Author Topic: Thermal compound recomendations  (Read 852 times)

Gattopardo

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Thermal compound recomendations
« on: December 22, 2018, 03:11:53 pm »
Have finally finished my 120ml tube of rs thermal compound.

So what would you recommend as an easy to apply/smear thermal stuff?  Are the pads any good?  Are the figures quoted for heat transfer relevant?


Filled with indecision

Kim

  • Timelord
Re: Thermal compound recomendations
« Reply #1 on: December 22, 2018, 03:37:53 pm »
I reckon the most important thing is not to use the glue type thinking it's the paste type (DAHIKT).
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Gattopardo

  • Lord of the sith
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Re: Thermal compound recomendations
« Reply #2 on: December 22, 2018, 03:56:40 pm »
I reckon the most important thing is not to use the glue type thinking it's the paste type (DAHIKT).

There is a glue? 

Kim

  • Timelord
Re: Thermal compound recomendations
« Reply #3 on: December 22, 2018, 03:59:05 pm »
I reckon the most important thing is not to use the glue type thinking it's the paste type (DAHIKT).

There is a glue?

Oh yes.  Commonly used on things that are Not Computers.
To ride the Windcheetah, first, you must embrace the cantilever...

Gattopardo

  • Lord of the sith
  • Overseaing the building of the death star
Re: Thermal compound recomendations
« Reply #4 on: December 22, 2018, 04:10:35 pm »
https://uk.rs-online.com/web/p/thermal-grease/0554311/ is the stuff i have just finished.

How about thermal interface material cut to size?  Currently am reseating cpus and gpus

Re: Thermal compound recomendations
« Reply #5 on: December 23, 2018, 10:13:01 am »
I used to use Artic Silver paste when I did a fair bit of messing around with this kind of stuff. Always worked well and cleans off easily with TIM cleaner or the like if you need to swap heat sinks.
I think you'll find it's a bit more complicated than that.

Gattopardo

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Re: Thermal compound recomendations
« Reply #6 on: December 25, 2018, 07:53:52 pm »
I used to use Artic Silver paste when I did a fair bit of messing around with this kind of stuff. Always worked well and cleans off easily with TIM cleaner or the like if you need to swap heat sinks.

Is artic silver electrically conductive?

Am looking at the thermal conductivity and a higher figure means that things should be better...or is it that after a certain point the figure doesn't matter.  Am so indecisive..

Valiant

  • aka Sam
    • Radiance Audio
Re: Thermal compound recomendations
« Reply #7 on: January 04, 2019, 10:38:22 am »
I used to use Arctic silver too. What are you using it on?
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Re: Thermal compound recomendations
« Reply #8 on: January 04, 2019, 11:10:37 am »
I used to use Artic Silver paste when I did a fair bit of messing around with this kind of stuff. Always worked well and cleans off easily with TIM cleaner or the like if you need to swap heat sinks.

Is artic silver electrically conductive?


No but apparently it is slightly capacitive so they recommend keeping it away from exposed traces or pins.
I think you'll find it's a bit more complicated than that.

Gattopardo

  • Lord of the sith
  • Overseaing the building of the death star
Re: Thermal compound recomendations
« Reply #9 on: January 06, 2019, 04:29:32 pm »
After spending far too much time looking it to thermal compounds, they are used in in electrical vehicles so data sheets are very very important.   The best is a Dow corning compound.

Computer wise the compound doesn't really matter, as long as it's there.  The heatsink and fans do more...

Re: Thermal compound recomendations
« Reply #10 on: January 07, 2019, 08:05:30 am »
And use less rather than .more.. the objective is to just fill surface air voids.

gibbo

  • Riding for fun, cake and beer.
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Re: Thermal compound recomendations
« Reply #11 on: January 08, 2019, 08:24:45 am »
https://uk.rs-online.com/web/p/thermal-grease/0554311/ is the stuff i have just finished.

How about thermal interface material cut to size?  Currently am reseating cpus and gpus

I used to spec a Fujipoly material in the fibre optic transceivers I'd design as we didn't like the "wet" process of the paste plus they had to be aqueous washable. As I recall correctly one could get quite high thermal conductivities (11W/mk) but thermal transfer and pressure of the contact surfaces is directly related to good (or bad) thermal transfer meaning you need to spec the right thickness and try and work out how much compression you need to apply which affects the overall height of the assembly which may or may not be important to you.

A very quick glance on RS comparing thermal conductivity of pads and paste show they are very similar.

If your CPU etc was originally fitted with thermal paste then I'd probably stick with that.

Gibbo.


Gattopardo

  • Lord of the sith
  • Overseaing the building of the death star
Re: Thermal compound recomendations
« Reply #12 on: January 08, 2019, 01:02:43 pm »
And use less rather than .more.. the objective is to just fill surface air voids.

That is why I never used the pea method, just the used credit card method to pass the compound around the area of the cpu's and the heatsink.


Gattopardo

  • Lord of the sith
  • Overseaing the building of the death star
Re: Thermal compound recomendations
« Reply #13 on: January 08, 2019, 01:05:55 pm »
https://uk.rs-online.com/web/p/thermal-grease/0554311/ is the stuff i have just finished.

How about thermal interface material cut to size?  Currently am reseating cpus and gpus

I used to spec a Fujipoly material in the fibre optic transceivers I'd design as we didn't like the "wet" process of the paste plus they had to be aqueous washable. As I recall correctly one could get quite high thermal conductivities (11W/mk) but thermal transfer and pressure of the contact surfaces is directly related to good (or bad) thermal transfer meaning you need to spec the right thickness and try and work out how much compression you need to apply which affects the overall height of the assembly which may or may not be important to you.

A very quick glance on RS comparing thermal conductivity of pads and paste show they are very similar.

If your CPU etc was originally fitted with thermal paste then I'd probably stick with that.

Gibbo.

Sort have thought the thickness would sort it self out under pressure.  Would pads be better id a little more pressure was required, such as an xbox/ps3 cpu/gpu

gibbo

  • Riding for fun, cake and beer.
    • Boxford Bike Club
Re: Thermal compound recomendations
« Reply #14 on: January 08, 2019, 03:04:11 pm »

Sort have thought the thickness would sort it self out under pressure.
 

Yes, up to a point but you don't want to over stress things. If headroom's not an issue then it probably doesn't matter which solution you go for. If it is and you're squeezing everything too tightly because the material won't compress down enough then you may be adversely stressing the PCB and CPU which, worst case, could cause a failure.

I've used mats that effectively don't compress at all whereas some of the pad materials compress across a wide range. In general, based on my experience, the highly compressible/soft materials have lower conductivity whereas the high conductivity ones are more dense therefore comparatively don't compress much at all. Fujipoly Xr-m (I think) has a high conductivity and comes in different thicknesses and compresses down to something like 50% of the original thickness.

Quote
Would pads be better id a little more pressure was required, such as an xbox/ps3 cpu/gpu

Pads would work but you'd need the stuff with higher conductivity than paste otherwise there's not much point IMO. No experience of Xbox/ PS3 apart from watching my son kill people on Grand Theft Auto.

Gibbo.




Gattopardo

  • Lord of the sith
  • Overseaing the building of the death star
Re: Thermal compound recomendations
« Reply #15 on: January 09, 2019, 01:13:38 pm »
Took apart a laptop to clear the fluff filled fans and replace the heatpaste....and there are a few pads too.


FFS.