CPU thermal paste?

~misfit~ wrote:
WebWalker wrote:

On Mon, 26 Apr 2004 19:02:37 -0700, Ablang
wrote:


I just inherited a K6-2 300 Mhz computer, but the CPU fan & heatsink
keeps falling down off the CPU, which means that the thermal paste
is no longer sticking.

Thermal paste don't really sticky like glue and it is more like
toothpaste.


What you now know as thermal paste has only been around for a few years. The
early stuff was "sticky like glue", in fact it doubled as glue as a lot of
the HS's with this stuff didn't have clips.


Not for K6-2 300 era chips. For chips prior to the P100 yeah, it's not
uncommon.

--
~misfit~




--
spammage trappage: replace fishies_ with yahoo

Ablang wrote in message . ..

I just inherited a K6-2 300 Mhz computer, but the CPU fan &
heatsink keeps falling down off the CPU, which means that
the thermal paste is no longer sticking.

Does anyone know a good place online where I can buy this
cheap, or perhaps someone has ideas for other ways of keeping
the fan & heatsink in place (vertically)?

A 300 MHz K6-2 is not the world's hottest chip and doesn't need any
special thermal adhesive, but ignore hacks who tell you to apply
thermal grease in the enter and a drop of super glue in each corner or
mix thermal grease with epoxy, both bad remedies.

Thoroughly clean off the heatsink and the metal part of the chip
package with alcohol, then glue them back together with ordinary
silicone rubber sealant (RTV). Apply a thin layer of RTV all over the
mating surface, just as you would apply thermal grease, by pressing
the heatsink firmly and sliding it around slightly to spread the RTV
and squeeze out the excess. Keep the chip horizontal for an hour, and
handle it gently for the next 8 hours.

Regular epoxy can be used instead and applied the same way, but the
drawbacks to any epoxy are that it runs and drips and the heatsink
will be much harder to remove later on, while RTV remains so soft that
it can be easily cut with a knife yet sticks very well.

do_not_spam_me wrote:
Ablang wrote in message . ..


I just inherited a K6-2 300 Mhz computer, but the CPU fan &
heatsink keeps falling down off the CPU, which means that
the thermal paste is no longer sticking.

Does anyone know a good place online where I can buy this
cheap, or perhaps someone has ideas for other ways of keeping
the fan & heatsink in place (vertically)?


A 300 MHz K6-2 is not the world's hottest chip and doesn't need any
special thermal adhesive, but ignore hacks who tell you to apply
thermal grease in the enter and a drop of super glue in each corner or
mix thermal grease with epoxy, both bad remedies.

They make specialised thermal epoxy for attaching heat sinks to RAM
(both system and video) chips. I'd use that, if getting a proper heat
sink with a retainer clip was out.


Thoroughly clean off the heatsink and the metal part of the chip
package with alcohol, then glue them back together with ordinary
silicone rubber sealant (RTV). Apply a thin layer of RTV all over the
mating surface, just as you would apply thermal grease, by pressing
the heatsink firmly and sliding it around slightly to spread the RTV
and squeeze out the excess. Keep the chip horizontal for an hour, and
handle it gently for the next 8 hours.

Regular epoxy can be used instead and applied the same way, but the
drawbacks to any epoxy are that it runs and drips and the heatsink
will be much harder to remove later on, while RTV remains so soft that
it can be easily cut with a knife yet sticks very well.

I can't wait to get some old-ish equipment to play around with this
idea! :-)


--
spammage trappage: replace fishies_ with yahoo

On Tue, 27 Apr 2004 15:03:39 +0800, beav AT wn DoT com DoT au wrote:

Wes Newell wrote:
The thermal paste isn't supposed to stick. That's not what it's for. There
should be a clip on the cpu cooler that attaches to thenubs on 2 sides of
the socket to hold the HS in place. If your cooler doesn't have this, then
you've got the wrong cooler.

Not all cpu heatsinks were clipped on. The socket /should/ have clips
on it, but older cpus (notably the DX2-66 overdrive) just have small
heatsinks stuck on with thermal adhesive (horrible stuff). Given that
there are clips on the socket, there should be no problem attaching a
new HSF.

But he doesn't have a a 486 cpu. he's got a K6-2-300 Pentium class and it
fits in a socket7. The proper cooler will have a spring clip that
attaches to the nubs of the socket.

--
Abit KT7-Raid (KT133) Tbred B core CPU @2400MHz (24x100FSB)
http://mysite.verizon.net/res0exft/cpu.htm

Wes Newell wrote:

But he doesn't have a a 486 cpu. he's got a K6-2-300 Pentium class and it
fits in a socket7. The proper cooler will have a spring clip that
attaches to the nubs of the socket.


