Thermal grease vs Vaseline?

[Jethro]

IIs Vaseline an acceptible substitute for thermal grease for a CPU?
A friend wants to know.

Thanks

Jethro

 

[Gerard Bok]

IIs Vaseline an acceptible substitute for thermal grease for a CPU?

No!

Vaseline (or petroleum gell as it is known in the US only
makes it easier to remove the cooler from your CPU if you need to
toss it away after overheating

 

[CBFalconer]

No!

Vaseline (or petroleum gell as it is known in the US only
makes it easier to remove the cooler from your CPU if you need to
toss it away after overheating

It also has other uses. Off topic here.

 

[Paul]

IIs Vaseline an acceptible substitute for thermal grease for a CPU?
A friend wants to know.

Thanks

Jethro

The thermal paste is a carrier for a solid. The "grease" itself is not
the thing to concentrate on.

For example, here is the MSDS for Arctic Silver Ceramique. The solid
particles trapped in the paste are:

http://www.arcticsilver.com/PDF/ceramique_msds.pdf

Aluminum Oxide
Boron Nitride
Zinc Oxide

The Zinc Oxide is what you'd find in Radio Shack paste. They have
tiny tubes of that stuff, and the carrier is kinda runny and won't
stay in place. That is not my favorite compound and I would not
use the Radio Shack stuff.

Boron Nitride is, as far as I know, a mainstay of paste makers. It
is quite popular as an insulator, with thermally conducting properties.

I'm not familiar with the Aluminum Oxide, and what its properties
might be.

At least the Wikipedia article on Aluminum Oxide mentions it is
thermally conductive, making it in the same class as the others.

http://en.wikipedia.org/wiki/Aluminum_Oxide

The MSDS for Arctic Silver is here:

http://www.arcticsilver.com/PDF/as5msds.pdf

It has all the same materials as Ceramique, but includes metallic
Silver as well. The claim here is it is slightly capacitive
when smeared on any components around the top of the processor,
such as the resistors and caps on the top of a Barton S462. In
general, you don't want to get thermal compounds on places other
than the heat spreader or the top of the die.

http://www.arcticsilver.com/as5.htm

They even make a cleaner.

http://www.arcticsilver.com/arcticlean.htm

Vaseline would function as a carrier, but once it became molten
and runny, would flow away, leaving nothing behind (just the usual
air gap, causing the processor to overheat). You'd have
to mix the above listed solids with it, to give it desirable
properties. The carrier has to be selected, such that it won't
pump out, due to thermal expansion and contraction that occurs
when the processor heats and cools. Naturally, the above solids
are pretty finely ground.

Paul

 

[kony]

IIs Vaseline an acceptible substitute for thermal grease for a CPU?
A friend wants to know.

Thanks

Jethro

No, the ideal grease will not change from a solid to an ever
thinner liquid then burn up. If you're playing around with
alternative household products then the closest thing would
probably be a synthetic bearing grease with copper in it.
There is no need for substitutes though, just use the proper
grease... it's made to do this job(!).

 

[DaveW]

In a word, no. However, the flaming CPU that would result from the use of
Vaseline might be just the kind of entertainment your friend needs...

 

[philo]

It also has other uses. Off topic here.

OT???

Well that reminds me of the newly-weds who mistook a jar of putty for a jar
of vaseline.


yep , you guess it...


all their windows fell out <G>

 

[Cessna 310]

IIs Vaseline an acceptible substitute for thermal grease for a CPU?
A friend wants to know.

Thanks

Jethro

Vaseline is not the right heat-conducting material. It is not designed
to conduct heat. So even if it does smooth under pressure, its film
will break down with heat and it won't pass the CPU heat efficiently to
the heat sink

The use of expensive heat conducting material is pretty much as waste of
money. Arctic Silver and such don't do much better than other material.
There are substitutes that are designed to conduct heat, will form a
thin film and not break down under heat.

