[Amps] Arctic Silver

[Roger (K8RI)]

It's not rocket science although there is a bit of a learning curve.
Done properly, there is no excuse for air bubbles.
Put a pile of heat sink compound in the center of the metallic cover on 
the CPU.  Apply the heat sink straight down onto the compound with a bit 
of a back and fourth twisting motion. You may have to do this several 
times to get the proper amount. When done correctly the two surfaces 
will hold on to each other with out excess flowing over the side.
Be willing to sacrifice some compound if you've not done this before.
Note, too thick a layer will greatly reduce the compounds ability to 
transfer heat!

Cost?  The best only costs a few cents more per application than the 
cheap stuff and is substantially cheaper than the old Silicone thermal 
grease of the early days. I had a 10 oz tube of that stuff (I worked for 
a company that made it) that cost me a buck.  I still have most of it, 
but the tube is getting pretty beat up.  I haven't used any of that 
since we quit using those little "screaming" 90 mm fans.  They were 
worse than the air noise from a 10 KW amp.

BTW, I actually did find "Silicone grease" offered.  It was an 
unbelievable $4.99 for a 1 gram pack. 11 or more dropped it to $4.45.  A 
2.7g applicator of  Arctic Silver Ceramique sells for $4.99  A 20 gram 
applicator is $8.99.  The same amount silicone grease would be $89.  Get 
any of these in bulk and you have handling and application issues.

Price depends highly on packaging. Having worked in the industry, as a 
SWAG I's say the packaging cost several time the cost of the silicone 
grease inside.

Go to www.newegg.com and search on "Heat transfer compounds". It's by no 
means the comprehensive list of what they carry, but give an idea as to 
what's available and costs.  You can find a lot more with detailed searches.

Viscosity?  Forget it and don't worry about it unless you make your ow, 
or purchase large lots.  Virtually ALL commercial compounds are of the 
correct viscosity that let you get a "uniform" layer measured in 
microns, "without air bubbles.  The mor common compounds do cover a 
variety of viscosity as do OEM bulk shipments, meaning the average user 
has a lot more knowledge of metal to metal and metal to ceramic 
interfaces that the typical ham or computer enthusiast.
How many know the difference between 10 Cs and 6000 Cs?.  10Cs is for 
dry fly treatment while 6000 is like Taffy.  What's 6000 used for.  I 
saw it in the labs but I retired in 97 and have no recollection as to 
its use.

Why use the good stuff for less demanding applications when there is 
little, if any difference in cost?  I'd say, ease of installation with 
the knowledge you used good stuff.  When using the "good stuff" you 
simply put "enough" on the surfaces and stick the together, knowing they 
will work.  Less efficient compounds may require more care when used.
The less efficient is likely to become difficult to find as the primary 
use dries up.  However, when it comes to price, it is to their advantage 
to use the "cheapest" that "should" do the job, often relying on 
manufacturers claims as to the product's characteristics.

Industry generally abandons a product before it reaches the point of 
negative return.

BTW, if you lap a pair of steel (or any other metal surfaces) optically 
flat and put them together (dry), they will be extremely difficult to 
get apart.  They stick so well that you may not be able to align the 
edges.  Left in this state, some metals will weld themselves together.  
These compounds allow for small irregularities to exist in that metal to 
metal interface and still transfer in areas that would have not been in 
intimate contact.

Getting heat sink and CPU surfaces optically flat is labor intensive and 
impractical.  Keeping them in that state through time, handling, and 
temperature changes would require special handling as well as training 
of anyone who handled them, making the cost much higher than today's 
mass produced CPUs, GPUs, and cooling devices.

73

Roger (K8RI)


On 4/11/2015 1:54 PM, Mike Waters wrote:
> This is generally good advice. However, as Manfred nicely pointed out,
> "...applying an ultra thin, even layer is almost a guarantee for entrapping
> air bubbles. And that's definitely worse than a thick grease layer!".
>
> I fully agree with Manfred. It depends on the viscosity of the grease,
> whether it's thin enough to be easily squeezed out by applying pressure.
>
> 73, Mike
> www.w0btu.com
>
> On Sat, Apr 11, 2015 at 9:21 AM, Kevin Stover <kevin.stover at mediacombb.net>
> wrote:
>
>> If after securing the transistor to the heat sink or heat sink to a
>> processor you see heatsink compound oozing out the sides you've used waaay
>> to much.
>>
>> The layer of heatsink compound needs to be an even layer almost thin
>> enough to see through, with NO air bubbles.
>>
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