum. Pure Al will oxidize in air over time, but it will only be a few atoms thick - not the few thousands of an inch built up in anodizing. So while the thin layer means it isn't a huge effect, it does negatively impact the performance a small magnitude.

The Nickel layer put on the part in that link you put up could also affect things as well Asad.

2Fass240us
09-21-2004, 09:31 AM
However, there might be some alloys that don't like being anodized, as the alloying elements could react badly with the acids used in the anoodizing process.


You might be onto something here. I also noticed that the link you posted states that other metals "will dissolve" if exposed to the anodization process listed.



Read this, it rules:
http://www.focuser.com/atm/anodize/anodize99.html

Asad


Yes, that link does indeed rule. Thanks for the heads-up.

Radiative heat transfer being a small part of the total HT, with convective being the majority, was confirmed by Def. But my point is that one cannot justify these "coatings" from a heat transfer improvement standpoint because it doesn't seem valid. People more likely justify it by citing the "sleeper" or "stealth" look.