Copper vs. Alu?

mx · 01-26-2006, 09:17 AM

A while back I purchased a big car radiator that I'm going to use to WC my computer.

The salesman at the radiator store had two rad's with the right size and price, one copper and one alu. I wanted to buy the Cu rad but he convinced me that the alu one was much more efficient. They were about the same size and had the same design, the main difference was the material and that the alu rad had plastic tanks and the Cu one had Cu tanks. I asked him if the Al from the rad and Cu from my blocks wouldn't react and clog up. He said that that wouldn't happen if I used glycol. He does this for a living so he must know something I thought and chose the Al rad.

A few weeks later I decided to buy a Swiftech storm block and when I got it i realized just how small the jets are. Even the smallest object would clog them up!

Since I hadn't used my rad yet, I figured I could trade it for the Cu one.
So today I went back to the radiator store and asked if I could trade my Al rad for the Cu one. Sure I could but he didn't have one in the store atm so he asked me to come back tomorrow. He said several times that I'm making a mistake because the Al rad is so much more efficient. I asked him how thats possible when they have the same design and the only difference is the material. Copper does have better heat transfer capability than aluminum, doesn't it? He disagreed with me and mumbled some numbers.

I've read some thermodynamics and Cu IS superior to Al when it comes to heat transfear? Is it a mistake to trade my Al rad for a Cu rad?

mikoto · 01-26-2006, 10:01 AM

Assuming same design, copper is better.
This debate has been settled for years.

Some have said that copper conducts heat better while Alu "releases" it better. This is absolutely false.

In addition, galvanic corrosion IS a problem to consider, especially with components as small as we use. Corrosion inhibition is all fine and good but I would NEVER mix an Alu rad with a Storm block unless my coolant mixture was thick with corrosion inhibitors, and even then I'd always be nervous and forever checking the state of my equipment.

Consider also, the more corrosion inhibitors you use, the worse your coolant becomes. Water has excellent thermal properties, a very high (relatively) specific heat, meaning that per unit of water it can conduct a relatively large amount of thermal energy, and it isn't very viscuous at all. The more additives you introduce the higher the viscosity and the lower the specific heat, making for a slugish coolant. Not what you need for a Storm.

Water really is the best coolant out there. People have experimented with all sorts of ways to improve its thermal handling properties, the most successful imho is the Argon Laboratories solution of copper particles (measured in nanometers in size) suspended in water.

In short, the higher the proportion of water to additives in your loop, the better your coolant is. An aluminum radiator (less effecient than a copper one assuming the same design), necessitates the use of a higher volume of additives that will worsen the thermal characteristics of your coolant and probably not settle the issue of galvanic corrosion.

Consider this; is this man a computer water cooler or is he thinking from a standpoint of automotive use? With extremely hot coolant relative to air, and an extremely powerful fan + forced air from movement of auto + very high levels of anti freeze + no copper in the loop (only brass from heater core which is much less reactive). Which is better? The lighter, cheaper to manufacture aluminum radiator which no doubt performs great under those circumstances, or the heavier, more expensive, copper one? Of course this man sees no need for copper. What difference does 5-10C make in his world?

Marci · 01-26-2006, 10:21 AM

Bear in mind the 2nd-hand car salesman attitude... maybe he can get more for the Cu Rad so is trying to push you to the Ali cos he wants the Cu fer himself... if he's mumbling numbers, he's trying to convince u with half-truths... so his reasoning must be slightly dodgy / self-oriented (if indeed the ONLY difference between the two is Copper and Ali)

mx · 01-26-2006, 10:51 AM

Thank you for your replys. Now there's no doubts, I will definitly trade my Al rad for what ever Cu rad he shows me tomorrow. I've invested too much money in my computer to be able to sleep with both copper and alu in the loop!

I tried to explain about the small jets in the storm block and that my fans won't blow much compared to a fan in a car. But he didn't seem to get it. He's definitly thinking about automotive use.

