Graphite as a thermal interface material? - Page 2

HighFlowRod · 06-26-2003, 09:50 PM

Quote:

Originally posted by Cathar
Yes, I know that this is the case, and it won't be anything like 2000WmK, more like 10-20WmK, but the question remains, "is that good enough"?

Would the resultant paste match, say, Arctic Silver for performance?

One way to find out. Heading off to buy some graphite lube and give it a burl.

burl - Aussie euphamism for trying to do something. Also an Aussie euphamism for driving a car as in "I'm goin' for a burl in me new car!"

Hey, Cathar. Mix the graphite with a little bit of toothpaste. Saw an article couple of months back that said toothpaste worked very well, but dries up very fast with the application of heat. Maybe the graphite would slow this effect.

Razor6 · 06-26-2003, 10:30 PM

What if those graphite sheets weren't used as a TIM but as a way of spreading the CPU's heat over a larger area with high efficiency. Attach the sheet to the bottom of a Cascade type block which has a much larger area of impingment. The additional thermal interface would be a problem though I suppose.

Since87 · 06-26-2003, 10:59 PM

Found a thread ranking thermal conductivities for TIM's.

Link. (Scroll down.)

It lists a couple graphite based products just above Arctic Silver. (Don't know which flavor of AS though.)

I'd be a bit concerned that graphite lube might have substantial electrical conductivity. Could be a real pain if you got it in the wrong place. I'd poke an Ohmeter into a glob of it.

utabintarbo · 06-27-2003, 07:39 AM

Quote:

Originally posted by Cathar
...

burl - Aussie euphamism for trying to do something. Also an Aussie euphamism for driving a car as in "I'm goin' for a burl in me new car!"

I thought you people spoke English down there!

Cathar · 06-27-2003, 08:18 AM

Quote:

Originally posted by utabintarbo
I thought you people spoke English down there!

LOL - it's actually derived from an old Scottish word, apparantly.

Well I got some graphite powder, and made up a paste, but didn't do ahead with it.

The graphite is not micronised enough. Sure it looks really fine to the eye, but it spreaded horribly on the CPU, and clumped together, and when on the super smooth surface of the CPU die, you could actually see each individual granule, and it was really "gritty" on a dry-mount.

I didn't have the balls to flip the power switch and potentially fry the CPU, it was that bad.

As a side thing though, I did try using some petroleum jelly (vaseline) as a thermal paste while I had the CPU out. I know it wouldn't last for long, but I was curious to try it.

Turns out to be bad news though. Well, not bad, but not good. Worked out to be about 3C worse than AS3 under load (T'bred B @ 2400MHz/1.85v running BurnK7).

Well I guess that shoots both the graphite and vaseline ideas in the foot.

hara · 06-27-2003, 08:41 AM

Try a drop of (distilled) water as TIM

leejsmith · 06-27-2003, 09:19 AM

so is the damond paste no good ?

Cossey3 · 06-27-2003, 09:35 AM

depends on how fine the diamonds are.

leejsmith · 06-27-2003, 09:49 AM

Synthetic diamond compounds or slurry can be used for rapid stock removal (90micron) to superfinishing (1/15 micron).
The formulation uses De Beers™ synthetic diamonds micronised into an octohedral shape for consistant long lasting cutting performance. All compounds are oil and water miscible and can be lubricated with RS diamond lubricant.
Suitable for use on Ferrous metals, Tungsten Carbide, Steel, Stainless steel, Glass, Synthetic and natural Precious stones.
All Syringes contain 5g of synthetic diamond.
Diamond compounds and Syringe labels are colour coded to enable grade recognition, the coarse grade being white (90 micron).
selection guide

would the 0- 1/15 micron one be ok ?

Since87 · 06-27-2003, 09:57 AM

One problem with diamond is that the particles are very rough and particles don't tend to get very good surface to surface contact with adjacent diamond particles.

Diamond grit has been tried before, but not with much success.

Cossey3 · 06-27-2003, 11:30 AM

where can you get that from coz it might te useful for lapping

leejsmith · 06-27-2003, 11:34 AM

from rs coponents.

www.rswww.com

that is what is supposed to be used for.

go to mechanical then abrasives , lapping.

bigben2k · 06-27-2003, 11:35 AM

Quote:

Originally posted by Since87
Found a thread ranking thermal conductivities for TIM's.

Link. (Scroll down.)

It lists a couple graphite based products just above Arctic Silver. (Don't know which flavor of AS though.)

I'd be a bit concerned that graphite lube might have substantial electrical conductivity. Could be a real pain if you got it in the wrong place. I'd poke an Ohmeter into a glob of it.

Good link!

I think I'd also stick to lapping, with that diamond stuff.

