[SOLVED] Painting CPU cooler's heatsink

[Madhava2207]

I recently ordered a black Meshify C. In order to make the system seem uniform, I am considering to paint my CPU cooler's top black. I will not paint any other part like the top of the heat pipes and the fins. I use a Cooler Master Hyper 103. Will that make any difference in cooling performance? Also, will that difference be negligible?
I use an i5-7600 CPU.

 

[Darkbreeze]

Do NOT paint the CPU cooler heatsink. Paint traps heat. Doesn't matter that it's a little or a lot, it does it. Manufacturers that color their heatsinks general use special heat dissipating paints (If at all) or anodize the metal. Painting is simply putting a layer of insulation on the top of the surface and for a heatsink that is a bad idea.

 

[MetallicMonk]

I recently ordered a black Meshify C. In order to make the system seem uniform, I am considering to paint my CPU cooler's top black. I will not paint any other part like the top of the heat pipes and the fins. I use a Cooler Master Hyper 103. Will that make any difference in cooling performance? Also, will that difference be negligible?
I use an i5-7600 CPU.

You could use a chemical to stain the Aluminium fins. I wouldn't recommend it.

 

[Madhava2207]

Thanks. I guess I will wait to upgrade my system to purchase a new CPU cooler.

 

[Bearmann]

Oh, I think I disagree. Most of the heat exchange occurs in the lower fins. Touch the top plate when you are stressing the CPU the most. If it's hot then I would not paint it- there may be significant heat exchange going on there. If it's just a little warm then I think you can paint it. Make sure to cover up the remainder of the heat sink very well while painting. Run something like Realbench before and after with temps from HWMONITOR. Even if you ruin the cooler, it's not very expensive.

 

[Madhava2207]

Oh, I think I disagree. Most of the heat exchange occurs in the lower fins. Touch the top plate when you are stressing the CPU the most. If it's hot then I would not paint it- there may be significant heat exchange going on there. If it's just a little warm then I think you can paint it. Make sure to cover up the remainder of the heat sink very well while painting. Run something like Realbench before and after with temps from HWMONITOR. Even if you ruin the cooler, it's not very expensive.

Thanks for replying! I will have to wait till Wednesday to receive my new motherboard as my old one died. By the way, it went up to 64°C in my old case, an Antec GX200. What do you think of the temperature? Is this okay?

 

[Bearmann]

Thanks for replying! I will have to wait till Wednesday to receive my new motherboard as my old one died. By the way, it went up to 64°C in my old case, an Antec GX200. What do you think of the temperature? Is this okay?

Sure, that temp is fine. Make sure you use a paint safe for temps up to ~250 degrees Fahrenheit. Perhaps look at an automotive parts store.

You will also need to measure your room temp when running the Realbench stress test.

 

[Karadjgne]

You can paint the very top plate, with no discernable difference to temps. Do not paint the rest of the fins. Paint that's applied by the factory is done with specialized paint systems leaving the paint only 1-2 molecules thick and glass smooth so as to not interfere with heat transfer and airflow properties. Paint you get in a spray can is going to be far thicker overall, reducing fin efficiency and lowering the space between the fins, creating non-smooth surfaces etc, lowering airflow efficiency. It's a lose-lose situation for the sake of aesthetics.

 

[Darkbreeze]

Oh, I think I disagree. Most of the heat exchange occurs in the lower fins. Touch the top plate when you are stressing the CPU the most. If it's hot then I would not paint it- there may be significant heat exchange going on there. If it's just a little warm then I think you can paint it. Make sure to cover up the remainder of the heat sink very well while painting. Run something like Realbench before and after with temps from HWMONITOR. Even if you ruin the cooler, it's not very expensive.

That's not great advice to give, especially not really knowing who the target audience is. I'll say it like this.

Anybody knowledgeable enough that they OUGHT to be painting heatsinks, no matter WHERE they are painting them at, certainly has no need to come here and ask the question. For anybody else, and that includes the majority of people, it's a bad idea. Probably the top plate is ok to paint, if you are absolutely, 100% paying attention to detail and not getting ANY on the fins, however, I still disagree with the concept and here's why.

The fins are not even the biggest consideration. The heat pipes are. Those pipes are filled with fluid which vaporizes from it's liquid form then travels to the end of the heat pipe where it dumps it's heat energy and returns to a fluid and then travels back down to the other end of the heatpipe to repeat the process. Painting the top of the heatsink means painting those ends, unless you are supremely careful to NOT get any paint on the ends of the heat pipes that protrude beyond the fins, and that is definitely going to interfere with the efficiency of that process. Nobody can tell me with anything resembling certainty that putting a layer of paint on those heat pipes, (Aside from as Karadjgne mentioned, the specialized process used by manufacturers) without disrupting that delicate balance. Even Bill Owen at MNPCtech, who arguably does the best PC mods in the industry, does not typically paint heatsinks for this exact reason.