The 486 is the most notable, as it was the first to commonly be fitted
with active coolers, so having an overdrive chip with a passive cooler
was strange...

--
-Luke-
If cars had advanced at the same rate as Micr0$oft technology, they'd be
flying by now.
But who wants a car that crashes 8 times a day?
Registered Linux User #345134

sooky grumper wrote:

~misfit~ wrote:
WebWalker wrote:

On Mon, 26 Apr 2004 19:02:37 -0700, Ablang
wrote:


I just inherited a K6-2 300 Mhz computer, but the CPU fan & heatsink
keeps falling down off the CPU, which means that the thermal paste
is no longer sticking.

Thermal paste don't really sticky like glue and it is more like
toothpaste.


What you now know as thermal paste has only been around for a few years.
The early stuff was "sticky like glue", in fact it doubled as glue as a
lot of the HS's with this stuff didn't have clips.


Not for K6-2 300 era chips. For chips prior to the P100 yeah, it's not
uncommon.



Yea my P100 has a "factory installed" HSF that is glued o the chip.

BTW thermal grease has been in use in the electronic industry for decades. I
recall the early automotive electronic ignitions used the same while paste
to mount their modues and that was 30 years ago.
--

Stacey

sooky grumper wrote in message ...
do_not_spam_me wrote:
Ablang wrote in message . ..

I just inherited a K6-2 300 Mhz computer, but the CPU fan &
heatsink keeps falling down off the CPU,

ignore hacks who tell you to apply thermal grease in the enter
and a drop of super glue in each corner or mx thermal grease
with epoxy, both bad remedies.

Thoroughly clean off the heatsink and the metal part of the
chip package with alcohol, then glue them back together with
ordinary silicone rubber sealant (RTV).

Regular epoxy can be used instead and applied the same way,
but the drawbacks to any epoxy are that it runs and drips
and the heatsink will be much harder to remove later on

They make specialised thermal epoxy for attaching heat sinks
to RAM (both system and video) chips. I'd use that, if getting
a proper heat sink with a retainer clip was out.

I have 2 old jars of Delta Bond thermal epoxy but haven't used them,
except when I needed a putty-like epoxy, and to glue on heatsinks I've
used only silicone rubber RTV, except in the case of large heatsink
and a small contact area, where I used regular epoxy. Thermal epoxy
for a 300 MHz K6-2 is an utter waste of money.

On Tue, 27 Apr 2004 22:21:10 +1200, "~misfit~"
wrote:

WebWalker wrote:
On Mon, 26 Apr 2004 19:02:37 -0700, Ablang
wrote:

I just inherited a K6-2 300 Mhz computer, but the CPU fan & heatsink
keeps falling down off the CPU, which means that the thermal paste
is no longer sticking.

Thermal paste don't really sticky like glue and it is more like
toothpaste.

What you now know as thermal paste has only been around for a few years. The
early stuff was "sticky like glue", in fact it doubled as glue as a lot of
the HS's with this stuff didn't have clips.

Thermal "paste" has been around for ages. First used it the 60's for some
early transistor power amps. Has been used for years in the
electronics/computer industry. It was "discovered" for CPUs when the heat
started rising, and heatsinks started being needed.

JT

JT wrote:
On Tue, 27 Apr 2004 22:21:10 +1200, "~misfit~"
wrote:

WebWalker wrote:
On Mon, 26 Apr 2004 19:02:37 -0700, Ablang
wrote:

I just inherited a K6-2 300 Mhz computer, but the CPU fan &
heatsink keeps falling down off the CPU, which means that the
thermal paste is no longer sticking.

Thermal paste don't really sticky like glue and it is more like
toothpaste.

What you now know as thermal paste has only been around for a few
years. The early stuff was "sticky like glue", in fact it doubled as
glue as a lot of the HS's with this stuff didn't have clips.

Thermal "paste" has been around for ages. First used it the 60's for
some early transistor power amps. Has been used for years in the
electronics/computer industry. It was "discovered" for CPUs when the
heat started rising, and heatsinks started being needed.

Yep, I know that. I was talking specifically about the PC side of things. I
have a mate who's into electronics and I remember him using "thermal
transfer compound" on some of the transistors/heatsinks on his home-made
power amplifiers 20+ years ago. I don't kmow what it was made of but I do
remember him telling me it was really toxic. Zinc oxide? That seems to ring
a (faint) bell.
--
~misfit~

"do_not_spam_me" said in
om:

I have 2 old jars of Delta Bond thermal epoxy but haven't used them,
except when I needed a putty-like epoxy, and to glue on heatsinks I've
used only silicone rubber RTV, except in the case of large heatsink
and a small contact area, where I used regular epoxy. Thermal epoxy
for a 300 MHz K6-2 is an utter waste of money.