Cossey3 · 06-27-2003, 11:50 AM

the diamond stuff is looking very interesting for lapping as 1200 grade paper has 16 micron particles and p2500 has 6 micron so lapping down to 1/2 or even 1/15 micron should give good results

Tuff · 06-27-2003, 01:08 PM

I thought that graphite was discussed earlier??? We found that the properties for heat transfer were too linear...ie...way better one way than the other???

Tuff

Volenti · 06-27-2003, 09:17 PM

Cathar, give blu-tack a try, I havn't personally used it on the cpu, but I have used it on my southbridge heatsink (nforce2) and vidcard ramsinks, seems to conduct heat pretty well, may suprise you.

06-27-2003, 08:41 AM	#31
hara Cooling Savant Join Date: Oct 2002 Location: Malta, Mediterranean Posts: 662	Try a drop of (distilled) water as TIM __________________ - Every great HD crash day is the day before back-up day. - My Past System - "Better to reign in Hell than serve in Heaven." - Milton, Paradise Lost. - FMZ

06-27-2003, 09:17 PM	#41
Volenti Cooling Savant Join Date: Jan 2002 Location: in a nice cool spot Posts: 427	Cathar, give blu-tack a try, I havn't personally used it on the cpu, but I have used it on my southbridge heatsink (nforce2) and vidcard ramsinks, seems to conduct heat pretty well, may suprise you. __________________ feel free to icq/msn me, I'm always willing to toss around ideas.

06-26-2003, 10:30 PM	#27
Razor6 Cooling Savant Join Date: Apr 2002 Location: Houston, TX Posts: 192	What if those graphite sheets weren't used as a TIM but as a way of spreading the CPU's heat over a larger area with high efficiency. Attach the sheet to the bottom of a Cascade type block which has a much larger area of impingment. The additional thermal interface would be a problem though I suppose.

06-26-2003, 10:59 PM	#28
Since87 Pro/Guru - Uber Mod Join Date: Sep 2002 Location: Indiana Posts: 834	Found a thread ranking thermal conductivities for TIM's. Link. (Scroll down.) It lists a couple graphite based products just above Arctic Silver. (Don't know which flavor of AS though.) I'd be a bit concerned that graphite lube might have substantial electrical conductivity. Could be a real pain if you got it in the wrong place. I'd poke an Ohmeter into a glob of it.

06-27-2003, 09:19 AM	#32
leejsmith Cooling Savant Join Date: Mar 2003 Location: notts uk Posts: 408	so is the damond paste no good ?

06-27-2003, 09:35 AM	#33
Cossey3 Cooling Neophyte Join Date: Jun 2003 Location: South London, UK Posts: 62	depends on how fine the diamonds are.

06-27-2003, 09:49 AM	#34
leejsmith Cooling Savant Join Date: Mar 2003 Location: notts uk Posts: 408	Synthetic diamond compounds or slurry can be used for rapid stock removal (90micron) to superfinishing (1/15 micron). The formulation uses De Beers™ synthetic diamonds micronised into an octohedral shape for consistant long lasting cutting performance. All compounds are oil and water miscible and can be lubricated with RS diamond lubricant. Suitable for use on Ferrous metals, Tungsten Carbide, Steel, Stainless steel, Glass, Synthetic and natural Precious stones. All Syringes contain 5g of synthetic diamond. Diamond compounds and Syringe labels are colour coded to enable grade recognition, the coarse grade being white (90 micron). selection guide would the 0- 1/15 micron one be ok ?

06-27-2003, 09:57 AM	#35
Since87 Pro/Guru - Uber Mod Join Date: Sep 2002 Location: Indiana Posts: 834	One problem with diamond is that the particles are very rough and particles don't tend to get very good surface to surface contact with adjacent diamond particles. Diamond grit has been tried before, but not with much success.

06-27-2003, 11:30 AM	#36
Cossey3 Cooling Neophyte Join Date: Jun 2003 Location: South London, UK Posts: 62	where can you get that from coz it might te useful for lapping

06-27-2003, 11:34 AM	#37
leejsmith Cooling Savant Join Date: Mar 2003 Location: notts uk Posts: 408	from rs coponents. www.rswww.com that is what is supposed to be used for. go to mechanical then abrasives , lapping.

06-27-2003, 11:50 AM	#39
Cossey3 Cooling Neophyte Join Date: Jun 2003 Location: South London, UK Posts: 62	the diamond stuff is looking very interesting for lapping as 1200 grade paper has 16 micron particles and p2500 has 6 micron so lapping down to 1/2 or even 1/15 micron should give good results

06-27-2003, 01:08 PM	#40
Tuff Cooling Savant Join Date: Feb 2003 Location: Canada Posts: 141	I thought that graphite was discussed earlier??? We found that the properties for heat transfer were too linear...ie...way better one way than the other??? Tuff

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