gold leaf as thermal interface material?

Ewan · 08-13-2003, 04:05 PM

My curiousity has got the better of me and this is my first post and question.

I think the thermal interface goo is no good and I can't see a way of getting round it. Applying more pressure seems to help.
Anyway, has anyone tried gold leaf? It's incredibly thin and soft so it may be able to do the trick. I'm concerned that air may get trapped in pockets if it's not applied well but the thermal conductivity and miniscule thickness may be able to make up for it. Will it be soft enough to get into cracks if enough pressure is applied?

Has anyone tried it?

joemac · 08-13-2003, 04:09 PM

What is the price of a gold leaf? Can gold be mixed with a "goo" like silver does? Is a gold leaf really gold and where could I get some?

MoNk · 08-13-2003, 05:16 PM

Gold leaf is very cheap because it is extremely thin. You can buy it from cake decorating stores, possibly some sweet shops (probably not). I should have saved some last time I ate it.
This is something I'm going to give a go. Good idea

I wonder if anyone has tried this before...

Googles....

http://www2b.abc.net.au/science/scri...opic46218.shtm

http://www.dansdata.com/a7v2.htm (mentions using gold leaf to unlock a cpu)

http://forums.procooling.com/vbb/sho...&threadid=7095 (gareth mentions using it in this thread here at PC)

Few more here, http://forums.procooling.com/vbb/sea...der=descending

joemac · 08-13-2003, 07:05 PM

you know MoNk it does sound it is a good idea. Please let us know what your results are.

Cathar · 08-13-2003, 10:23 PM

Be very careful.

The "cheap" gold leaf is really imitation gold leaf, and is not want you want. I'm not sure what it's made out of, and it does have some non-metal material in it that holds it together. It could be as effective as putting a (very) thin sheet of plastic between the CPU and the heatsink.

A sheet of real pure gold leaf (A4 or US letter size) can cost upwards of $40US.

I investigated this a while back, but didn't have the gumption to front $40US for a sheet of the real stuff.

Arcturius · 08-13-2003, 11:39 PM

You should be able to get it cheap from a chemical supply company--my High School Chemistry teacher had a little 'booklet' of the stuff, about the size of a pack of Post-Its. It had lots of gold leaves, separated by something like tissue paper.

He said it was dirt cheap, since the entire booklet only contained a tiny fraction of an ounce of gold (less than 1/100th, if I'm not mistaken)

cybrsamurai · 08-14-2003, 12:12 AM

Or try an art supply store. You can get real gold leaf for not alot of money.

winewood · 08-14-2003, 12:16 AM

Question: how would you get the foil stuff to squish down into the depressions and malformations if you just place it over the core? With goo, you know it will be compacted and gel into the cracks when you compress it with the block...

mhayenga · 08-14-2003, 01:34 AM

sorry if I'm wrong... but doesnt gold have less thermal conductivity than silver, copper, and aluminum? Just wondering why not "silver leaf"

Ewan · 08-14-2003, 01:49 AM

Quote:

how would you get the foil stuff to squish down into the depressions and malformations if you just place it over the core? With goo, you know it will be compacted and gel into the cracks when you compress it with the block...

Well, that's the thing. I don't know and I want to know if anyone has tried this. It sound to me like Cathars gold leaf was not the proper stuff since $40 is way to much for gold leaf. I doubt it's that much more expensive than aluminium foil.

Heat transfer is a proportional to surface area and inversely proportional to thickness. Not filling in all the cracks reduces the surface area and will reduce heat tranfer by a percentage of the lost area. I.e. if you only get half the contact area you get half the heat transfer (or double the temperature difference). I doubt that gold leaf will do as good a job of filling in cracks as goo, but I don't think it will need to because the thermal conductivity is so good. Even if the surface area is only a 50th of what it is with goo, the incredible difference in thermal conductivity should be able to make up for this.
And then we have the thickness. If the gold leaf interface is a 10th of the thickness of goo (which I think should be doable in most cases) the heat transfer will be 10 times better.

However I think that greater than average pressures will be required. It would be good if Cathar could try this since I noticed in another thread that you apply a lot more than the recommended pressure.

Heat would also help in settling the gold leaf. Running the CPU for a short period with the fan slowed down so that it runs for a minute or 2 at ca 75C would make the gold leaf marginaly softer and hopefully seat it better.

pippin88 · 08-14-2003, 03:41 AM

Ewan I think you have a few things mixed up. Gold is much less thermally conductive than either copper or silver. The only reason to use it for this application would be that it is very thin and very maleable.

Boli · 08-14-2003, 07:25 AM

You CAN get silver leaf you know... we had some of that in chemistry (or physics can't remember.. but we still got hold of some).

Ewan · 08-14-2003, 08:20 AM

No, I don't have anything mixed up. I was comparing the thermal conductivity of Gold to thermal goo, not copper or silver. Arctic silver 3 has a conductivity of around 10 W/mK whereas gold is about 300. That's a 30 fold difference (not quite the 50 fold difference that I mentioned above).

