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  #1  
Old 17-09-12, 10:07 AM
richie richie is offline
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Painting Heatsinks

Hello,

Having searched for this on the internet, so far I have only found pretty uninformed, extreme reactions, and nothing that gives me any confidence in what the poster has put.

I've built a pretty nice computer so far, in a white, black and pastel green theme in a white Corsair 680T, but my Gigabyte Z77-ud5 board has blue anodized heat sinks on the PCH and VRM that is really spoiling the look. Apparently it is not possible to anodized to white so... spray paint.

Is this just a terrible idea, of course it will affect the thermal properties of the heat sink, but by an amount that I care about? The system is water cooled, so heat from GPU and CPU is being dumped outside the case. (I've come to the air section as the board is air cooled, hope this is the right place).

Has anyone tired spraying heat sinks and have any advice on how much they are affected thermally?.

Of course it will be the thinnest coat I can get away with, and I was thinking car spray paint (already have a can from doing a few other non-heat related parts).

Any advice would be great.

cheers

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Old 17-09-12, 11:20 AM
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tinytomlogan tinytomlogan is offline
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With heatsinks like that it will insulate them to a degree, and will indeed increase the chipset and mosfet temps. By how much will only ever be guess work.
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Old 17-09-12, 12:00 PM
Perturabo Perturabo is offline
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If green and black are your other colours why not annodize to one or other of those and not get involved with the whole paint issue. As TTL says it will be difficult for anyone to give you any quantifiable answers.
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Old 17-09-12, 12:53 PM
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PEXON PEXON is offline
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There is no reason that you can't get them sand blasted and re-anodized. Who said you cant do that?
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Old 17-09-12, 12:59 PM
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Quote:
Originally Posted by PEXON View Post
There is no reason that you can't get them sand blasted and re-anodized. Who said you cant do that?
Me. It would ruin the heatsinks and the heatpipes.
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Old 17-09-12, 01:12 PM
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You can sand blast ally, as long as the media is softer than the aluminium.
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Old 17-09-12, 01:55 PM
dotems dotems is offline
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You may be able to get the answers you want posting this question in the modding forum, there are a bunch of people who are very knowledgeable and who may at very least be able to help you chose paint.

Also check out this thread
http://forum.overclock3d.net/showthread.php?t=44299
G-Dubs painted his heatsinks and goes into a bit of detail about how he did it and I'm sure he would be happy to answer some questions for you. As far as I can see you biggest problem is getting the right paints as you want to go for a white paint you want something that will be good with heat and most importantly keep its colour without tarnishing under those condition's this will be the tricky part and I'm not even sure it can be done.
You might want to check and make sure you heatinks aren't getting to hot and if they are go with a black for the heatsinks and balance it out with white on something that won't be getting hot. If they are running cool then you may be able to get away with it although you may want to make sure you keep good airflow to make sure they stay that way. This is just my speculation as I have no experience painting heatsinks and not much experience painting in general, so I would take some of the things I have mentioned and ask some questions over at the modding forum.
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Old 17-09-12, 04:52 PM
richie richie is offline
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Quote:
Originally Posted by PEXON View Post
There is no reason that you can't get them sand blasted and re-anodized. Who said you cant do that?
From what I've been reading about the anodizing process, you can not anodize to white as the molecule for white dye is larger than the holes that are formed in the alu, so it will not take.
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  #9  
Old 19-09-12, 12:08 PM
richie richie is offline
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Hi,


Well firstly thanks for the posts about this, it is appreciated, however I was really hoping for some idea of how much heatsinks are affected by painting them in general. So that left only one thing to do... an experiment!

Ok, for people who don't want to read all of this:


Conclusion Summary
My conclusion is that the paint has little to no affect on the thermal properties of heatsinks and I will be trying this on my Gigabyte z77-ud5. There is still some uncertainty in the results but you'll just have to read all of this to find out why.


Don't Blame me!
I suppose I should state that the following data will not be 100% the same for every heatsink application and this post is meant as for info only, if you paint your heatsink and get bad results, don't blame me - you chose to do it!