I've been using common wheel-bearing grease for some time very
successfully. It requires spreading a thin layer of grease over the CPU
and then applying the heat sink. Little twists of the heat sink will
make sure the material is seated and a smooth thin layer will formed.
This material conducts heat efficiently and does not break down in the
heat of CPU operation. Its designed to conduct heat and maintain its
thick viscosity under the high heat and stress of the wheel bearing.
Its even possible to use the thin layer of grease on the CPU and then
apply a heat sink with the pad still on it.

The added bonus is that the heat sink is more easily removed than with a
typical heat pad on most heat sinks. I've done that more than a couple
of times.

I'm using this on several overclocked Athlon 64 X2s and single core Ath
64s. None of these machines get temps above 115F even operating at full
load. Idle near room temp w/ Cool 'n Quiet.

 

[kony]

Further to Gerard's reply, stay well clear of the common white paste you
see in TV's and amplifiers etc... totally useless for CPU, this stuff
tends to dry out rather quickly.

Use Artic Silver or similar paste as this tends not to dry out,

While you are correct, the problem with generic silicone
grease drying out was most prevalent on small open cores
like some video cards, Pentium 3 or Athlon socket A era. On
chips with heat spreaders it'll tend to last at least a
couple of years if not longer... but still you're right that
it will eventually be a problem, degraded performance, yet
there are people installing crap fans or PSU that die in an
couple years too so it has to be seen in perspective.

 

[Jethro]

Vaseline is not the right heat-conducting material. It is not designed
to conduct heat. So even if it does smooth under pressure, its film
will break down with heat and it won't pass the CPU heat efficiently to
the heat sink

The use of expensive heat conducting material is pretty much as waste of
money. Arctic Silver and such don't do much better than other material.
There are substitutes that are designed to conduct heat, will form a
thin film and not break down under heat.

I've been using common wheel-bearing grease for some time very
successfully. It requires spreading a thin layer of grease over the CPU
and then applying the heat sink. Little twists of the heat sink will
make sure the material is seated and a smooth thin layer will formed.
This material conducts heat efficiently and does not break down in the
heat of CPU operation. Its designed to conduct heat and maintain its
thick viscosity under the high heat and stress of the wheel bearing.
Its even possible to use the thin layer of grease on the CPU and then
apply a heat sink with the pad still on it.

The added bonus is that the heat sink is more easily removed than with a
typical heat pad on most heat sinks. I've done that more than a couple
of times.

I'm using this on several overclocked Athlon 64 X2s and single core Ath
64s. None of these machines get temps above 115F even operating at full
load. Idle near room temp w/ Cool 'n Quiet.

Thanks for the many responses. I have passed them all along to my
friend to do with as he will. Personally I have always used the stuff
sold especially for his, but maybe next time I might try wheel bearing
grease. I always have some of that around.

Jethro

 

[Gerard Bok]

Well that reminds me of the newly-weds who mistook a jar of putty for a jar
of vaseline.

As far as I know, PuTTY it the way to go if you want to establish
a reliable link

 

[Cessna 310]

Speaking from experience I have seen TV's and video's where the failure
of power transistors and FETs in the switchmode supply due to the
actual white stuff from drying out... infact one manufacturers
modification was to remove this white stuff and replace it with their
recommendations (usually their own stuff costing that little bit more)..
I literally had to scrub the old white stuff off from Tv's and video's
less than 12 months old. When things are under warrenty you have to
repair them to the manufacturers specs or they don't wanna know should
they have to have it back.

Common wheel bearing grease.. well thats new just remember there's
wheel grease and wheel grease but you don't say what brand it is...

"Coastal Industrial Moly EP Grease"

but grease also forms a film and why don't all manufacturers use it...
there's a heck a lot if it about, tonnes of it..?

Dunno. But I'm NOT the only one using it.

This heat sink stuff contains oxides which comes in all proportions as
to brand... you gotta admit that the white stuff is far more thicker
than the stuff you see on CPUs and takes more pressure to spread.

All we are interested in is filling the gaps the mating surface with a
heat conducting agent such as a metal oxide.