Quote:

Originally Posted by Marci

Bear in mind the 2nd-hand car salesman attitude... maybe he can get more for the Cu Rad so is trying to push you to the Ali cos he wants the Cu fer himself... if he's mumbling numbers, he's trying to convince u with half-truths... so his reasoning must be slightly dodgy / self-oriented (if indeed the ONLY difference between the two is Copper and Ali)

He's got a very deep hoarse voice and he always smokes. Remindes me of some mafiaboss

And the rad's weren't exactly alike, the alu rad were slightly bigger, but size wasn't one of he's arguments. He just seems to think aluminum is so much better than copper.

I don't think hes trying to fool me. Then he could have just said no when I asked if I could trade my alu rad, it's not like I got a receipt when I bought it so he doesn't have to help me at all. And he went through a lot of trouble to find me a new copper rad. He called lots of pepole and he's gona pick it up him self, free of charge.

metarinka · 01-26-2006, 03:19 PM

sounds like a nice guy at least, computer rads work much differently then car, just in the fact that most are low volume, low pressure with only a marignal difference over ambient. Where as cars the coolant is right around its boiling point and uses forced air. At any rate does aluminum become more effecient at elevated temperatures and at bigger temperature deltas? I know steels thermal resistance and specific heat change at different temperatures.
Also if the radiators were different that alone could warrant some improved performance or what not. I doubt its the case but does aluminum have a lower coefficient of friction with water? are the fins and such built or joined any different? as there's a big difference between mechanical bonds and metalurgical ones when it comes to heat transfer also; spacing, wall thickness, surface finish etc can effect performance
juss wondering if anyone has the lowdown on radiator construction.

Brians256 · 01-26-2006, 04:12 PM

Aluminum radiators are cheaper and weigh less. That's the only reason (I've found) for why car mfg's use them.

Oh, and there is a LOT of information on rad design, but much of the real nitty gritty seems to be trade secrets and/or not passed around.

Long Haired Git · 01-27-2006, 12:26 AM

Performance wise the impact of air flow and coolant flow will make material choice irrelevant for you.
The "copper" radiator is, of course, brass from the perspective of galvanic corrosion: the end tanks and down tubes are brass. Brass is much more "inert" than aluminium, and whilst the end tanks are plastic the tubes are aluminium in most/all aluminium radiators, and that's a LOT more reactive.

Swap it.

mx · 01-28-2006, 10:35 AM

Today I got the new rad. They're usually not open at saturdays but since he didn't get it for me yesterday as he promised he got it for me today. He was in a hurry so I had to get to the store within 10 min if I wanted the rad before monday. It's a 15 min walk so I went all in in my freeroll, lost the money I ran and got there in time. Since he was in a hurry, we just exchanged radiators and then I left. The new rad is about twice as heavy as the old one so I assumed it was made out of copper.

When I got home and started to examin the rad I got suspicious. There's some small scratches on some of the fins and under the black paint it seemed to be some alu colored material. I looked down in one of the holes and all the channels seemed to be made out of the same grey/silver material. I suspect that the new rad is another aluminum rad! The thicker frame and the slightly thicker rad might explain the incresed weight.

Scratch showing alu?

Could there be another explaination?

How can I verify that the rad is made out of copper and not alu? Besides scratching and judging from the color?
The rad is marked with "AKG - A 03/86". Maybe there is some site where I could enter these nubmers and find out more about it? Maybe radiator dealers can search in some database and find out more about it? I'm planing to show the rad to another radiator dealer on monday and ask him about it.

BGP Spook · 01-28-2006, 09:27 PM

http://valitex.ru/AKG/00_AKG_about.pdf

At the end of the pdf is a list of offices and phone#'s.

http://www.akg-gruppe.de/index.php?lang=2

AKG's website with links to pdf files of lots of radiators. Site is in english, but the pdf's are in German. Can anyone read German?

I can not claim to know what the "A 03/86" actually means. But, haveing looked over some of the pdfs I am guessing the 03/86 is the month/year of production. I think the A is the "Getriebe." Which is, I think, a production/performance technology/method.
(I know it is going to be extremely funny when someone actually posts what it all actually means. Then I will be the fool

and can climb back into the hole from which I came.

