Why aren't we just making our own heatsinks?!

[zovc]

I thought it was a pretty fun watch, but someone actually what sounds like a feasible project for some of you.

"3d print a mold out of plastic, put it in some plaster or smth to make a negative, wait for it to cool and pour molten aluminium on it. Refine the rough edges on that **** and you are good to go."

Could anyone actually do anything like that? What about with copper? (I can't use dollar sign emojis like I would on my phone.)

 

[Kmpkt]

Something like this?

 

[zovc]

Is that from here? it's beautiful!

 

[Kmpkt]

I'm working on getting it made to go along with the Kmpkt Dynamo and the accompanying Pico unit. Basically roughly the same fin structure and heatpipe arrangement as the L9i with the solder pattern of the LP53 and hopefully exposed heatpipes on the base. Also playing around with a couple of shroud ideas, one of which you can see on this render.

 

[ricochet]

Amazing... something to add to my SFF PC along with the Iris 16! Very interested.

 

[zovc]

Yeah, I'd be really interested in hearing how it performs and if I could purchase one myself!

 

[Kmpkt]

When looking at the LP53, it looks to outperform the L9i by about 6-7 degrees celcius. While it has a slightly greater fin size, it also has fewer fins and I believe a smaller aggregate surface area. With that in mind I am hoping most of the difference is due to swapping from aluminum to copper. My cooler should have about 25% more surface area than the L9i as is is designed to be 28mm tall instead of 23mm. I am currently sourcing 92mm x 15mm fans from a couple manufacturers including Akasa and Yate Loon looking for the best balance of performance and sound.

 

[Biowarejak]

Copper is roughly twice as good at conducting heat compared to aluminum, for what it's worth.

 

[Kmpkt]

Yeah that sounds about right. I've actually heard that aluminum is actually better at transferring heat to air than copper and that the holy grail of coolers (short of using silver) is having aluminum coated copper fins. Can anyone confirm this?

 

[Biowarejak]

Usually adding material to your heat sink adds a bit of resistance to its thermal flow, but if it's a thin layer of aluminum on the copper it might not be an issue. Another good question might be the effectiveness of copper tube/aluminum fin radiators vs their all copper counterparts.

 

[Kmpkt]

I think the performance delta between the LP53 and the L9i pretty much answers that one though.

 

[Biowarejak]

Ah, I hadn't looked at that.

 

[Kmpkt]

For reference:

https://hardforum.com/threads/thermolab-cooltek-lp53-review.1923635/

Based on this review, the LP53 outguns the L9i by at least 6-7 degrees celsius in most applications. If you look at the dimensions of the fins on both of those heatsinks you see the following as well:

LP53 fin area: 94mm wide x 23mm high x 52 fins x 2 sides = 224848mm.sq.
L9i fin area: 95mm wide x 21mm high x 54 fins x 2 sides = 215460mm.sq.

There is about 4% more surface area on the LP53 using napkin math, but when you see the small cutouts on either side of the LP53 above the keep out zone, I'd be willing to bet the surface area is roughly equivalent on both units.

Just for interest's sake, the surface area of the unit I showed above:

Kmpkt Cooler: 94mm wide x 26mm high x 54 fins x 2 sides = 263953mm.sq. or 22.5% greater than the L9i.

 

[Biowarejak]

Good read, I see now

 

[zovc]

I'm a little nervous about that 26mm height, I'm sure it makes a difference, but it might end up being too tall to allow airflow in certain sff cases. Granted, I understand you're making it for your case and not necessarily any others. I'd be happy to give it a shot either way!

 

[Kmpkt]

I know that you can get the L9i and a 25mm redux fan into the S4 mini with literally no room to spare. The L9i (23mm) and Redux 92mm (25mm) total up to 48mm. Looking at the Zaber Sentry, they show photos on the website of it built out with a Cryorig C7 which is 47mm tall. !nverse accepts coolers up to 55mm tall, while the DAN A4-SFX accepts coolers up to 48mm in height. While there are cases in development that have a 40mm cap on cooler height (Hutzy XS) and a couple more that are in limited production with similar restrictions (Customod Series), planning around any of these given their current market share would be ill advised for someone trying to introduce a product with broader market share. The Kmpkt cooler and its intended 92mm x 15mm fan would have a total height of 43mm which is well within tolerance of all of the aforementioned cases. With a minimum air gap of 5mm between the top of the cooler and the side panel noise alterations and fan starvation also shouldn't be an issue.

 

[ricochet]

Definitely hope it will be a near silent 92 mm x 15 mm fan at lower rpms!

 

[bledha]

Copper is roughly twice as good at conducting heat compared to aluminum, for what it's worth.

This is accurate (in values ranging from 1.5x to 2x), check out conductivity values at The Engineering Toolbox here, and the Engineers Edge here.

Yeah that sounds about right. I've actually heard that aluminum is actually better at transferring heat to air than copper and that the holy grail of coolers (short of using silver) is having aluminum coated copper fins. Can anyone confirm this?

This sounds right to my pea-brain. Aluminum should allow the heat to GTFO faster as, since its density is much lower (check out table here), it lacks the ability to store the heat as efficiently as copper. So this seems like a perfect idea, better conductivity with copper for heat transfer and aluminum to let it go, let it go...

Silver, interestingly, has a slightly better heat conductivity value than copper (although not by the same margin as Al. vs Cu.) however its density is still quite a bit higher than copper - meaning it would store the heat better and would require more force to remove. So - the holy grail may well be silver fins coated in aluminum (or aluminium, hehe).

Although, from what I know - Al. coated Cu. seems like it would be the best (and most realistic) as you say - at least following thermal rules...

 

[JosephEK]

It would be even more awesome to make your own mold and make your own forge (assuming you have a lot of room to work in a rural area like me) and melt down some aluminum or even better copper I think.

 

[iFreilicht]

"3d print a mold out of plastic, put it in some plaster or smth to make a negative, wait for it to cool and pour molten aluminium on it. Refine the rough edges on that **** and you are good to go."

Could anyone actually do anything like that? What about with copper? (I can't use dollar sign emojis like I would on my phone.)

While that sounds fun, no matter how good copper is as a heat conductor, heatpipes are better. And no matter how thin you can make the fins of a cast heatsink, fins made from sheet metal will always be thinner.

Having thin fins allows for very high surface area and the limited cross-section in those thin fins is counteracted by using heatpipes for heat transfer. It's just a lot more effective. Additionally, if you wanted to do something like this to fit your very specific needs, getting an extruded heatsink and cutting bits off of that is a much cheaper, quicker, and probably better looking solution.