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Thermal Pad & Paste Removal and Application

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9mmCensor

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Oct 23, 2003
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A Guide to Thermal Pad & Paste Removal and Application
So here is a guide to tell all(mostly) about TIM .

ABC's of Themal Stuff.
Thermal Interface Material (TIM) - This is the stuff (a paste or a 'pad') that helps conduct heat from your CPU's die or IHS to the heatsink.
IHS - Integrated HeatSpreader, these are the things seated on your CPU (Pentium 4's and the A64 family has them) that spread the heat around, and are primarily used to prevent damage to the die.
Die - This is the actual CPU's main area, it is situated in the middle of the CPU and is a quadrangle (4 sided). This is where the heat comes from.

Important Links:
OC.com's TIM Removal Guide - Read this to find out how to remove the TIM
Arctic Silvers Application Guide - Read this to find out how to apply the TIM
OC.com's Lapping Guide - Read this to find out how to lap a heatsink or waterblock.
Lapping Kits - Easy PC Kits - The best there is.
Make sure you get whats advertised!

Common Solvents:
Carberator Cleaner - Very Good, non damaging.
PURE Acetone - Very good, very strong, potentially damaging to the CPU (not the die though), so take care when using acetone.
Xylene based (Goof Off - NOT Goo Off) - Good.
Nail Polish Remover - BAD. BAD. IT has oils that will hurt preformance (thermally), BAD - DO NOT USE.
Isopropyl Alcohol - The stronger the better it will remove it, be careful though.
WD-40 - BAD. Leaves trace oil residue.
ArctiClean - Great stuff. More expensive than other things though.

FAQ:
"How do I remove the thermalpad/AS"
Read the link provided, it does a VERY good job of imforming you of this (OK mabey I am a little biased)

"How do I apply AS5"
Read the link provided.

"Do I need to lap my heatsink or waterblock?"
If it has had some previous TIM on it, especially the stock stuff, yes you should. You dont have to, but it will hamper preformance slightly.

"How thick should the layer of TIM be?"
Thin, as thin as possible, while still completely covering the die.

"Which method traditional (user spreads it) or the new "rice grain" style where the pressure of the heatsink spreads the TIM around.
This has yet to be concluded with any certainty. But the current belief is that for CPU's with Heatspreaders there is no difference, but for application to the actual die, then the tradition method is best.

"I lapped my heatsink/waterblock, and now its like a mirror, it must be super flat now."
Is a ball bearing shinney? (yes) Is it flat? (no).

"Oh my gosh! I changed thermal paste and my temps when up/down 10 degrees Celcius!"
In short motherboard temperature sensors sensors are not good, and there are many factors that can change (ambient temp being a big one) that could lead to these results. They are most likely misleading.

Optimal Temps of Common Pastes
AS5 -> Long-Term: –50°C to 130°C (> 180°C Peak)
Ceramique -> Long-Term: –150°C to 125°C (> 180°C Peak)
AS Alumina - Long-Term: – 40°C to >180°C

Picking a paste that is suited for your application is important to achieve optimal results. This is more important for temps less than zero, as temps should not get as high as the max for these pastes. Therefore when using phase change or other extreme coolers (LN2, Dry Ice) consider the temperature your cooler will be running an pick a paste to suit it.


Next up:
Settling Time


PM me if you have anything to add.
- 9mmCensor
 
Last edited:
w00t! Thanks for reading this. Most people tend to simply start a new thread, whos questions have been anwsered already.
 
I have a few thoughts/questions about lapping...
I have a manufacturing degree so I know a little about surface roughness and surface flatness, which are two different things of course. I'm assuming both a smoother and a more flat surface contribute to better cooling performance (to some degree at least).
Surface roughness is relatively easy to measure, by using a comparator guide. However surface flatness is relatively difficult to measure and even more difficult to acheive. Manufactures spend thousands of dollars on flat granite surfaces from which precision measurements can be achieved. Flatness is generally measured using an optical flat. So getting to the point. You're doing your lapping on your flat (glass) surface or whatever. It's easy to see that that surface is smooth, but you don't actually know it's flat.
I'm wondering how much trouble heatsink manufacturers go through to make sure their heatsinks are smooth and flat, and what the possibility may be that by lapping one could produce a smooth, but not flat surface, that does not perform as well. Could this possibly be a concern or am I just paranoid? It seems that most people get good results from (careful) lapping, so why not, right?
I wish I had access to the proper metrology tools...it would be interesting to see how flat my heatsink actually is...
 
Thanks so much for the links, I overlooked that article...

The "Precision Lapping" article is rather interesting, and I agree with just about everything in there, but I'm primarily concerned with zonal error as referred to in the article. If you don't have the metrology tools, you can't actually tell how flat the surface is before you lap and after you lapped it. The only measurement (presumed) taken is that of cooling performance before and after, which of course requires taking the time to install the heatsink.
There are just a lot of variables that the article didn't really asses. Like the fact that hand sanding isn't a precision operation and would seem to be rather prone to zonal error...human randomness or not. Anway...I'm just rambling for my own entertainment really...there is really no debate. Cooling performance is, in the end, what matters...
 
do we want to add some facts about cpu temps? those seem really common too.
 
I also have a question on lapping. My question is I see the theory behind lapping yet doing this seems to entirly disregard the point of artic silver 5? I thought the point of AS5 was to go in thoughs wholes fill them and tranfser the heat. I know AS5 does not carry all the heat, but I would think a few small pore tip holes on your HS would be good, becouse then AS5 could get up in them and kind of form a plug type thing insted of just another surface between the CPU and HS. I know I am wrong on this or else lapping would not work. My question is why does lapping work better then AS5?
 
Lapping doesn't work better than AS5, it works in conjunction with AS5 and yields better temps than that same unlapped heatsink in conjunction with AS5. You're right, the point of TIM's like AS5 is to fill the holes in the heatsink surface, but the holes being referred to are microscopic. In other words, a simple lap job with sandpaper isn't going to smooth out all the holes, but it will smooth out some of the larger valleys and peaks on the heatsink surface. This maximizes the contact are between the CPU and the heatsink, which lowers temps.
 
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