)

Was there any other information? Do you know for what vehicle the radiator was originally made?

Now, since I have spent entirely too much time on this, I much exit the thread in much the same sudden fashion I entered it.

jaydee · 01-29-2006, 12:48 AM

Those fins and tubes are covered in solder. Make sure it isn't the grey solder you are scratching. Looks like brass fins from the first pick. Also note many people seem to think brass and copper are the same thing... Even in the fab shop I work at the guys are always calling the copper plate we use brass...

mx · 01-29-2006, 05:14 AM

Quote:

Originally Posted by BGP Spook

http://valitex.ru/AKG/00_AKG_about.pdf

At the end of the pdf is a list of offices and phone#'s.

http://www.akg-gruppe.de/index.php?lang=2

AKG's website with links to pdf files of lots of radiators. Site is in english, but the pdf's are in German. Can anyone read German?

I can not claim to know what the "A 03/86" actually means. But, haveing looked over some of the pdfs I am guessing the 03/86 is the month/year of production. I think the A is the "Getriebe." Which is, I think, a production/performance technology/method.
(I know it is going to be extremely funny when someone actually posts what it all actually means. Then I will be the fool

and can climb back into the hole from which I came.

)

Was there any other information? Do you know for what vehicle the radiator was originally made?

Now, since I have spent entirely too much time on this, I much exit the thread in much the same sudden fashion I entered it.

Thank you for your input.
There's no more information. But I would guess that it's not from a porsche or mercedes.

I'm reading trough all pdf's now, it sure would have been easier if I had some more numbers! Babel fish translates getriebe to transmission.

mx · 01-29-2006, 05:24 AM

Quote:

Originally Posted by jaydee

Those fins and tubes are covered in solder. Make sure it isn't the grey solder you are scratching. Looks like brass fins from the first pick. Also note many people seem to think brass and copper are the same thing... Even in the fab shop I work at the guys are always calling the copper plate we use brass...

I scratched a fin untill I came trough it and I didn't get much wiser. It seems to me that it's the same material all the way. And I scratched one of the channels as much as I dared witout finding any new material.

mx · 01-29-2006, 06:52 AM

I thought if it's solder then it should melt before the copper or aluminum. So I fired up the old soldering iron to see what lay hidden beneath.

I cut a corner of a fin and started heating/scratching. The damn solder was hard to remove. But clearly the fins are not made out of aluminum!

This should mean that the rest of the rad is free from aluminum too?

BGP Spook · 01-29-2006, 07:53 AM

Quote:

Originally Posted by mx

Babel fish translates getriebe to transmission.

That would explain why I kept seeing A's and M's.

metarinka · 01-30-2006, 03:07 AM

of the top of my head most rads are resistance brazed. I don't believe they solder because of cost and/or bad joint strength. At any rate how heavy is it? grabbing a small piece of copper or Alu its very obvious one is much denser than the other, I'm guessing a radiator that size would be MUCH heavier. Looks like CU to me, ohh and if you dont' care about looks too much, I would get the powder coating sand blasted off.

mx · 01-31-2006, 05:09 AM

Quote:

Originally Posted by metarinka

of the top of my head most rads are resistance brazed. I don't believe they solder because of cost and/or bad joint strength. At any rate how heavy is it? grabbing a small piece of copper or Alu its very obvious one is much denser than the other, I'm guessing a radiator that size would be MUCH heavier. Looks like CU to me, ohh and if you dont' care about looks too much, I would get the powder coating sand blasted off.

It really is much heavier than my prevoius alu rad.

Would sand blasting it make any noticeable performance difference?