 

[Bearmann]

That's not great advice to give, especially not really knowing who the target audience is. I'll say it like this.

Anybody knowledgeable enough that they OUGHT to be painting heatsinks, no matter WHERE they are painting them at, certainly has no need to come here and ask the question. For anybody else, and that includes the majority of people, it's a bad idea. Probably the top plate is ok to paint, if you are absolutely, 100% paying attention to detail and not getting ANY on the fins, however, I still disagree with the concept and here's why.

The fins are not even the biggest consideration. The heat pipes are. Those pipes are filled with fluid which vaporizes from it's liquid form then travels to the end of the heat pipe where it dumps it's heat energy and returns to a fluid and then travels back down to the other end of the heatpipe to repeat the process. Painting the top of the heatsink means painting those ends, unless you are supremely careful to NOT get any paint on the ends of the heat pipes that protrude beyond the fins, and that is definitely going to interfere with the efficiency of that process. Nobody can tell me with anything resembling certainty that putting a layer of paint on those heat pipes, (Aside from as Karadjgne mentioned, the specialized process used by manufacturers) without disrupting that delicate balance. Even Bill Owen at MNPCtech, who arguably does the best PC mods in the industry, does not typically paint heatsinks for this exact reason.

Darkbreeze, first let me say that I know that you are quite knowledgeable and I have a lot of respect for your experience. However, I think that you are being a bit too conservative here. On some heatsinks the top plate can be completely removed and reattached. He said that he would not paint the top of the heatpipes, and even if he did, I'm not sure that it would have an appreciable effect on the cooling. The greatest heat exchange occurs where the the difference between the inner case air temperature and the heatsink temperature is the greatest, all other things being equal such as windspeed and surface area. Thus, the greatest cooling effectiveness would be expected to be at the lower fin areas. Here are some good tips for painting it (WoodenMarker) and a video of a painted radiator (whole thing, not just the top) with little difference in heat transfer:

Would spray-paint hurt a cooler?

I installed a Cooler Master 212 Evo, and it looks ugly as f*ck because it covers half my case window. It's the copper that makes it look the worst. I was thinking about spray-painting the top "fin" (I'm not sure what you call it) so it looks better. Using the power of imagination, pretend I'd put...

linustechtips.com

Actually, I think Karadjgne agreed with my answer when he stated, "You can paint the very top plate, with no discernable difference to temps."

Now what we need is more replies from people who have actually done it and what their experience was.

 

[Darkbreeze]

The only thing copper on the top of the heatsink, is the heat pipes, so that example is, IMO, not very good.

And I'm sorry, but that's actually not how the internal cooling works on heatsinks. All those fins HELP with dissipating heat, but the PRIMARY method of heat exchange occurs in the heat pipes themselves and if the heat pipe is not significantly cooler at one end than at the other, efficiency in the heat exchange will drop considerably.

https://en.wikipedia.org/wiki/Heat_pipe

That evidence is empirical and unarguable. As to what degree it might affect it, I have no numbers or clarity on that, but anything that affects the delicate balance of the design is probably not desirable.

 

[Bearmann]

The only thing copper on the top of the heatsink, is the heat pipes, so that example is, IMO, not very good.

And I'm sorry, but that's actually not how the internal cooling works on heatsinks. All those fins HELP with dissipating heat, but the PRIMARY method of heat exchange occurs in the heat pipes themselves and if the heat pipe is not significantly cooler at one end than at the other, efficiency in the heat exchange will drop considerably.

https://en.wikipedia.org/wiki/Heat_pipe

That evidence is empirical and unarguable. As to what degree it might affect it, I have no numbers or clarity on that, but anything that affects the delicate balance of the design is probably not desirable.

I don't want to go too far afield, but the greatest area of heat exchange occurs at the fins. If the heatpipes did not have attached fins, the amount of heat lost would be exponentially smaller. There is just not enough surface area there.

 

[Darkbreeze]

The fins don't pick up ANY heat, at all, so without the proper operation of what goes on inside the heat pipe, the presence of the fins would be irrelevant. Like I said, it's a delicate balance and there is NO part that isn't essential to optimal performance. Try snipping the end off the heatpipe and see how much good those fins do. None. They'll do nothing whatsoever.

