Risks for using too much thermal paste?

[courtney01]

I'm removing intel's stock thermal pad and using OCZ freeze instead. I'm also applying it on the IHS using the "single grain of rice in the center and squash it with the HSF" method. If I happen to put too much in the center and excess paste squeezes out, is that bad for the computer? I'm told OCZ freeze is supposed to be non conducting and non capacitive, but I don't know how that would apply here.

On a related note, when I handle intel's HSF, I know I'm not supposed to touch the copper colored disk, but am I allowed to touch the large, silver metal part that looks like a fan?

I'm also using 91% isopropyl alcohol to clean off old paste. When I do this, I try to stay on the copper colored disk in the center, but sometimes the alcohol or paste get onto the silver metal part, so I have to clean that part, too. Is it bad to clean or get alcohol or paste on that part?

 

[criccio]

First off, the downside to to much TIM is easy, you will get higher temps. Secondly, if the TIM is non-conductive, then by design it should be alright if a little is on the PCB. You should clean as much off as you can though. Isopropyl alcohol is completely non-conductive so thats fine.

 

[Menelmarar]

1. If you use a single grain of rice sized dot, it will not squeeze out from under the heatsink.

Heatsink compound is not as good a conductor as metal, though it's better than air. You want just enough to fill in the air gaps in the micro imperfections of the heatsink and top of the IHS. Any more than that small amount and you loose thermal transfer efficiency.

2. Arctic Silver has some nice instructions. Obviously it's intented for their paste, but I imagine it's good universally. http://www.arcticsilver.com/arctic_silver_instructions.htm

3. Your not supposed to touch the copper colored disk, as your fingers have oils and such that could contaminate the surface and reduce cooling efficiency. The copper disk is round, the IHS is square, some of the aluminum of the heatsink will mate with the CPU IHS, thus you don't want contaminates there either. Just clean it well with the alcohol you have, give it a little to make sure it's dry and press it down and mount it. Hold it by the sides, there is no reason to touch the bottom, either the copper disk or the aluminum part either.

Alcohol will not hurt aluminum

 

[Riccochet]

Better to have slightly more than needed than not enough.

Blob in the middle method is what I use mostly. Expermient with it to get that "right" amount.

 

[GJSNeptune]

Too much thermal grease will insulate. All the thermal grease is suppose to do is fill in microscopic gaps to optimize heat transfer.

When handling the HSF, avoid the copper. You can hold onto the fan, but touch the aluminum/silver as little as possible just to be safe from skin oils and such.

The alcohol won't hurt anything. That's why we use it to clean. It dries quickly. If any grease gets on the aluminum/silver, simply clean it off with the isopropyl.

 

[courtney01]

Wow so many helpful advices, thanks!

if the TIM is non-conductive, then by design it should be alright if a little is on the PCB. You should clean as much off as you can though. Isopropyl alcohol is completely non-conductive so thats fine.

Is the PCB the motherboard surface?

If a little bit squeezes out beyond the copper disk and into the aluminum part, is that ok?

I'm not worried about putting too much paste actually, but the last time I took off my HSF to see how it spread after some computer use, the spreading was a bit uneven (I put a small dot in the center, but I do remember that I couldn't cleanly "cut off" the thread of paste as I was pulling away, so a tail piece might have made it a bit lopsided). On one side, it almost spread to the very edge of the IHS but on the other it was a normal, safe distance. So I'm just worried that even though I don't put a lot, it might spread asymmetrically so that the paste might squeeze out on one side.

The copper disk is round, the IHS is square, some of the aluminum of the heatsink will mate with the CPU IHS, thus you don't want contaminates there either. Just clean it well with the alcohol you have, give it a little to make sure it's dry and press it down and mount it. Hold it by the sides, there is no reason to touch the bottom, either the copper disk or the aluminum part either.

So even though the copper disk is slightly raised from the aluminum face, the aluminum face still touches the IHS?

When handling the HSF, avoid the copper. You can hold onto the fan, but touch the aluminum/silver as little as possible just to be safe from skin oils and such.

I was paranoid, so I pretty much handled the HSF by holding the plastic parts only, but I accidentally touched the sides of the aluminum part occasionally and got worried. So now I know that I just need to clean it off with alcohol.

By the way, I used q-tips and toilet paper to clean and dry the IHS and copper disk. Is this bad? And I noticed that I could never make the surfaces completely shiny and clean. Is it bad to have even invisible residues from the paste left on the surfaces before applying fresh paste?

 

[Menelmarar]

So even though the copper disk is slightly raised from the aluminum face, the aluminum face still touches the IHS?

When I said that, I was picturing and old schooll copper core heatsink that was flush, kinda like this guy:
http://img.tomshardware.com/us/2003/09/17/three_red/amd_3200_bottom.jpg

Common sense, just look and see, you can touch anythingthing that isn't mating to the CPU.

 

[GJSNeptune]

Q-Tips are pretty good to use, but I wouldn't use toilet paper, as it breaks apart easily and is very linty.

 

[Zero82z]

By the way, I used q-tips and toilet paper to clean and dry the IHS and copper disk. Is this bad? And I noticed that I could never make the surfaces completely shiny and clean. Is it bad to have even invisible residues from the paste left on the surfaces before applying fresh paste?

If you're using isopropyl alcohol to clean the surface, then it will remove any substances that might affect thermal transfer in any significant amount. If you were just wiping the stuff off, then it's possible that you left some residue that could have some negative implications. If you don't have any alcohol, I suggest you simply head down to your nearest drug store and buy a bottle for a buck or so.

 

[Nenu]

...I'm told OCZ freeze is supposed to be non conducting and non capacitive, but I don't know how that would apply here...

If it is non conducting + non capacitive, there is no harm getting the paste on anything unless what you get it on needs air flow around it.
In your case, theres no harm.
As pointed out though, you want as thin a layer of thermal paste as necessary otherwise it will insulate a bit.

 

[Tzunami]

Coffee filters are also great for cleaning heat spreaders/heatsink surfaces as they are lint free. Qtips are fine, but cheep ones will leave lint.

 

[courtney01]

Ok thanks everyone.

 

[CraftyChicken]

I just wanted to add something. While TIM is usually non-conductive, at least the kind we use, if exposed to the air particulates will collect on it's surface. While unlikely, it is possible that it could cause could cause a short. That said, unless you've got gobs of stuff covering everything, I wouldn't worry to much.

If you are worried, here is how I clean up my messes. I use an old plastic library card, cut into two pieces cross-wise, to make a triangular scraper. I then just run the long edge, pointed side down, along the top of the socket/side of the CPU to scrape everything there. Wipe it off, and run it along the heatsink to clean up the last bit.