Etacovda · 01-31-2006, 02:58 PM

sandblasting would completely destroy the fins, if done incorrectly. I wouldnt sweat it personally, theres absolutely zero reason why someone would solder/paint a copper rad, then paint/powder coat (i dont think its powder coated...) it, just to decieve you - i think you're being a little bit paranoid.

metarinka · 02-01-2006, 04:33 PM

noticeable difference, I'm not sure, I believe it would increase air flow (more physical space between fins) and of course up thermal conductivity. Noticeable difference I dunno as the powder coating is relatively thin coating. Most sand blasters can be throttled back (or are designed for delicate parts) I am going to sandblast my radiator this friday actually.

mx · 02-01-2006, 05:01 PM

I'll look if there is a sandblaster in the workshop at my university when I build a fan shroud for the rad.

Will you test your rad before and after sandblasting it?

01-26-2006, 09:17 AM	#1
mx Cooling Neophyte Join Date: Oct 2005 Location: Sweden Posts: 73	Copper vs. Alu? A while back I purchased a big car radiator that I'm going to use to WC my computer. The salesman at the radiator store had two rad's with the right size and price, one copper and one alu. I wanted to buy the Cu rad but he convinced me that the alu one was much more efficient. They were about the same size and had the same design, the main difference was the material and that the alu rad had plastic tanks and the Cu one had Cu tanks. I asked him if the Al from the rad and Cu from my blocks wouldn't react and clog up. He said that that wouldn't happen if I used glycol. He does this for a living so he must know something I thought and chose the Al rad. A few weeks later I decided to buy a Swiftech storm block and when I got it i realized just how small the jets are. Even the smallest object would clog them up! Since I hadn't used my rad yet, I figured I could trade it for the Cu one. So today I went back to the radiator store and asked if I could trade my Al rad for the Cu one. Sure I could but he didn't have one in the store atm so he asked me to come back tomorrow. He said several times that I'm making a mistake because the Al rad is so much more efficient. I asked him how thats possible when they have the same design and the only difference is the material. Copper does have better heat transfer capability than aluminum, doesn't it? He disagreed with me and mumbled some numbers. I've read some thermodynamics and Cu IS superior to Al when it comes to heat transfear? Is it a mistake to trade my Al rad for a Cu rad?

01-26-2006, 10:01 AM	#2
mikoto Cooling Neophyte Join Date: Nov 2002 Location: smog Posts: 47	Re: Copper vs. Alu? Assuming same design, copper is better. This debate has been settled for years. Some have said that copper conducts heat better while Alu "releases" it better. This is absolutely false. In addition, galvanic corrosion IS a problem to consider, especially with components as small as we use. Corrosion inhibition is all fine and good but I would NEVER mix an Alu rad with a Storm block unless my coolant mixture was thick with corrosion inhibitors, and even then I'd always be nervous and forever checking the state of my equipment. Consider also, the more corrosion inhibitors you use, the worse your coolant becomes. Water has excellent thermal properties, a very high (relatively) specific heat, meaning that per unit of water it can conduct a relatively large amount of thermal energy, and it isn't very viscuous at all. The more additives you introduce the higher the viscosity and the lower the specific heat, making for a slugish coolant. Not what you need for a Storm. Water really is the best coolant out there. People have experimented with all sorts of ways to improve its thermal handling properties, the most successful imho is the Argon Laboratories solution of copper particles (measured in nanometers in size) suspended in water. In short, the higher the proportion of water to additives in your loop, the better your coolant is. An aluminum radiator (less effecient than a copper one assuming the same design), necessitates the use of a higher volume of additives that will worsen the thermal characteristics of your coolant and probably not settle the issue of galvanic corrosion. Consider this; is this man a computer water cooler or is he thinking from a standpoint of automotive use? With extremely hot coolant relative to air, and an extremely powerful fan + forced air from movement of auto + very high levels of anti freeze + no copper in the loop (only brass from heater core which is much less reactive). Which is better? The lighter, cheaper to manufacture aluminum radiator which no doubt performs great under those circumstances, or the heavier, more expensive, copper one? Of course this man sees no need for copper. What difference does 5-10C make in his world? __________________ "I hate people faggoting up my forums to no good end..." --pH