I didn't know silver foil was available. That might be a good bet as well.

ezlid · 08-14-2003, 10:45 AM

FYI

Out of curiosity I Googled "silver leaf" and hit this site which sells various metal leafs (?): Here

One thing thing I saw is the imitation gold leaf, mentioned by Cathar in an earlier reply, made of 85% copper and 15% zinc. They also have copper and silver leaf as well, although the copper leaf is not available.

Also found this site Gold/Silver Leaf that sells gold leaf by the sheet, 3.25" X 3.25" for $5.75 and silver for $16.50 for a book of 25 sheets.

Srill curious.

pippin88 · 08-15-2003, 08:20 AM

Quote:

Originally posted by Ewan
No, I don't have anything mixed up. I was comparing the thermal conductivity of Gold to thermal goo, not copper or silver. Arctic silver 3 has a conductivity of around 10 W/mK whereas gold is about 300. That's a 30 fold difference (not quite the 50 fold difference that I mentioned above).

I didn't know silver foil was available. That might be a good bet as well.

Ok, sorry.

Bit disapopinting to hear the thermal conductivity of the pastes are so low though.

Ewan · 08-15-2003, 09:19 AM

Quote:

Bit disapopinting to hear the thermal conductivity of the pastes are so low though.

Don't be dissappointed. It means there's lots of room for improvement!

Brians256 · 08-15-2003, 10:47 AM

Well, someone (was it #Rotor?) tried using a very malleable metal and it didn't work well. No, I don't remember what it was, but I'm sure that the collective Pro/Forum consciousness does. Just because it is very malleable/ductile does not mean that it will work well.

I still want to see the wonder-goop that the New York university created (was it Buffalo New York?).

BO(V)BZ · 08-15-2003, 01:19 PM

You could try a phase-change material like what Thermagon makes. That's probably what you are thinking of Brians. It has about double the thermal conductivity of normal paste. It's basically a thin piece of metal, which melts at 60*C and fills all the little spaces on your processor and heatsink / WB. I've got a sample, but haven't actually put it to any real use yet.

BO(V)BZ

Brians256 · 08-15-2003, 01:42 PM

Well, it was definitely phase change, but not in the sense that many people think of. AMD and Intel use that term phase-change for their pad of thermal goo that melts when the CPU runs and then stiffens up.

I think it was Indium metal, but I'm not sure. It wasn't a brand name product. That I do remember.

AXDA2600DKV3D · 08-15-2003, 01:44 PM

im starting to count my pennies and im kinda thinking about getting some of that silver leaf for a try, ill wait till i get my new temp sensors in

Gareth · 08-17-2003, 12:39 PM

Quote:

Originally posted by winewood
Question: how would you get the foil stuff to squish down into the depressions and malformations if you just place it over the core? With goo, you know it will be compacted and gel into the cracks when you compress it with the block...

My girlfriend has just finished a hnd in media make-up, for part of her final project she did a photo shoot where gold leaf was used (on me), it is very easy to get it very flat. the best way is to use a very thin layer of glue (can be sprayed on) and then use a fine brush get rid of any imperfections.

08-13-2003, 04:05 PM	#1
Ewan Cooling Neophyte Join Date: Jun 2003 Location: Sweden Posts: 30	gold leaf as thermal interface material? My curiousity has got the better of me and this is my first post and question. I think the thermal interface goo is no good and I can't see a way of getting round it. Applying more pressure seems to help. Anyway, has anyone tried gold leaf? It's incredibly thin and soft so it may be able to do the trick. I'm concerned that air may get trapped in pockets if it's not applied well but the thermal conductivity and miniscule thickness may be able to make up for it. Will it be soft enough to get into cracks if enough pressure is applied? Has anyone tried it?

08-14-2003, 12:12 AM	#7
cybrsamurai Cooling Savant Join Date: Jan 2002 Location: Ashland Posts: 296	Or try an art supply store. You can get real gold leaf for not alot of money. __________________ Air cooled my ass.

08-14-2003, 12:16 AM	#8
winewood Cooling Savant Join Date: Nov 2002 Location: in my chair Posts: 574	Question: how would you get the foil stuff to squish down into the depressions and malformations if you just place it over the core? With goo, you know it will be compacted and gel into the cracks when you compress it with the block... __________________ -winewood-

08-13-2003, 04:09 PM	#2
joemac Cooling Savant Join Date: Dec 2002 Location: Dallas Posts: 339	What is the price of a gold leaf? Can gold be mixed with a "goo" like silver does? Is a gold leaf really gold and where could I get some?

08-13-2003, 05:16 PM	#3
MoNk Cooling Neophyte Join Date: Apr 2003 Location: New Zealand Posts: 3	Gold leaf is very cheap because it is extremely thin. You can buy it from cake decorating stores, possibly some sweet shops (probably not). I should have saved some last time I ate it. This is something I'm going to give a go. Good idea I wonder if anyone has tried this before... Googles.... http://www2b.abc.net.au/science/scri...opic46218.shtm http://www.dansdata.com/a7v2.htm (mentions using gold leaf to unlock a cpu) http://forums.procooling.com/vbb/sho...&threadid=7095 (gareth mentions using it in this thread here at PC) Few more here, http://forums.procooling.com/vbb/sea...der=descending

08-13-2003, 07:05 PM	#4
joemac Cooling Savant Join Date: Dec 2002 Location: Dallas Posts: 339	you know MoNk it does sound it is a good idea. Please let us know what your results are.

