Joe34
Active Member
@mahiluana Did you run that closed loop? Or its just passive with empty chamber(no water)?
Pic is too small for me to see
Pic is too small for me to see
Heatsink machining drawing
- Thread starter George2324
- Start date
Joe34
Active Member
Heatsinks don't have to be anodized, but they would be better if they was.
Heatsinks are not Anodized to stop corrosion.
You have a mis understanding of one of the benefits(big benefit too) of anodizing.
Anodizing makes loads of little tiny holes in the material, those holes allow more air to come into contact with the material than if it wasn't anodized. That creates a bigger surface area which would allow for quicker or more cooling capacity.
Edit - Just for the fun part, sometimes you notice bright coloured aluminium electronic devices which are coloured, and you cant scratch the colour off - this is because the fine ink dye is embedded deep into all those tiny holes which the anodizing created - its not a layer of paint on the top. Painting with common paint would likely remove any gain's from anodizing, as the paint would cover all those holes.
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Mullumbimby
Well-Known Member
Stop now pal. You are just making things worse for yourself.
I'm not that smart, but just reading your work is making me dumber. I think I must be absorbing your dumbness through convection, or is it conduction - I cant tell the difference now, but I'm sure I could ten minutes ago..
I think all the stupidity in your post has fucked-up my pc. My whole room is getting stupid and you've killed my dog. He just glanced at your post, then chewed off his own balls.
I used to have a pretty good coffee table but it has just stabbed itself to death, in fear of losing it's intelligence.
You are the literal black hole of brightness. You are sucking the smart from the universe.
I'm losing the will to live, just through knowing that you exist.
Johnnycannaseed1
Well-Known Member
Maybe so because I "stopped" a long time ago
mahiluana
Well-Known Member
it`s aircooled - blowing the air through the tube with the drivers inside.
Scratching a surface with steel brush also generates a bigger surface.
Danielson999
Well-Known Member
I think the part you're not understanding is that we use our heatsinks with forced convection. Think of all the heatsinkUSA extruded aluminum sinks people have with fans mounted on them. Pin-fin sinks also get fans mounted on them. Even if you have no fan mounted on them there is always ambient airflow or tent fans pointed directly at heatsinks.
If you used heatsinks with no ambient airflow in the environment then anodizing would really pay off. When you have airflow hitting your heatsinks (and especially with fans mounted on them) it basically makes anodizing irrelevant. You could mount a fan on an anodized heatsink and a non-anodized heatsink and run them at the temps we typically do growing plants (50-100w) and the temps are going to be almost identical.
I totally understand your reasoning and I've been involved in anodizing 1000's of parts in a previous job and I kinda get why people anodize although some do it for completely different reasons (esthetics/cooling/scratch resistance etc). The issue is there's a massive difference between anodizing's scientifically proven abilites vs how they perform in our grow tents. The balance between conduction, convection and radiative heat transfer is obviously complex and we use all 3 of them to varying degrees. My whole point is pin fin or extruded fin sinks like heatsinkusa benefit 10 times more from forced convection than they do from anodizing. If my black SST-120 heatsinks weren't dyed black right now, they'd still be almost the identical temperature and certainly would be such a negligible difference in temps that it becomes a moot point.
And you're right, painting aluminum wouldn't just remove the benefits of anodizing it would be like putting a blanket over top of your computer. It would have no ability to use convection as a means of heat transfer.
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Joe34
Active Member
@Danielson999 From an anodized perspective it is irrelevant if you use the heatsink w/o a fan, its scientifically proven that anodizing increases the surface area, so a anodized heatsink being better than a non anodized one is still correct.
Your right that in our uses cases, the differences maybe hard to measure and therefore it may not matter if its anodized or not, but anodized is still better.
Also regarding heatsinkUSA, ive already said that you dont have to anodize, and if you are at the point of running a heatsink where it meets your requirements anodized but doesn't non-anodized, then you should really over compensate more on your measurments...
Additional surface area is better.
If I have time, il look at some percentage gains from anodizing, il have a wild guess at its 5-20%
Your right that in our uses cases, the differences maybe hard to measure and therefore it may not matter if its anodized or not, but anodized is still better.
Also regarding heatsinkUSA, ive already said that you dont have to anodize, and if you are at the point of running a heatsink where it meets your requirements anodized but doesn't non-anodized, then you should really over compensate more on your measurments...
Additional surface area is better.
If I have time, il look at some percentage gains from anodizing, il have a wild guess at its 5-20%
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Danielson999
Well-Known Member
George2324
Well-Known Member
I asked the guy if I could get a cheaper deal by not anodised...