01-26-2006, 10:21 AM	#3
Marci Cooling Savant Join Date: May 2003 Location: Wakefield, West Yorkshire, UK Posts: 486	Re: Copper vs. Alu? Bear in mind the 2nd-hand car salesman attitude... maybe he can get more for the Cu Rad so is trying to push you to the Ali cos he wants the Cu fer himself... if he's mumbling numbers, he's trying to convince u with half-truths... so his reasoning must be slightly dodgy / self-oriented (if indeed the ONLY difference between the two is Copper and Ali) __________________ www.minimotosidecars.org / www.thermochill.com / www.themusiccollective.co.uk

01-26-2006, 03:19 PM	#5
metarinka Cooling Neophyte Join Date: Jan 2006 Location: Ann Arbor, MI Posts: 34	Re: Copper vs. Alu? sounds like a nice guy at least, computer rads work much differently then car, just in the fact that most are low volume, low pressure with only a marignal difference over ambient. Where as cars the coolant is right around its boiling point and uses forced air. At any rate does aluminum become more effecient at elevated temperatures and at bigger temperature deltas? I know steels thermal resistance and specific heat change at different temperatures. Also if the radiators were different that alone could warrant some improved performance or what not. I doubt its the case but does aluminum have a lower coefficient of friction with water? are the fins and such built or joined any different? as there's a big difference between mechanical bonds and metalurgical ones when it comes to heat transfer also; spacing, wall thickness, surface finish etc can effect performance juss wondering if anyone has the lowdown on radiator construction.

01-26-2006, 04:12 PM	#6
Brians256 Pro/Staff Join Date: Oct 2001 Location: Klamath Falls, OR Posts: 1,439	Re: Copper vs. Alu? Aluminum radiators are cheaper and weigh less. That's the only reason (I've found) for why car mfg's use them. Oh, and there is a LOT of information on rad design, but much of the real nitty gritty seems to be trade secrets and/or not passed around.

01-27-2006, 12:26 AM	#7
Long Haired Git Cooling Savant Join Date: Jan 2003 Location: Sydney, Oz Posts: 336	Re: Copper vs. Alu? Performance wise the impact of air flow and coolant flow will make material choice irrelevant for you. The "copper" radiator is, of course, brass from the perspective of galvanic corrosion: the end tanks and down tubes are brass. Brass is much more "inert" than aluminium, and whilst the end tanks are plastic the tubes are aluminium in most/all aluminium radiators, and that's a LOT more reactive. Swap it. __________________ Long Haired Git "Securing an environment of Windows platforms from abuse - external or internal - is akin to trying to install sprinklers in a fireworks factory where smoking on the job is permitted." (Prof. Gene Spafford) My Rig, in all its glory, can be seen best here AMD XP1600 @ 1530 Mhz \| Soyo Dragon + \| 256 Mb PC2700 DDRAM \| 2 x 40 Gb 7200rpm in Raid-0 \| Maze 2, eheim 1250, dual heater cores! \| Full specifications (PCDB)

01-28-2006, 10:35 AM	#8
mx Cooling Neophyte Join Date: Oct 2005 Location: Sweden Posts: 73	Re: Copper vs. Alu? Today I got the new rad. They're usually not open at saturdays but since he didn't get it for me yesterday as he promised he got it for me today. He was in a hurry so I had to get to the store within 10 min if I wanted the rad before monday. It's a 15 min walk so I went all in in my freeroll, lost the money I ran and got there in time. Since he was in a hurry, we just exchanged radiators and then I left. The new rad is about twice as heavy as the old one so I assumed it was made out of copper. When I got home and started to examin the rad I got suspicious. There's some small scratches on some of the fins and under the black paint it seemed to be some alu colored material. I looked down in one of the holes and all the channels seemed to be made out of the same grey/silver material. I suspect that the new rad is another aluminum rad! The thicker frame and the slightly thicker rad might explain the incresed weight. Scratch showing alu? Could there be another explaination? How can I verify that the rad is made out of copper and not alu? Besides scratching and judging from the color? The rad is marked with "AKG - A 03/86". Maybe there is some site where I could enter these nubmers and find out more about it? Maybe radiator dealers can search in some database and find out more about it? I'm planing to show the rad to another radiator dealer on monday and ask him about it.