Davy

Having smooth mating surfaces and reasonable pressure on the CPU and
heatsink will help reduce the amount of "fill" necessary. Applying the
material correctly should result in such a thin layer. Its very
important to have a smooth material that will flow out, conduct the heat
through that very thin later, and not break down are the important
characteristics. These are the exact characteristics of the wheel
bearing grease noted above.

From what I've observed trying different heat conducting materials,
there really isn't that much performance difference between them.

But your machine is not my nickel, so you need to choose your own poison.

 

[kony]

Speaking from experience I have seen TV's and video's where the failure
of power transistors and FETs in the switchmode supply due to the
actual white stuff from drying out...

While it could "somewhat" be true, not directly so.
If the grease is merely average quality and the part being
'sunk isn't overdriven onto the point of ultimately drying
out the grease because it was excessively hot all along, it
will be sufficient for the life of the product and even 20
years longer. In other words, a spot of grease can't make
up for poor engineering or later penny-pinching in a design,
nor can a better grease than that "white stuff".

infact one manufacturers
modification was to remove this white stuff and replace it with their
recommendations (usually their own stuff costing that little bit more)..
I literally had to scrub the old white stuff off from Tv's and video's
less than 12 months old. When things are under warrenty you have to
repair them to the manufacturers specs or they don't wanna know should
they have to have it back.

It is not an indictment of "white stuff" in general,
certainly some of it is really poor, but that doesn't weight
against the average grade compound.

Common wheel bearing grease.. well thats new just remember there's
wheel grease and wheel grease but you don't say what brand it is...

Right, because it doesn't matter. Synthetic based wheel
bearing grease is essentially similar formula as the
infamous arctic silver, except the particles are not
abrasive and are moderately larger. It is beside the point
though, that there is no reason to use it unless one were
stranded on a deserted island with everything (computer,
power, etc,) but thermal grease - an unlikely scenario.
Once the thought of vaseline came up it was just a silly
daydream thought, not a serious use.

but grease also forms a film and why don't all manufacturers use it...
there's a heck a lot if it about, tonnes of it..?

You seem to suggest a "film" is some bad thing. It is the
goal. However, the surfaces are typically nonplaner enough
that the gaps in many areas are larger than one particle in
heatsink compound, which is essentially a thick oil or
grease, with the solids added to be more thermally
conductive than the "grease" carrier alone would be. Plus,
adding the solids reduces the pumping of the carrier by not
only making it more viscous, but by the greater thermal
conduction reducing the interface temp.

This heat sink stuff contains oxides which comes in all proportions as
to brand... you gotta admit that the white stuff is far more thicker
than the stuff you see on CPUs and takes more pressure to spread.

If you have gotten ahold of a product that is too viscous
for your particular use it is not at all indicative of all
"heat stink stuff". It's not as though there is only one
vat of the stuff from one manufacturer, just as there are
variations of many many different products, not all
so-called generic white thermal compound is a reasonable
quality. If you bought a poor quality car, do you swear off
all cars and buy a horse?

All we are interested in is filling the gaps the mating surface with a
heat conducting agent such as a metal oxide.

Yes, which any normal quality white grease will do fine.
There is a minor gain in some exotic compositions, and in
very high heat density situations there is a further gain in
going with a synthetic base oil/grease instead of silicone.
That situation is not present on today's CPUs because they
have heat spreaders. The thing to avoid is any very low
quality grease, or any very low quality factory applied
thermal interface material, or any very low quality
heatsink, motherboard, CPU, etc, etc.

 

[Vanguard]

IIs Vaseline an acceptible substitute for thermal grease for a CPU?
A friend wants to know.

An acceptible solution for what? For polishing his bishop?

You are not trying to insulate the heatsink from the processor. You are
filling microscopic air gaps. Best is metal-to-metal contact for heat
transfer. Worst is air-to-metal. In between is paste-to-metal but it
is nowhere as good as metal-to-metal. You want to apply a transparently
thin layer to fill the microscopic air gaps because you want the most
metal-to-metal contact.

So just when has your "friend" ever seen vasoline sold as CPU thermal
compound?