Thermal Paste... Ew.

[SkippyThorson]

I've got a question. This morning, I've been schmoozing around MacRumors, catching up on things, and came across a thread (probably not too far down the PPC page) where a user mentioned the shock of opening up his iMac G4 to dust and general filth.

I've always wanted to open it up and clean it out, and maybe even upgrade the Ram, but one thing has stopped me.

THERMAL PASTE.

Never, in my hardware-filled life, have I had to deal with Thermal Paste. The name alone sounds strange. Like denture cream, or Shoe Goo.

My question, and a question I'm sure many would like answered; how does this stuff work? I just slap it on the plate, press, and that's that?

Can you put on too little or too much? A dot the size of a pea? A quarter? I've heard so many horror stories about the ramifications of not reapplying it, that I've been scared into never opening my G4s. I don't even know where to get it, or where to get a good deal on it.

 

[skinniezinho]

http://www.youtube.com/watch?v=o7rPqCvCt0g

Guess this will help you

 

[maflynn]

Can you put on too little or too much? A dot the size of a pea? A quarter? I've heard so many horror stories about the ramifications of not reapplying it, that I've been scared into never opening my G4s. I don't even know where to get it, or where to get a good deal on it.

Thermal paste is used to mate to imperfect surfaces together to maintain/increase thermal transfer.

Since the CPU and its heatsink have tiny microscopic imperfections, the themal paste fills those in and allows an efficient transfer from the hot CPU to the heat sink.

If you put too much on, it actually makes matters worse by insulating, i.e., holding heat in. I usually use a razor blade to apply a thin coat on the cpu and then add the cpu cooler.

There's many ways to apply thermal paste, some do it by putting a dot on the middle the size of a pea, others use stripes, I prefer manually doing it ensure that I have full coverage before the cooler goes on.

 

[SkippyThorson]

Thermal paste is used to mate to imperfect surfaces together to maintain/increase thermal transfer.

Since the CPU and its heatsink have tiny microscopic imperfections, the themal paste fills those in and allows an efficient transfer from the hot CPU to the heat sink.

If you put too much on, it actually makes matters worse by insulating, i.e., holding heat in. I usually use a razor blade to apply a thin coat on the cpu and then add the cpu cooler.

There's many ways to apply thermal paste, some do it by putting a dot on the middle the size of a pea, others use stripes, I prefer manually doing it ensure that I have full coverage before the cooler goes on.

Your description is the first thing I've read that gave me a little hope that merely touching my computer won't result in its death.

My fear is that I'll break some super important seal, which I'll never properly repair, and I'll cause it to die within the same week.

Regarding these 2 metal plates that touch - does the thermal paste act to fill a gap between them, like 1/10 of an inch or something, or is it that they actually do make fairly strong contact with one another, and it's just meant to seal the bond? My other fear is that I'll take it apart, and they won't ever make contact again.

 

[fhall1]

Regarding these 2 metal plates that touch - does the thermal paste act to fill a gap between them, like 1/10 of an inch or something, or is it that they actually do make fairly strong contact with one another, and it's just meant to seal the bond? My other fear is that I'll take it apart, and they won't ever make contact again.

as maflynn said above: "Since the CPU and its heatsink have tiny microscopic imperfections, the themal paste fills those in and allows an efficient transfer from the hot CPU to the heat sink."

I bought my iMac G4 last October (in Utica as a matter or fact) and using the videos and teardown photos you can find on the web (and a couple dabs of Arctic Silver and an hour) I was able to open up the machine, clean out all the dust, bump up to 1GB RAM and install a bigger, faster hard drive. Cleaned off the old thermal paste, applied some new paste and buttoned it up. I build and repair PCs so it wasn't all that scary, just need to take your time (and have the right Torx driver).

Now it's running Leopard and has a new lease on life.

 

[SkippyThorson]

as maflynn said above: "Since the CPU and its heatsink have tiny microscopic imperfections, the themal paste fills those in and allows an efficient transfer from the hot CPU to the heat sink."

I bought my iMac G4 last October (in Utica as a matter or fact) and using the videos and teardown photos you can find on the web (and a couple dabs of Arctic Silver and an hour) I was able to open up the machine, clean out all the dust, bump up to 1GB RAM and install a bigger, faster hard drive. Cleaned off the old thermal paste, applied some new paste and buttoned it up. I build and repair PCs so it wasn't all that scary, just need to take your time (and have the right Torx driver).

Now it's running Leopard and has a new lease on life.

Small world!

I guess it doesn't sound as threatening as it used to. I feel a little better knowing what I know now. The iMac G4 is hands down my favorite computer of all time. (Which is why I bought both variations. (The iMac name on the front is a different font, among other internal changes, USB 2.0, etc.))

It also happens to be the only desktop computer I've ever had that I've never opened up. I've taken a vacuum to the top little vent holes above the fan, but I can't imagine what ~8-10 years of dust looks like in there.