01-28-2006, 09:27 PM	#9
BGP Spook Cooling Savant Join Date: Sep 2005 Location: Virginia Posts: 153	Re: Copper vs. Alu? http://valitex.ru/AKG/00_AKG_about.pdf At the end of the pdf is a list of offices and phone#'s. http://www.akg-gruppe.de/index.php?lang=2 AKG's website with links to pdf files of lots of radiators. Site is in english, but the pdf's are in German. Can anyone read German? I can not claim to know what the "A 03/86" actually means. But, haveing looked over some of the pdfs I am guessing the 03/86 is the month/year of production. I think the A is the "Getriebe." Which is, I think, a production/performance technology/method. (I know it is going to be extremely funny when someone actually posts what it all actually means. Then I will be the fool and can climb back into the hole from which I came. ) Was there any other information? Do you know for what vehicle the radiator was originally made? Now, since I have spent entirely too much time on this, I much exit the thread in much the same sudden fashion I entered it. __________________ I can't spell, but I am working on it.

01-29-2006, 12:48 AM	#10
jaydee Put up or Shut Up Join Date: Dec 2001 Location: Spokane WA Posts: 6,506	Re: Copper vs. Alu? Those fins and tubes are covered in solder. Make sure it isn't the grey solder you are scratching. Looks like brass fins from the first pick. Also note many people seem to think brass and copper are the same thing... Even in the fab shop I work at the guys are always calling the copper plate we use brass...

01-29-2006, 06:52 AM	#13
mx Cooling Neophyte Join Date: Oct 2005 Location: Sweden Posts: 73	Re: Copper vs. Alu? I thought if it's solder then it should melt before the copper or aluminum. So I fired up the old soldering iron to see what lay hidden beneath. I cut a corner of a fin and started heating/scratching. The damn solder was hard to remove. But clearly the fins are not made out of aluminum! This should mean that the rest of the rad is free from aluminum too?

01-30-2006, 03:07 AM	#15
metarinka Cooling Neophyte Join Date: Jan 2006 Location: Ann Arbor, MI Posts: 34	Re: Copper vs. Alu? of the top of my head most rads are resistance brazed. I don't believe they solder because of cost and/or bad joint strength. At any rate how heavy is it? grabbing a small piece of copper or Alu its very obvious one is much denser than the other, I'm guessing a radiator that size would be MUCH heavier. Looks like CU to me, ohh and if you dont' care about looks too much, I would get the powder coating sand blasted off.

01-31-2006, 02:58 PM	#17
Etacovda Cooling Savant Join Date: Feb 2004 Location: Dunedin NZ Posts: 735	Re: Copper vs. Alu? sandblasting would completely destroy the fins, if done incorrectly. I wouldnt sweat it personally, theres absolutely zero reason why someone would solder/paint a copper rad, then paint/powder coat (i dont think its powder coated...) it, just to decieve you - i think you're being a little bit paranoid. __________________ Hypocritical Signature I tried to delete: Procooling: where scientific principles are ignored because big corporations are immune to mistakes and oversights.

02-01-2006, 04:33 PM	#18
metarinka Cooling Neophyte Join Date: Jan 2006 Location: Ann Arbor, MI Posts: 34	Re: Copper vs. Alu? noticeable difference, I'm not sure, I believe it would increase air flow (more physical space between fins) and of course up thermal conductivity. Noticeable difference I dunno as the powder coating is relatively thin coating. Most sand blasters can be throttled back (or are designed for delicate parts) I am going to sandblast my radiator this friday actually.

02-01-2006, 05:01 PM	#19
mx Cooling Neophyte Join Date: Oct 2005 Location: Sweden Posts: 73	Re: Copper vs. Alu? I'll look if there is a sandblaster in the workshop at my university when I build a fan shroud for the rad. Will you test your rad before and after sandblasting it?

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