08-13-2003, 10:23 PM	#5
Cathar Thermophile Join Date: Sep 2002 Location: Melbourne, Australia Posts: 2,538	Be very careful. The "cheap" gold leaf is really imitation gold leaf, and is not want you want. I'm not sure what it's made out of, and it does have some non-metal material in it that holds it together. It could be as effective as putting a (very) thin sheet of plastic between the CPU and the heatsink. A sheet of real pure gold leaf (A4 or US letter size) can cost upwards of $40US. I investigated this a while back, but didn't have the gumption to front $40US for a sheet of the real stuff.

08-13-2003, 11:39 PM	#6
Arcturius Cooling Savant Join Date: Aug 2001 Location: Chippewa Falls, Wisconsin Posts: 294	You should be able to get it cheap from a chemical supply company--my High School Chemistry teacher had a little 'booklet' of the stuff, about the size of a pack of Post-Its. It had lots of gold leaves, separated by something like tissue paper. He said it was dirt cheap, since the entire booklet only contained a tiny fraction of an ounce of gold (less than 1/100th, if I'm not mistaken)

08-14-2003, 01:34 AM	#9
mhayenga Cooling Neophyte Join Date: May 2002 Location: Earth Posts: 46	sorry if I'm wrong... but doesnt gold have less thermal conductivity than silver, copper, and aluminum? Just wondering why not "silver leaf"

08-14-2003, 03:41 AM	#11
pippin88 Cooling Savant Join Date: Oct 2002 Location: Australia Posts: 285	Ewan I think you have a few things mixed up. Gold is much less thermally conductive than either copper or silver. The only reason to use it for this application would be that it is very thin and very maleable.

08-14-2003, 07:25 AM	#12
Boli Cooling Savant Join Date: Apr 2003 Location: Blackburn / Dundee Posts: 451	You CAN get silver leaf you know... we had some of that in chemistry (or physics can't remember.. but we still got hold of some).

08-14-2003, 08:20 AM	#13
Ewan Cooling Neophyte Join Date: Jun 2003 Location: Sweden Posts: 30	No, I don't have anything mixed up. I was comparing the thermal conductivity of Gold to thermal goo, not copper or silver. Arctic silver 3 has a conductivity of around 10 W/mK whereas gold is about 300. That's a 30 fold difference (not quite the 50 fold difference that I mentioned above). I didn't know silver foil was available. That might be a good bet as well.

08-14-2003, 10:45 AM	#14
ezlid Cooling Neophyte Join Date: Sep 2001 Location: Houston, TX Posts: 55	FYI Out of curiosity I Googled "silver leaf" and hit this site which sells various metal leafs (?): Here One thing thing I saw is the imitation gold leaf, mentioned by Cathar in an earlier reply, made of 85% copper and 15% zinc. They also have copper and silver leaf as well, although the copper leaf is not available. Also found this site Gold/Silver Leaf that sells gold leaf by the sheet, 3.25" X 3.25" for $5.75 and silver for $16.50 for a book of 25 sheets. Srill curious.

08-15-2003, 10:47 AM	#17
Brians256 Pro/Staff Join Date: Oct 2001 Location: Klamath Falls, OR Posts: 1,439	Well, someone (was it #Rotor?) tried using a very malleable metal and it didn't work well. No, I don't remember what it was, but I'm sure that the collective Pro/Forum consciousness does. Just because it is very malleable/ductile does not mean that it will work well. I still want to see the wonder-goop that the New York university created (was it Buffalo New York?).

08-15-2003, 01:19 PM	#18
BO(V)BZ Cooling Neophyte Join Date: Apr 2003 Location: WI Posts: 53	You could try a phase-change material like what Thermagon makes. That's probably what you are thinking of Brians. It has about double the thermal conductivity of normal paste. It's basically a thin piece of metal, which melts at 60*C and fills all the little spaces on your processor and heatsink / WB. I've got a sample, but haven't actually put it to any real use yet. BO(V)BZ

08-15-2003, 01:42 PM	#19
Brians256 Pro/Staff Join Date: Oct 2001 Location: Klamath Falls, OR Posts: 1,439	Well, it was definitely phase change, but not in the sense that many people think of. AMD and Intel use that term phase-change for their pad of thermal goo that melts when the CPU runs and then stiffens up. I think it was Indium metal, but I'm not sure. It wasn't a brand name product. That I do remember.

08-15-2003, 01:44 PM	#20
AXDA2600DKV3D Cooling Neophyte Join Date: Aug 2003 Location: Florida, USA Posts: 40	im starting to count my pennies and im kinda thinking about getting some of that silver leaf for a try, ill wait till i get my new temp sensors in

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