The Experiment
I tend to keep old bits of hardware when I get it, because you never know, but recently mainly because of the build of my new computer, I got rid of a load of old bits, how I regretted it! I put together a really crappy set up to test the difference in the heatsinks sprayed and not sprayed. Neither of the heatsinks were anodised just bare aluminium.



The cable management is awesome I know! Though it's hard to tell, the heatsinks have been sprayed white in this picture.


This is a 2.66GHz Celeron and an unknown motherboard. While there is a HDD and DVD in the picture it turned out the HDD did not work anymore and was the only IDE drive I could find laying around. But I wasn't about to give up so ran it without a HDD or DVD.


The System was booted from a USB stick with a live linux distro (openSUSE). lm_sensors was used to monitor the CPU temp and the temp of the chip being cooled by the passive heatsink in the picture above.


The system was left idle for 15 minutes to stabilise the temperatures, then:


For the next 10 minutes the room temperature was noted, along with the temperatures reported by lm_sensors each minute.


The fans were not speed controlled and were just on.


These are the results:


Not painted, system at idle:



Next, the system was put under load using stress http://weather.ou.edu/~apw/projects/stress/


The system was again left for 15 minutes under load, and the temperatures noted as before.

Not painted, system stressed:



Right, we now have base levels for the temperatues of the system. Next the system was taken apart and the heatsinks spray painted. The paint used was Halfords own brand Renault Glacier White (of course the contact area of the heatsinks was masked off and so not painted). Two liberal coats were applied.



The system was reassembled, and the above tests were repeated recording the data for the temperatures at idle and stressed.

Painted, system at idle:



Painted, system stressed:



Not everything went smoothly


I'm not sure if it was when removing the heatsink or when putting it back on, but a plastic clip of the fan assembly that provides the pressure to the heatsink snapped off. I say it's due to the plastic becoming brittle with age, though Peanut (I want to say an aquaintance, but will go with friend has he helped me in this experiment so much, with only a small degree of moaning) would say it was because I was too heavy handed with it. I also blame Intel on the remarkably bad design either way.


This meant that the test was compromised at this point. First I tried zip tying the assembly down, and checked the tempatures in bios, the CPU was high... very high, and nearly ended the experiment. As we had gone so far, I still wanted some data I could use. So the idle test was carried out. This showed a massive increase in the temperature of the CPU but not the other temperature. This seemed wrong as the paint should have affected them both by about the same amount. So looking at the CPU heatsink it became apparent that the zip ties were not working, so we tried putting manual pressure onto it, and this resolved the problem. However, this meant the side panel of the case had to be off to measure the painted set of results which may have increased the air flow, providing better cooling. As the pressure on the heatsink may also now be different, this too may have affected the results.


A further area that may have affected the results was the thermal compound. This occurred to us a little too late. The first set of results had the original compound on, but when painted had new paste added, probably a different brand, which may have different thermal properites. In hindsight, we should have changed the compound for the first test. That said the passive heat sink (to my suprise) didn't have any thermal paste at all, so the results for the “other” temp would not have been affected by this.


A nice graph of the results:



From this graph it would seem that a painted heatsink actually cools better than the non painted ones. Except for the other temperature under load.


I would have to speculate that the drop in temperatures was due to the above errors in the experiment, as it was expected the paint would reduce performance and not improve it. That said when all is taken into account my conclusion has to be, the paint makes very little, if any difference to the performance of the heatsinks.


If I had more old hardware I would have repeated the experiment when the clip broke, to eliminate the errors, but unfortunately I didn't


So over all I have decided based on these results, to try spray painting the heatsinks on my z77-ud5 board. I will try to get similar data when I do paint them (hopefully next few days as I have this week off work) and will post back how it went.


I hope someone finds this useful, and if any one has any comments about how this experiment could have been improved or anything about anything else, please feel free to post them, and I'll try to take them into account for the z77.


Thanks for reading and thanks to Peanut for the help!
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  #10  
Old 19-09-12, 01:15 PM
Perturabo Perturabo is offline
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Really interesting experiment. I would have expected a much more pronounced effect. It will be interesting to see the comparison on your new board also.
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