Has anyone modded a heatsink to make it shorter/smaller?

Nunuji

Caliper Novice
Original poster
Jan 17, 2021
22
8
So the TL;DR is I want to know if anyone has cut or modified a heatsink's FINS to make it fit better or put it somewhere it wasn't meant to fit, and if they have, what was their experience and what was the process like.

THE FULL STORY:
I have an ASRock Deskmini A300 and I love almost everything about it, it has been super fun to work with, and I am getting it to a comfortable place in overclocking, but it's a little toasty. it currently has a stock AMD Wraith Stealth cooler (shroud and standoffs removed to allow it to fit) and that does an okay job for the APU but next to nothing for the VRM, RAM, and M.2.
So I want to replace the stock fan (roughly 95^2x25mm) that is mounted DIRECTLY onto the CPU heatsink with a modified 120^2x15mm fan mounted to the top of the case.

My concern with having a fan mounted on top of the case rather than to mounted directly to the CPU heatsink is that there will be turbulence or stagnant air; because there is no exhaust fan in the tiny case, the overpressure from air being forced downward through the top will interfere with air getting stuck around little bits or in corners where the case doesn't have vents.

But if there is already a 95^2x25mm height fan in there, why not use a 120^2x25mm instead of a x15mm?
Good question! I initially wanted to, but sadly there isn't enough clearance for the RAM if I use a 120^2x25mm. I would have to trim down the fan to something like 22mm tall, and I don't trust myself to do that well enough to not run into balance and noise issues.

So ultimately I was thinking of taking something like a Noctua L9x65 and removing fin height until it fits closely to the 15mm fan. But by my math that means removing something like 21mm of fin height and might be dangerously close to the heat pipes.

Fluid dynamics isn't exactly my area of expertise, so maybe I'm completely wrong about everything and shouldn't worry about it! Let me know what you guys think and if you've had any experience with this kind of thing.
 

Nunuji

Caliper Novice
Original poster
Jan 17, 2021
22
8
I was speaking with a friend and they mentioned they had a spare Wraith Spire cooler, so that might be better/less expensive to mod than a Noctua. I'd still like to hear from anyone with experience cutting/modding heatsinks. :)
 

MrJvr

Caliper Novice
Jan 18, 2021
26
9
What CPU do you have in there? I have a 3000G and took the fan off an old style Spire cooler (with the copper vapor chamber) and it seems happy to run without a fan (although the 3000G is a 35W chip), also lack of airflow on the rest of the components could be an issue.
If you don't mind putting the fan on the outside over the cooler, or better yet a 120mm case fan which is even quieter, it seems to do a fairly decent job :)
 

Nunuji

Caliper Novice
Original poster
Jan 17, 2021
22
8
What CPU do you have in there? I have a 3000G and took the fan off an old style Spire cooler (with the copper vapor chamber) and it seems happy to run without a fan (although the 3000G is a 35W chip), also lack of airflow on the rest of the components could be an issue.
If you don't mind putting the fan on the outside over the cooler, or better yet a 120mm case fan which is even quieter, it seems to do a fairly decent job :)
I went a little crazy and threw a Ryzen 4650g in there. ^^;
Really cool to hear that you passively cooled yours CPU with a Wraith Spire though! I thought about doing that when I had an a6-9500 in there, but I didn't have a spire to try it with and didn't think the stock cooler that comes with the Deskmini would be enough.

Regarding having a fan on the outside, would you just have it exposed, or would you put some kind of filter or guard over it? Also how would you feed the cable into the system, cut a small hole in the backplate?
 

MrJvr

Caliper Novice
Jan 18, 2021
26
9
I went a little crazy and threw a Ryzen 4650g in there. ^^;

Regarding having a fan on the outside, would you just have it exposed, or would you put some kind of filter or guard over it? Also how would you feed the cable into the system, cut a small hole in the backplate?

I should have a 4650G pitching up in the post tomorrow 🙃 I'm sure it will require far more cooling heh.
To be fair I just had the case on its side and rested the fan on top to see how it impacted the cooling of the CPU, after a while I swapped the cooler fan for a 120mm case fan and there was a slight improvement. Having the board vertical will probably improve thermals more as the warm air wont be trying to rise back up into the fan and up out the top instead :)
Fan/cable, some small zip ties to hold the fan in place and I carefully remove the pins from the fan plug, feed the cable through the holes already in the side and put the pins back in the plug :)
You could put some gauze over it but I'm generally well behaved when it comes to fingers and spinney things :)
 

pacc

Minimal Tinkerer
New User
Nov 11, 2019
3
3
Here is some inspiration from my A300: (not taking credit, bought it as presented)