He said 0.50 usd cheaper per heat sink.... and said I would not recommend it as it won't look good lol
Bigger heatsink is definitely more expensive than anodising
He said 0.50 usd cheaper per heat sink.... and said I would not recommend it as it won't look good lol
Bigger heatsink is definitely more expensive than anodising
Photon Flinger
Well-Known Member
Maybe so because I "stopped" a long time ago
Johnny, Dan is correct around the black body information. Basically it is something that absorbs all light.
For us the word black usually means a color, but it in this case it is lack of reflection in order to give true measurements of a light source.
So although you are partially correct, he is one step further.
That's the problem with a lot of these debates, there are multiple correct answers.
Regarding mahiluna and his condom heat trapping experiments, the flaw is that he is also measuring the heats coming from the light, not just conductive heat from the cob. Now if he can determine the amount of conductive heat using some other method, then he will know how much energy is in the light.
Sound right guys?
Danielson999
Well-Known Member
The problem with that is that increasing surface area by anodizing is at a microscopic level at best. If I added even a millimeter in diameter of aluminum to my SST120 heatsinks it would add more surface area than anodizing. So in essence, anodizing for the purpose of increasing surface area on our heatsinks helps us so little it just doesn't seem worth it (even if you can get it done for the amazing price of 50c per part!!!).
The only reason I can think of to anodize is to create a thicker layer of oxide (which makes corrosion resistance better) and because it increases emmisivity compared to non-anodized aluminum. But when you throw those two great benefits into a grow tent with fans mounted on or near it blowing air over the heatsink....anodizing has basically no effect and the color of the dye has even less effect.
Joe34
Active Member
@Danielson999 Its at a small level but because it's over the entire heatsink, its worthwhile.
Abiqua
Well-Known Member
probably less than 1% difference between ano and ano free....this has been killed to death
Johnnycannaseed1
Well-Known Member
I hear ya
If you look back at the bottom of my 2nd to last post you will see that I clearly stated that a blackbody does not have to be black... but it just so happens that anything coloured black absorbs all wavelengths of light hence the term blackbody.
I do agree though, that a lot of the time their are multiple correct answers but in this case Danielson is wrong on many points and the questions in my last post calls him out on a lot of that stuff.
Ultimately I stand by my comment that black is the best colour to coat a heatsink, yes it's marginal but just like Formula 1 when you are on the cutting edge all these fractional gains soon add up.
On another note here is an almost truly light absorbing material/coating
https://www.surreynanosystems.com/vantablack
Danielson999
Well-Known Member
You're right it was about color. Here's some things I've learned. The color of a heatsink only affects it's radiative heat transfer ability. Heatsinks use (almost entirely) convective heat transfer to cool themselves up until the surface starts to glow because it's so hot (well over 1000°F).
Because of this and our use of heatsinks in environments with typically good to excellent amounts of airflow, the color of our heatsinks has absolutely no effect on it's cooling ability. There are some who have taken experiments even further and found that anodizing your heatsink black (because black absorbs more heat) actually makes our finned and pin-fin heatsinks perform worse. The reason being that only the outside areas of your heatsink will benefit where convection has the most impact. The area between your fins/pins actually heat each other up, storing heat instead of getting rid of it. They found that having black anodizing for finned/pin-fin heatsinks had no benefits at all because of this negative effect created between the fins/pins. When you think about it, the fins/pins of a heatsink are basically 100% used for releasing the heat (emmisivity). So why color them black and make them absorb heat when you strictly want them releasing it? It would then make sense to color the outside of the sink black and have all the fins/pins either clear or light colored.
The bottom line though is that if we're using forced convection (airflow) to cool our lights, color has no effect and even anodizing has very little effect. Like Abiqua stated in the above post, it's 1% or less at best and it's been beaten like a dead horse for decades. It's pretty simple and complex all at the same time! There are definitely applications where black anodization have great benefit but using them with fans in a grow tent is clearly not one of them.
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Johnnycannaseed1
Well-Known Member
Sure would be nice of you to post evidence and these experiments you mention to back up your claim Danielson
The Leslie cube experiment clearly proves that black is the best emitter of heat radiation, and when you consider heatsinks for LEDs will usually be sitting in ambient air temps of no more than 25 degrees celcius, then a black heatsink is hardly going to pull in more heat than it is emitting, in fact heat transfer is going to be much better under such circumstances so I call Bs on your post so does this infrared footage which clearly proves surface treatment has a visible effect!
"The use of a thermal camera will show the comparison quickly. A piece of masking tape applied across one edge and two walls will show the same reflectivity and confirms that the surface treatment is behind the different radiation characteristics. The image (below) is obtained from a FLIR I7 camera. The left hand side of the cube is matt black and the right hand side is polished copper"
http://www.techknow.org.uk/wiki/index.php?title=Leslie's_Cube
The Leslie cube experiment clearly proves that black is the best emitter of heat radiation, and when you consider heatsinks for LEDs will usually be sitting in ambient air temps of no more than 25 degrees celcius, then a black heatsink is hardly going to pull in more heat than it is emitting, in fact heat transfer is going to be much better under such circumstances so I call Bs on your post so does this infrared footage which clearly proves surface treatment has a visible effect!