 

[Bearmann]

The fins don't pick up ANY heat, at all, so without the proper operation of what goes on inside the heat pipe, the presence of the fins would be irrelevant. Like I said, it's a delicate balance and there is NO part that isn't essential to optimal performance. Try snipping the end off the heatpipe and see how much good those fins do. None. They'll do nothing whatsoever.

I think that we will have to agree to disagree. Perhaps someone who has painted their top plate before can chime in with their experience.

 

[Karadjgne]

Both right, sorta, yet both wrong. Sorta.

The fins do pick up heat by being extensions on the heatpipes themselves. The heat pipe transfers the heat away from the cpu, absorbing the heat energy, which in turn is absorbed by the fins. What they do is provide surface area for the heat pipe to transfer heat too. However, they need to be thin as possible, yet still retain rigidity in order to absorb that heat and not warp. Metals are extremely susceptible to being affected by temp changes. It's a constant battle of heating up the fin, and having a fan trying to return that fin to case ambient temp. For this to be successful, the airflow over the fin needs to see as little impedance as possible or too much turbulence is built up and that effects the fins ability to dissipate heat. Paint from a can, even a normal airgun, does not create a glassy surface, (ask any body shop just how much sanding is involved with each coat, and just how many layers of molecules are removed with sanding).

So if you lower the efficiency of the fins, you disrupt the efficiency of the heatpipes to work as intended. You may or may not see any variation in temps under normal loads, but the biggest difference will come in capacity. A 140w hyper212 will work the same as a 120w hyper212 at anything under 100w. But push 120w and the painted cooler is now bunk.

So while both are right as to ability being affected or unaffected, neither has taken capacity into mind.

With a painted cooler, to get equitable temps means raising the fan rpm a little higher, so little to no difference is seen in normal operation, but mess with the heatpipes ability to do its job and capacity takes a nose dive.

As to that rad being painted, same deal, you just took a 300w capacity rad, reduced it 50w and put a 150w load on it, not gonna affect anything. Put a 250w OC on it, bye bye level temps.

Considering how many ppl try to squeeze out maximum OC on budget or the cheapest cooler they can justify, I'd have no issues standing by Darkbreeze's admonition that it's a fools game to paint a heatsink period. 1 or 2 ppl might be successful at it, but it's not for the average user. Sorta like mineral oil pc's, it's been done, successfully, but it's not something that ordinarily should be done, especially just for aesthetics purposes.

 

[Bearmann]

Both right, sorta, yet both wrong. Sorta.

The fins do pick up heat by being extensions on the heatpipes themselves. The heat pipe transfers the heat away from the cpu, absorbing the heat energy, which in turn is absorbed by the fins. What they do is provide surface area for the heat pipe to transfer heat too. However, they need to be thin as possible, yet still retain rigidity in order to absorb that heat and not warp. Metals are extremely susceptible to being affected by temp changes. It's a constant battle of heating up the fin, and having a fan trying to return that fin to case ambient temp. For this to be successful, the airflow over the fin needs to see as little impedance as possible or too much turbulence is built up and that effects the fins ability to dissipate heat. Paint from a can, even a normal airgun, does not create a glassy surface, (ask any body shop just how much sanding is involved with each coat, and just how many layers of molecules are removed with sanding).

So if you lower the efficiency of the fins, you disrupt the efficiency of the heatpipes to work as intended. You may or may not see any variation in temps under normal loads, but the biggest difference will come in capacity. A 140w hyper212 will work the same as a 120w hyper212 at anything under 100w. But push 120w and the painted cooler is now bunk.

So while both are right as to ability being affected or unaffected, neither has taken capacity into mind.

With a painted cooler, to get equitable temps means raising the fan rpm a little higher, so little to no difference is seen in normal operation, but mess with the heatpipes ability to do its job and capacity takes a nose dive.

As to that rad being painted, same deal, you just took a 300w capacity rad, reduced it 50w and put a 150w load on it, not gonna affect anything. Put a 250w OC on it, bye bye level temps.

I agree with everything you have said and nothing I said previously contradicts this. Note that the OP is only talking about painting the top plate, not the entire fin area.

 

[Karadjgne]

Which is fine, as long as he understands that his cooler capacity just dropped and whatever cooler he has is now going to be a level lower in ability. Basically a NH-D15 will be no better than a NH-D14, a hyper212 will be similar to a stock cooler, a cryorig H5 will be closer to a H7...