Silicone rubber to affix a heatsink? Geez, why not just thermally
isolate the heatsink with a thick rubber washer and some contact cement?
Why even bother affixing the heatsink at all? It would be better to not
use anything and just press the heatsink and CPU together dry to get as
much metal to metal contact as possible. There are some silicone-only
based thermal pastes for something like 15 cents a blister tube which
are about the same as using double-stick thermal tape (a 1" x 6" strip
good for 2 or 3 uses costs $2). Even the alumina-based thermal pastes
are much better than silicone only (especially compared to what you
mentioned). A single-purchased blister costs all of 65 cents. Skip the
small fries with your next burger meal if you're that hard up for pocket
change. If you really need to use a thermal adhesive and you don't want
to pay the high bucks for the Artic brand (which seems to be the most
popular brand offered almost to exclusivity), make your own
(http://www.overclockers.com/tips683/).

There's a reason no one includes silicon *rubber* in their testing of
thermal compounds in test reports, like
http://www.techwarelabs.com/reviews/...thermal_paste/ and
http://www.thetechzone.com/reviews/r...nd/index.shtml.
Silicone rubber is a thermal *insulator*, not a conductor. Yeah, it
transfers heat 4 times faster than air but that still sucks! Might as
well as use Hard As Nails from a glue gun ("Hey, hold on Joe. While
you're gluing those 2x4's on the basement block, dab a bit of that Hard
As Nails on my heatsink, will ya?"). Thermal paste (and worse for
thermal adhesive) aren't great for thermal transfer but they beat air
and silicone by a long ways. Silicone *rubber* RTV (room temperature
vulcanizing; i.e., it sets at room temperature) to attach a heatsink? I
don't think so. That's the stuff you use as a moisture barrier or
sealant, like around your bathtub, or to insulate wire connections, like
gooping it into a wire nut for an outdoor wire splice. It is NOT to
provide thermal transfer between a CPU and heatsink, or thermal transfer
between any surfaces. You might as well as use double-stick foam tape
(the super dense type). Thermal tape would be better (and less messy)
but is still at the low end. Go read
http://www.azom.com/details.asp?Arti..._Vulcan ising.

Thermal transfer:
air ~ 0.035 W/mK
silicone rubber = 0.14 to 0.22 W/mK
3M thermal tape = 0.4 W/mK
silicone/zinc grease or paste = 0.4 to 0.9 W/mK
copper filled silicone grease = 2.0 W/mK
alumina (Artic or generic) = 4.0 W/mK
silver filled silicone grease = 4.2 W/mK
Artic Silver epoxy = 7.5 W/mk
Artic Silver 3 = 9.0 W/mK
Artic Silver 5 = 350,000 W/mK (claimed)

I don't see how Artic can claim their Silver 5 compound, a *paste*, has
a thermal transfer rate that is 814 times greater than solid silver
itself. When I Googled around, no one actually tested this claim and
instead just quotes Artic's own specs. By the way, little known fact
(well, it was to me until now): there was no Artic Silver 4 because "4"
in Japanese is "shi" which means "death" (see
http://www.techaddicts.net/ArcticSilver5/AS5_1.html). Guess they didn't
want a thermal compound with a connotation of "Artic Silver Death".
Yeah, put this on, then your CPU dies. ;-

The biggest problem I see with users applying thermal paste is they goop
on way too much of it. Metal-paste-metal doesn't transfer heat as fast
as metal-metal contact. The paste is only supposed to fill any
microscopic or concavity voids that would otherwise be filled with air.
Of course, if you would rather rely on the most metal-to-metal contact
to provide the greatest rate of thermal transfer, welcome to the world
of lapping your heatsink (and CPU plate which is hazardous).

Gold?

Hmm, just had a thought but no time to think it through. Silicone,
zinc, aluminum, and silver, in that order, give increasiningly better
heat transfer rates. Wouldn't gold be even better? But imagine the
price for gold-filled compounds!

Oops, never mind. Did some searching to find the thermal conductance of
some metals, which are (along with some other materials):

Diamond = 1000 to 2600 W/mK (wow!)
Silver = 430 W/mK
Copper = 390 W/mK
Gold = 320 W/mK
Aluminum = 236 W/mK
Platinum = 70 W/mK
Glass = 1 W/mK
Air = 0.035 W/mK
Styrofoam = 0.03 W/mK

The above are for solid materials, not for pastes filled with micronized
filler using the above materials. Just imagine the cost for
diamond-filled thermal paste! Ouch.

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