"The use of a thermal camera will show the comparison quickly. A piece of masking tape applied across one edge and two walls will show the same reflectivity and confirms that the surface treatment is behind the different radiation characteristics. The image (below) is obtained from a FLIR I7 camera. The left hand side of the cube is matt black and the right hand side is polished copper"
http://www.techknow.org.uk/wiki/index.php?title=Leslie's_Cube
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Danielson999
Well-Known Member
Since I started reading this before realizing it was you I will take the time to answer as best I can.Sure would be nice of you to post evidence and these experiments you mention to back up your claim Danielson
The Leslie cube experiment clearly proves that black is the best emitter of heat radiation, and when you consider heatsinks for LEDs will usually be sitting in ambient air temps of no more than 25 degrees celcius, then a black heatsink is hardly going to pull in more heat than it is emitting, in fact heat transfer is going to be much better under such circumstances so I call Bs on your post so does this infrared footage which clearly proves surface treatment has a visible effect!
"The use of a thermal camera will show the comparison quickly. A piece of masking tape applied across one edge and two walls will show the same reflectivity and confirms that the surface treatment is behind the different radiation characteristics. The image (below) is obtained from a FLIR I7 camera. The left hand side of the cube is matt black and the right hand side is polished copper"
http://www.techknow.org.uk/wiki/index.php?title=Leslie's_Cube
This Leslie cube experiment is fucking stupid.
For this to have any bearing on our application, the cube should have had one side being anodized black and the other being anodized clear (or any other color). Unfortunately you're comparing an excellent emitter of heat (the black side) with one of the worst emitters of heat, polished copper that has an emissivity coefficient of 0.02-0.05. Your matte black 'paint' has a coefficient of 0.96 or so. So please tell me, how does this have anything to do with comparing black anodizing to red/blue/pink etc? We already know that anodizing greatly increases emissivity (even with no color), so does painting it. You didn't really think the Leslie cube experiment proves 'black' is the best color for emissivity did you? To me, this clearly shows that the painted side has much more emissivity than the polished copper side. It has zero to do with color. If that was painted blue or brown it would have had the exact same reading. It was the 'finish' that provided the emissivity, not the color.
Maybe the point you're missing is that black anodizing only affects it's radiative heat transfer properties. The heatsinks in our tents do not use radiative heat transfer to cool, they use forced convection heat transfer (almost entirely but not completely, obviously it's a combination of radiation, convection and conduction). As is stated in many tests/experiments online dating back decades, radiative heat transfer not only maxes out at 25% of total heat emission (in a laboratory under perfect conditions with no air movement) but it also has little to no effect until temperatures reach levels 10 to 20 times those in our heatsinks. All this info is out there for you.
Here's some more for you to digest, although I'm sure you'll find it to be a complete load of BS like everything else that contradicts your line of thinking. 'Energy Exchange' is interesting to note. Since black absorbs more heat it has been shown to be detrimental for fin/pin sinks since the outside of the heatsink benefits most from natural convection. The inner fins end up radiating heat back and forth between each other, driving up the temp compared to it being light colored or better yet, clear coated. It makes sense really, why would you want the fins (that are used to release heat through convection) absorbing heat from surrounding fins? At the very least you'd think we should be limiting this effect, not making it worse by using black. A good example of this 'energy transfer' effect being reduced is when Robin splayed his black anodized pin-fin sinks. The drop in temps was very considerable simply because by splaying it, the pins released much more heat into the surrounding air as opposed to transfering the energy into the bordering pins. Anyway, it's all pretty interesting but obviously there are so many variables that nothing we're talking about is empirical evidence to say the least.
and another from cooliance...
That's because the main cause of thermal energy dispersal from heatsinks works by air flowing across their surface - a process called convection - and not by the heat radiating off of the fins. Because of this, the color of a manufacturer's heatsink surface treatment has limited functional value.
More from Vettecorp HERE
Anodizing:
Aluminum oxide finish, excellent emissivity (important for natural convection), tough finish, low cost, electrically non-conductive, colors are dyed in and do not effect emissivity, black and clear are standard, several automatic lines. RoHScompliant.
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Danielson999
Well-Known Member
Here's a youtube video explaining the anodizing process. It will show you why anodizing's biggest benefit is to prevent corrosion and it will also show you why all those tiny holes you talk about don't actually make the surface area bigger at all if you dye and seal it. The dye fills the holes completely and once it's sealed through hydration sealing (boiling water) or impregnation sealing (de-ionized water) the added surface area is gone. It's my understanding that if you wanted to take advantage of the added surface area created by anodizing then you would stop before the dye and seal stages. Hope this helps a bit.