Linus had a video (don't ask me to find it I can't find specific videos on his *** website) of an all white build. Even painted the AIO white, but was quite specific about not painting the fins, just the visible frame, tubes and pump and covering the unpainted fins with white fans. Linus might be responsible for some seriously dorky ideas at times, but even he has limits.

 

[Bearmann]

Which is fine, as long as he understands that his cooler capacity just dropped and whatever cooler he has is now going to be a level lower in ability. Basically a NH-D15 will be no better than a NH-D14, a hyper212 will be similar to a stock cooler, a cryorig H5 will be closer to a H7...

Linus had a video (don't ask me to find it I can't find specific videos on his *** website) of an all white build. Even painted the AIO white, but was quite specific about not painting the fins, just the visible frame, tubes and pump and covering the unpainted fins with white fans. Linus might be responsible for some seriously dorky ideas at times, but even he has limits.

I really don't expect much change in the temps. In my previous link (post #10), Silver47 did it and reported no change in temps. Hopefully, some other people who have already done it will let us know their experience.

 

[Darkbreeze]

but mess with the heatpipes ability to do its job and capacity takes a nose dive.

I don't see where you figure I'm wrong, since this is EXACTLY what I said.

 

[tennis2]

Painting only the top of the top fin does absolutely nothing to the heatsinks cooling ability. Lot of folks not reading the OP carefully.

 

[Karadjgne]

You said fins don't pick up any heat at all. Which is right but not, they don't pick it up as such, what they do is try and remain as cool as possible, and the heatipies get hot and that heat will travel to the cooler temp fin. You also said the paint acts as an insulator, which is also right, but not. It doesn't trap the heat inside the fin, it insulates the fin by preventing the airflow from the fan to cool the fin, so heat energy transfer from the heat pipe is inhibited by lack of efficiency. Basically the same affect in theory as if you jack up case temps, the cooler is less effective at keeping temps down.

 

[Bearmann]

Here is someone who did it:

View: https://www.youtube.com/watch?v=JChWZ9pokaw


No temps, but under comments, another person who tried it states:



masonicN 2 years ago

did you use heat conductive or resistant paint or just normal spray paint?



Diben Dichoso 2 years ago

any paint will do..i just use some acrylic paint and even tried to stress test the CPU..still the same result as before



Madhava2207, give it a try and less us know how it worked out for you Read the label, especially regarding heat tolerance, but I think that plastic dip spray can be peeled off if you don't like it.

 

[Darkbreeze]

You said fins don't pick up any heat at all. Which is right but not, they don't pick it up as such, what they do is try and remain as cool as possible, and the heatipies get hot and that heat will travel to the cooler temp fin. You also said the paint acts as an insulator, which is also right, but not. It doesn't trap the heat inside the fin, it insulates the fin by preventing the airflow from the fan to cool the fin, so heat energy transfer from the heat pipe is inhibited by lack of efficiency. Basically the same affect in theory as if you jack up case temps, the cooler is less effective at keeping temps down.

I said they don't "pick up" any heat, and they don't, at least not from the heat spreader. I did not however, say they don't dissipate any heat. Obviously that's the whole purpose of the heat fins is to transfer heat from the heat pipes to the air passing over and around them. My point was, if you modify the balance of the heat pipes behavior so that the heat pipe doesn't work exactly as designed, then overall the cooler is not going to function 100% as designed, and that INCLUDES the finstack.

I also said it's probably fine if you paint the top of the finstack or "top fin" and are very careful to keep paint OFF of the ends of the heatpipes. If you put a layer of paint on top of the copper pipes on the top of the cooler the cooler is not going to function as well as it would without it, period. I don't care who tries to refute that, it is simply a fact and I already posted the supporting evidence for it.

As for that average users sample of one, I don't know him or her, and have no reason to believe they are any more credible than the guy that was sitting on the sidewalk when I went to Lowe's today.

 

[Karadjgne]

With a name like 'Sammie Techie' and only 4 subscribers after 4 years of work, I tend to agree. It's surprising what some of those ppl on sidewalks know.

 

[cryoburner]

Another possible option, try cutting a thin sheet of plastic of the desired color to fit over the top plate with holes cut for the heat pipes, and stick it on with something like double-sided tape. That way, if it affects performance at all, it could be easily removed.

I suspect that painting the top fin of the heatsink, or even likely the tips of the heat-pipes, wouldn't have any discernible effect on performance though. Those areas are unlikely to perform much heat transfer to the outside air compared to the rest of their length, since they have minimal air passing over them. Some tower coolers even have a plastic shield covering the tips of their heat-pipes. So, I don't think it would be a big concern, especially considering that they are only cooling an i5-7600 here.