 

MrJvr

Caliper Novice
Jan 18, 2021
26
9
wowsers...
that actually looks really good!
I have an NH-15D I'm tempted to see how it aligns, might even run passively but would cause issues with lack of airflow over the board components.
I put a 240 AIO on the day before yesterday and despite temps being downright awesome, it seems the motherboard wasnt controlling the DC pump from the headers so it was going at 100% constantly which is a bit loud and annoying :|
I got an IS-40X from amazon for £13 delivered next day and the fan is mm from the case so it's quite noisey.
2 minutes in a vice to squash it down so the fins meet the base and there's a lot more clearance and its a heck of a lot quieter.
I should probably stop tinkering for now and get on with work :p
 

FreshGnar

Trash Compacter
Sep 23, 2020
37
65
I am currently working on side project to retrofit a gtx 760 asus heatsink with two nf-a9x14s to my 1660ti ventus xs oc as the stock cooling solution was a bit disappointing.



Still a major work in progress as I still need to remove a bit off the underside (and drill and tap new mounting holes, but that is besides the point)


I enjoy seeing projects where people aren't afraid to go for it hack stuff up especially since you know to avoid the pipes themselves. However in your specific case I would research all cpu cooler options including something like a black ridge or pallas 120 or an IS-47k. I'm not personally familiar with this case so idk how much room you have to work with. Sometimes it's more benificial to prioritize exhausting hot air out than pulling cool air in, just something to keep in mind.
 

Nunuji

Caliper Novice
Original poster
Jan 17, 2021
22
8
Thanks for all the replies so far guys! It's really cool to see some of the things you've done or purchased (I'd love to see more pictures of that hot rod one!).

As for my project/ideas...
I ended up ordering a Noctua L9x65 to get some real world measurements and get a feeling for it. While I think it might be possible to cut one down, it would be veeerrry close to the pipes and I don't trust myself to do it without potentially damaging it, so I ended up returning it.

I then moved on to an IS-40, which I am really happy to report that it DOES work with a 120mm^2x15mm fan if you manage to rig the fan to the inside top of the case. Unfortunately I may have damaged the fan while I was modding it and didn't want to keep sinking money and time into the project (for now).

Ultimately I went with a Noctua NH-L9a, which is what a lot of people recommended from the beginning but I didn't want to deal with due to the price of them. As much as I like Noctua products (from my brief exposure to them), I do feel like they are overpriced. They offer a niche product to a niche community and I think they know that. The real deciding factor was the fact that they had a nickel-plated base plate, whereas the IS-40 has copper pipes and aluminum. In my opinion if you don't need the nickel base, the IS-40 is a VERY good cooler for 1/3 to 1/2 the price.
 

Tuscany

Average Stuffer
Apr 26, 2020
86
33
Maybe late to the party, but this is exactly what I plan to do in the coming weeks.
My Sliger SM550, which has just 55mm CPU fan clearance. While searching for a replacement for Wraith Stealth to cool Ryzen 5 3600, I got the feeling that none of the aftermarket solutions (including NH-L9a) are THAT much better.

After that I pulled the trigger for Ryzen 9 5900X and currently I cool it with modded Wraith Spire - PETG Custom printed 3D bracket + NF-A9x14. Works, but I want to go a bit better.

So I found Wraith Max, to which I will do exactly as you say in your first post - I will cut the fits to up-to 40mm, so I can fit the 14mm fan ontop. From my preliminary measures, it should work and the heatpipes won't be affected. The cooler is anyways a bit V-shaped on the fins, so shouldn't be that hard.

I will report here the results when they happen :)
 

Nunuji

Caliper Novice
Original poster
Jan 17, 2021
22
8
Maybe late to the party, but this is exactly what I plan to do in the coming weeks.
My Sliger SM550, which has just 55mm CPU fan clearance. While searching for a replacement for Wraith Stealth to cool Ryzen 5 3600, I got the feeling that none of the aftermarket solutions (including NH-L9a) are THAT much better.

After that I pulled the trigger for Ryzen 9 5900X and currently I cool it with modded Wraith Spire - PETG Custom printed 3D bracket + NF-A9x14. Works, but I want to go a bit better.

So I found Wraith Max, to which I will do exactly as you say in your first post - I will cut the fits to up-to 40mm, so I can fit the 14mm fan ontop. From my preliminary measures, it should work and the heatpipes won't be affected. The cooler is anyways a bit V-shaped on the fins, so shouldn't be that hard.

I will report here the results when they happen :)
Please do report back, preferably with pictures! I would love to see how it goes.