Finally, my last question is, what brand or type of thermal paste is recommended? Is one better then another? You mentioned Arctic Silver. Is it one of those you-can-only-find-it-online things?

 

[fhall1]

If you do enough online research, Arctic Silver is probably the most recommended paste used by builders/modders.

Once in a while you'll get a deal online for it from Meritline or Cyberguys where you get a tube for a couple bucks with free shipping. If you have to pay shipping, it's usually more than the cost of the product.

Local to the U/R area, I've seen thermal paste at Best Buy and Staples (can't remember if it was Arctic Silver or not) if you have to "have it now". Once you open up and disassemble the iMac, don't put it back together and operate it without the paste in place. Clean the old paste off both surfaces with a paper towel and isopropyl alcohol, then put on the new.

Have fun....

 

[MacHamster68]

i always encourage people to try things themself , but if you never ever have done something like that my best advise is ask around friend's or family members who have some experience in taking computers apart , to look over your shoulder , other then that its not really something you need to be scared about , the youtube instructions are good when it comes to Mac's , just take your time , dont rush things and follow them step by step

http://www.youtube.com/watch?v=S72X9Gjy5WM

 

[SkippyThorson]

I'll keep all this newfound knowledge in mind. Thank you! Much appreciated, really.

I've asked around, and not one person I know has ever opened a G4. So, not only do my few tech savvy relatives / friends not know what the guts were like, they never knew it even needed 'thermal paste stuff'.

The YouTube videos posted in this thread both have and will certainly be helpful when I take the project on. I'll probably clean out both at once in the coming Summer when I'm otherwise bored - when not at one of my two jobs.

 

[Dave H]

Arctic MX-4 is made by the same company as Arctic Silver, but does not conduct electricity (no risk of shorted pins). I have used MX-2 and MX-3 (older versions that are also electrically non-conductive) and they have worked well.

 

[Makosuke]

Arctic MX-4 is made by the same company as Arctic Silver, but does not conduct electricity (no risk of shorted pins).

Just to note, for the OP, this nonconductive stuff is expected to be used on CPU heatsinks. The heat pipe on the G4 iMacs isn't anywhere near any circuitry; you'd need to put way, WAY too much on before you'd be at any risk of shorting something. Not that MX-4 wouldn't work, there's just no benefit of going out of your way or spending more to get it over Arctic Silver.

And just to add my pennies, the iMac isn't really pushing things as far as cooling goes compared to modern CPUs and GPUs, and the factory stuff on the heat pipe isn't all that great, so really, ANY thermal paste will work fine. I've used the big bottle of crappy stuff we have laying around the electronics lab at work on one, without issue. I only say this in case you find an off brand at a local store, so you don't worry that it won't get the job done.

 

[trickyred]

I'd never opened my iMac G4 until a few weeks ago, having had it for 7 nearly 8 years .... I've bought 3 off ebay and opened them all up since then!! I even installed a new optical drive in one (there wasn't one in there when I got it, which made it tricky as there was nothing to follow) and I didn't disconnect the bottom half either!!

Go for it!!

One thing I would add that I didn't see above although I may have missed it, don't get any paste in the hole on the mating surfaces,


Good luck!!

 

[fhall1]

...don't get any paste in the hole on the mating surfaces,


Good luck!!

That's what she said............sorry......couldn't resist.

 

[trickyred]

Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148a Safari/6533.18.5)

Omg how did I not realize that when I typed it??

 

[VanneDC]

ive taken em apart, stuck em back together /with/ and /without/ Thermal paste.. makes hardly any diff. even istat doesnt differ.. much...

great design the Imac G4.. love mine

if you have some, use the TP

 

[JoeG4]

Silver thermal paste is great if you're overclocking a high-end machine and need an extra degree or two of cool (if that). For an old iMac G4 (where the processor barely puts out 20w of heat, if that), there's no point in it.

It is true that you can probably put the machine back together without re-applying paste and it'll still work. I wouldn't, because the dust will probably get on it as you're cleaning it up and it's old and dried out anyway.

You should probably look into a new HD while you've got the machine apart though, for some reason Apple has this sixth sense about picking out the noisiest drives on Earth for iMacs.

The other thing about the white paste, is it's generally not electrically conductive like silver or copper is.. so you don't have to be super anal about it gooing off the edge and onto the board.

 

[DewGuy1999]

After looking at the Apple Service Source for the G4 iMac, it wasn't the thermal paste that bothered me but the admonishment for tightening the 4 torx screws with a torque driver:

Warning:
The bottom housing has four torx screws that must be tightened to at least 17 in.-lbs. Use a torque driver (service tool 076-0899) to ensure that the thermal pipe is firmly mated with the top base. If you do not have a torque driver, you must make sure the screws are tightened by hand FIRMLY, BUT NOT FORCIBLY.

