By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum House Ad Zone

Thermal condution paste - none adhesive

For PC heatsinks

All Topics | Latest Posts

Search for:  in Thread Title in  
pgk pgk20/05/2022 14:55:00
2563 forum posts
293 photos

I've just take apart an all-in-one PC and cleaned all the dust and crud out of the fan and radiator and it all works fine and quiet now.
BUT:

The cooling fan blows air into a radiator which houses some thermal conduction bars terminating in sprung flats screwed over the main processors. Clearly there is evidence of a gap-filling compound and I’d appreciate advice on what to use there if it needs doing again - something that will gap-fill but not glue or drip...

pgk

Thor 🇳🇴20/05/2022 15:00:27
avatar
1628 forum posts
46 photos

I assume you mean something like this, various types tested here.

Thor

pgk pgk20/05/2022 16:56:56
2563 forum posts
293 photos
Posted by Thor 🇳🇴 on 20/05/2022 15:00:27:

I assume you mean something like this, various types tested here.

Thor

That's the sorta thing looks like a paste rather tthan liquid for ham-fisted use...

pgk

Brian G20/05/2022 17:51:43
840 forum posts
37 photos
Posted by pgk pgk on 20/05/2022 16:56:56:
Posted by Thor 🇳🇴 on 20/05/2022 15:00:27:

I assume you mean something like this, various types tested here.

Thor

That's the sorta thing looks like a paste rather tthan liquid for ham-fisted use...

pgk

If you are worried about ham-fisted use make sure you get a non-conductive thermal grease. The more expensive high performance "liquid metal" pastes are electrically conductive and if any gets on the pins you may say goodbye to the processor, and there is no need for them unless you are seriously overclocking.

Brian G

Stuart Smith 520/05/2022 20:58:44
278 forum posts
43 photos

CPC list 2 which look suitable:

**LINK**

Stuart

old mart20/05/2022 21:06:09
3772 forum posts
233 photos

I have used Arctic silver 5 for years, but there is some stiction when removing the heatsink, which is unavoidable.

Martin King 220/05/2022 22:21:34
1005 forum posts
450 photos

Hi All,

Interesting thread for me as I have had to remove a large circuit board from a woodworking lathe to have it repaired.

When I undid the retaining screws and went to slide it out of the steel casing the bottom was covered in a thickish white paste.

The manual said this was to aid heat conduction from the alloy heat sink to the casing.

I believe there was a mention somewhere else in my research that this would be Zinc Oxide paste.

Would this be correct and is it the same Zinc Oxide as the old fashioned ointment of the same name?

Cheers, Martin

Peter Greene 🇨🇦20/05/2022 22:48:31
510 forum posts
6 photos

CPUs are normally mounted using silver conductive compound which is much less fussy about film thickness than straight silicone which is non-conductive and relies on a very thin, gap-filling application to do its job. AFAIK all the cpu manufacturers recommend/require it (silver).

That doesn't mean you put it (silver) on by the spoonful though. A thin wipe all over the CPU cover is enough to give a decent thermal connection to the heatsink (better than silicone).

Shorting out pins is greatly exaggerated. It's like a grease film. If you couldn't apply a thin film of that locally without getting it all over the pins you wouldn't be here.

Personally, if the original heatsink connection hasn't been broken, I'd leave it alone. It's most unlikely that you'll improve it. Cleaning out the crud that gathers around the fan and heatsink though with a vacuum cleaner is well worth doing from time to time, especially if you do any intensive processing (such as video editing). If you run a background cpu temperature-checker before and after clearing out the dirt you'll certainly notice a difference.

pgk pgk21/05/2022 05:30:38
2563 forum posts
293 photos

As described above in this specific case the radiator, coolant bars and coolant pads are inseparable such that the cleaning process required the pads to be lifted. I do own a conductive epoxy but avoided using that in case of future need to repeat the cleaning.
As it happens, I just re-assembled on the theory that the original material would be realigned if undisturbed and the machine currently runs whisper quiet. The fan noise had become increasingly annoying over the last several months in a 4year old machine and doubtless will require repeating at some future time when I shall arm myself with one of the paste materials from the suggestions above.
On previous PCs that I've had to clean the processor cooling systems were fans atop the processors which could be cleaned in situ so the arrangement here was new to me. The face of the radiator was 70% clogged with dust and sorted with a trip to the shed to blast an air-line through from the rear.
The type of thing can be seen at the video time point below, albeit that in my case there were three coolant bars going to 2 different processors.
https://youtu.be/CBdYzJOnfAo?t=547

pgk

Michael Gilligan21/05/2022 06:02:53
avatar
20182 forum posts
1053 photos
Posted by pgk pgk on 21/05/2022 05:30:38:

[…]

The type of thing can be seen at the video time point below, albeit that in my case there were three coolant bars going to 2 different processors.
https://youtu.be/CBdYzJOnfAo?t=547

.

It’s not immediately obvious from that short video clip, so I will just mention that those are ‘Heat Pipes’

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

… and with a system like that, excellence of assembly is mandatory.

MichaelG.

.

https://support.lenovo.com/gb/en/solutions/pd027275-thermal-pipes-removal-and-installation-thinkpad-edge-e445

Edited By Michael Gilligan on 21/05/2022 06:25:03

SillyOldDuffer21/05/2022 08:49:05
Moderator
8691 forum posts
1967 photos
Posted by Michael Gilligan on 21/05/2022 06:02:53:
Posted by pgk pgk on 21/05/2022 05:30:38:

[…]

The type of thing can be seen at the video time point below, albeit that in my case there were three coolant bars going to 2 different processors.
https://youtu.be/CBdYzJOnfAo?t=547

.

It’s not immediately obvious from that short video clip, so I will just mention that those are ‘Heat Pipes’

**LINK**

...

Very educational this forum! Until this morning I assumed those Copper runs were just a simple metal conductor, used to transfer heat from a hot component such as a CPU across the circuit board to wherever it's mechanically convenient to mount a fan and radiator. Half right, now I know the pipe relies on latent heat and carries much more heat than a lump of Copper would.

Heat-sinks have always been a mystery to me: I know heat follows rules analogous to Ohms Law, but I've no idea how to design one. Big lump of Aluminium, with lots of fins, painted black, and don't assume it's earthed is the best I can do! How big and how many fins are just as wild guess.

Dave

Martin King 221/05/2022 08:51:40
1005 forum posts
450 photos

Any thoughts on the Zinc Oxide paste?

Cheers, Martin

Andy_G21/05/2022 09:30:11
avatar
173 forum posts
Posted by Martin King 2 on 21/05/2022 08:51:40:

Any thoughts on the Zinc Oxide paste?

Cheers, Martin

The original was almost certainly a silicone based 'heat sink' compound, something like this (which does contain zinc oxide).

https://cpc.farnell.com/servisol/200001000-25gm/heat-sink-compound-25g-tube/dp/SAHEATSINKCOMP

(Personally, I'd replace it with similar.)

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Support Our Partners
Eccentric July 5 2018
cowells
Dreweatts
Rapid RC
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest