manifold color

[Austin R. Baer]

Re: [mg-tabc] manifold color Got to tell you that home radiators are painted silver because nobody wants them black.. A radiator dissipates its heat much better if it is black, and that's one of the few things I remember from my thermodynamics course that helped me and my Arnolt TC heater stay warm in the fifties.

----- Original Message ----- [b]From:[/b] mrbadger@home.com [b]To:[/b] mg-tabc@yahoogroups.com ; pthelander@earthlink.net [b]Sent:[/b] Friday, January 11, 2002 10:30 AM [b]Subject:[/b] Re: [mg-tabc] manifold color Pete. What you are thinking of in your sunlight test is the ability of a darker color to ABSORB heat in the form of sunlight as opposed to the ability to DISSIPATE heat. I respectfully submit that if you were to take those same two similar objects, one white and the other black, heat them to the same temperature, place them side by side in the dark, you will find that they will cool at precisely the same rate. Car radiators are painted to protect against corrosion. They are black arbitrarily. They would function just as well in any other color, home heating radiators which perform the same function are traditionally painted silver. If car radiators are painted properly, a special non-insulating paint is used which, I believe, is available only in black. Generally, racing cars which need every bit of cooling ability they can get have their radiators left unpainted. A radiator with a polished header tank will have slightly less cooling ability than an unpolished one due to the fact that the polished surface will have less surface area to dissipate the heat. An unrepentant and uncorrected Badger ----- Original Message ----- [b]From:[/b] pthelander@earthlink.net [b]To:[/b] mg-tabc@yahoogroups.com ; roger.46tc@virgin.net ; mrbadger@home.com [b]Sent:[/b] Friday, January 11, 2002 11:49 AM [b]Subject:[/b] Re: [mg-tabc] manifold color Mr Badger Normally I just lurk here in the background while these debates over trivial production details rage endlessly (and I might add in many cases, pointlessly). But when you get to real physical thermodynamic principles, I feel compelled to set the record straight. Your comment that color will not make a "whit of difference" is simply scientifically not true. I invite you to take two objects of the same material and paint one white and one black. Start them at the same temperature and place them in bright sunshine. After some period of time, remeasure the temperature of each and you will find the black one to be warmer. This demonstrates the property of emissivity, the ability to transfer heat. How many fancy show cars with their lovely polished brass radiator tanks have you seen that are chronic over heaters?? It may have been the technological dark ages and they may not have understood the reason, but those early engineers knew enough to paint radiators flat black. They found it worked better. I have had my exhaust manifold finished in an aluminum plasma spray. It comes out with a rough white finish. It looks very much like the original (as best I can recall - at my advancing age, memory is suspect). Most any stains burn off cleanly. The only draw back I have noticed, is that if rubbed with a hard object, the flat white finish can become polished and appear aluminum silver. Respectfully submitted Pete Thelander ----- Original Message ----- [b]From:[/b] mrbadger@home.com [b]To: [/b]mrbadger@home.com;mrbadger@home.com [b]Sent:[/b] 1/11/02 5:23:24 AM [b]Subject:[/b] Re: [mg-tabc] manifold color The actual color of your manifold will make not a whit of difference in dissipating heat however, a coating containing actual aluminum particles may be slightly superior as aluminum is a pretty good heat conductor. Paint in any color may act as an insulation. My personal preference has always been a particular shade of lavender blue poly with a very high metallic content for heat dissipation which I think was original on certain cars. The Badger "................black would be better at dissipating heat, and this is what I used on my Derrington extractor manifold ..............." oc[b]T[/b]agonally Roger

Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. --- Pete and Fran Thelander --- pthelander@earthlink.net Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

[Austin R. Baer]

Re: [mg-tabc] manifold color Got to tell you that home radiators are painted silver because nobody wants them black.. A radiator dissipates its heat much better if it is black, and that's one of the few things I remember from my thermodynamics course that helped me and my Arnolt TC heater stay warm in the fifties. Badger wrote....

......home heating radiators which perform the same function are traditionally painted silver.

[Austin R. Baer]

Re: [mg-tabc] manifold color Got to tell you that home radiators are painted silver because nobody wants them black.. A radiator dissipates its heat much better if it is black, and that's one of the few things I remember from my thermodynamics course that helped me and my Arnolt TC heater stay warm in the fifties. Badger wrote....

......home heating radiators which perform the same function are traditionally painted silver.

[C Sherriff]

Message text written by Ron Simon

>O'gosh, here we go again. In the interests of economy

whilst putting my 1500cc motor together I had my exhaust manifold sand blasted and then nickle plated. It only cost $10.00. It still looks great even after 3 years use,(It turned blue around the hottest parts) but is partially hidden by my Datsun Steering box.

[Peter Pleitner]

Re: [mg-tabc] manifold color Steve, Michael Card is exactly right, assuming we're talking about your exhaust manifold. And Ray is correct about black being much better at heat dissipation. The physics of this is called surface radiant exitance. It is measured as the ratio of the radiance of a "body" to that of a blackbody (a perfect emitter given the value of 1.0). This property is called the emissivity value of the surface or coating. Silver, specifically aluminum oxide flame sprayed and 0.001 inch thick, has an emissivity of 0.765 (1.0 is perfect). For reference, polished aluminum is 0.027. White paint, lacquer in my reference is 0.92, flat black is 0.97 - Infrared Handbook by Wolfe and Zissis. Now to set things straight some more, for performance it is more desirable to contain heat in the exhaust manifold, not cool the exhaust, which slows it down. So, wrap your manifold with asbestos rope, chrome plate it, or get silver Jet-Hot ceramic inside and out for performance . Never mind, take Michael's advise and let me know who is doing it. My quarter century old source in Texas doesn't answer his phone (on earth) anymore. Now, anyone wondering why radiators are black?? Cheers, Peter PS: How the hell did Badger send his rebuttal before I even sent this message???? I better unplug my modem!

[quote] -----Original Message----- [b]From:[/b] Badger [mailto:mrbadger@home.com] [b]Sent:[/b] Friday, January 11, 2002 8:10 AM [b]To:[/b] MG-TABC; Roger Furneaux [b]Subject:[/b] Re: [mg-tabc] manifold color The actual color of your manifold will make not a whit of difference in dissipating heat however, a coating containing actual aluminum particles may be slightly superior as aluminum is a pretty good heat conductor. Paint in any color may act as an insulation. My personal preference has always been a particular shade of lavender blue poly with a very high metallic content for heat dissipation which I think was original on certain cars. The Badger "................black would be better at dissipating heat, and this is what I used on my Derrington extractor manifold ..............." oc[b]T[/b]agonally Roger

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[Austin R. Baer]

Apologies to the group... I hit the "send" button before I finished deleting the appended messages.

Austin

[R. Zwart]

Rusty! Steve Rankin wrote:

FolksWhat is the proper color for a TC manifold?

Steve Rankin TC 6646

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[Dave & Diana Dwyer]

Gentlemen

Normally I too stay out of these 'discussions', but like Peter, I couldn't help my self this time.

What Badger is saying would be more or less correct, #if the devices he cites were really cooling by radiation#. However, they arn't: we may use the term 'radiator' but in fact they are loosing heat by airflow passing over them. Also they are not hot enough to radiate to any degree.

The exhaust manifold on the other hand is a lot hotter and #some# of its heat loss is by true radiation, the balance by air cooling.

On balance Peter is right.

Regards

Dave Dwyer

J2, TA, TC