Failure to apply the thermal paste as described in this procedure, and failure to tighten the torx screws as directed, could cause the computer to overheat and damage internal components.​

 

[JoeG4]

lmao torque screwdriver! I doubt you'd be able to apply all that much pressure to a torx bit anyway, not unless you have a REALLY good one.

 

[SkippyThorson]

Go for it!!

One thing I would add that I didn't see above although I may have missed it, don't get any paste in the hole on the mating surfaces,

Good luck!!

Well... That got really ugly really fast.

It is true that you can probably put the machine back together without re-applying paste and it'll still work. I wouldn't, because the dust will probably get on it as you're cleaning it up and it's old and dried out anyway.

On the note about being old and dried out, and not tying it in to the joke above... ...Should this be some sort of scheduled maintenance? Does the thermal paste lose some of its effectiveness over time? Perhaps re-application is good after some extended period.

Just trying to learn as much about this foreign substance as I possibly can.

After looking at the Apple Service Source for the G4 iMac, it wasn't the thermal paste that bothered me but the admonishment for tightening the 4 torx screws with a torque driver:

Warning:
The bottom housing has four torx screws that must be tightened to at least 17 in.-lbs. Use a torque driver (service tool 076-0899) to ensure that the thermal pipe is firmly mated with the top base. If you do not have a torque driver, you must make sure the screws are tightened by hand FIRMLY, BUT NOT FORCIBLY.

Failure to apply the thermal paste as described in this procedure, and failure to tighten the torx screws as directed, could cause the computer to overheat and damage internal components.​

That's possibly the most ridiculously small window of error I've ever seen. "The paste must be perfectly applied, and the screws must be tightened no more and no less than this amount."

Re-reading that last line, it almost sounds like instructions from the game Portal.

 

[JoeG4]

On the note about being old and dried out, and not tying it in to the joke above... ...Should this be some sort of scheduled maintenance? Does the thermal paste lose some of its effectiveness over time? Perhaps re-application is good after some extended period.

Yea, thermal paste can dry out, I recall hearing a figure around 8 years - I doubt it's something that's ever really been tested for 2 reasons:

1. Most computers aren't kept in use more than 10 years anyway
2. The kinda nerd that knows about thermal paste and all.. probably reapplies it when they pull their computer apart anyway.

I've never had a computer's thermal transfer setup randomly fail so.. I doubt it really happens. Only up until around 2003 did Apple even start using thermal paste anyway (I think before that, they just used stick-on pads)

Truth be told, I wish they had stuck with that. XD

 

[fhall1]

Don't worry about the torque driver....I put mine back together without one....no problems 5 months later.

 

[OrangeSVTguy]

Don't worry about the torque driver....I put mine back together without one....no problems 5 months later.

LOL. I've taken them apart before too and that's the first time I've ever heard the word of a torque screw driver and iMac in the same sentence let alone same paragraph. Probably just one of Apple's "scare tactics" to keep you out of their hardware

Just hand tighten without stripping the torx head and you'll be good to go.

BTW: You can get Artic Silver at Radio Shack, they also sell a cheaper silicone based stuff too that works just as fine.

 

[DewGuy1999]

LOL. I've taken them apart before too and that's the first time I've ever heard the word of a torque screw driver and iMac in the same sentence let alone same paragraph. Probably just one of Apple's "scare tactics" to keep you out of their hardware

Just hand tighten without stripping the torx head and you'll be good to go.

BTW: You can get Artic Silver at Radio Shack, they also sell a cheaper silicone based stuff too that works just as fine.

Since the iMac Service Source isn't normally available to the public I imagine it's there to have their AASPs perform the work "correctly". A few years ago, I had considered opening my iMac up to upgrade the top RAM and got a hold of the Service Source, but it scared me off with the torque driver business so I never did anything. Now, I think a new Mac will be a better investment than spending money upgrading something this old for what would amount to a small gain.

 

[sbabolat]

Hi,
Long time reader, first time poster!

I know this thread is a couple month old, but I have a related question (and need your input).
I got those past few days a couple of imac g4 and emacs for my classroom.

I cleaned them up (vacuum and air spray the outside, remove some visible/accessible dust from the outside).
As a previous poster stated, I tinker with computer, but never used thermal paste.

The imac g4 has 512Mb (upgraded from 256 as stated on the bottom housing). It was full of dust (removed) but now I am wondering if the previous owner has applied the paste.

I am "scared" of doing it as i never did it. Do I have to?
Is it really worth it (given the age/price they are...)?

Thanks

S.

 

[Intell]

G4 iMacs come with thermal paste from Apple already installed. If the iMac has never been opened, apart from removal of the bottom metal plate, then the thermal plate is still intact and proper. If the iMac has been opened, best hope that the person that opened it reapplied it, or the iMac could overheat or the two parts could be permanently fused together. It is a must to have thermal paste on modern computers. There are a few rare cases where it isn't needed, but it is very much needed on G4 iMacs.