pads or grease??? for testing

[superart]

I did a search for this topic, but was surprised to find that not much has been discussed about it.

I am wondering, what would be better for testing? Thermal paste such as AS or a thermal pad?

I realize that thermal paste is much better in regards to performance, but in the test bench environment, consistency is more important than performance.

The way I see it, thermal pads provide much more consistency than grease. Not only is it hard to constantly apply a constant coating of grease each and every trial, but the grease itself is not uniform. From what I understand, AS and other metal based greases are heterogeneous mixtures. So one drop of AS, even from the same tube, will not necessarily be the same as the next.


I look forward to any comments, suggestions, flames you guys could offer.

-- Thanks.

[bigben2k]

We did discuss it, but probably more within the scope of lapping.

Thermal pastes have a cure time, which can add a variable to the test. Arctic Silver actually makes a paste especially for testing, but you have to contact them for it.

Pads may have a special curing procedure, which would involve heating it, to make it settle.

What it comes down to, either way, is repeatability.

A paste can be applied with a certain level of repeatability, as pHaestus has learned to do so well, but there's still going to be a little variance.

Not sure that pads are that much more repeatable, even after curing.

This is something I'll be investigating, once my testbench is up and running. Progress on the wbta site (see sig).

[superart]

Originally Posted by bigben2k

A paste can be applied with a certain level of repeatability, as pHaestus has learned to do so well, but there's still going to be a little variance.

Not sure that pads are that much more repeatable, even after curing.

What makes me think that pads could offer more repeatability is that they are produced by machines and come in one constant thickness. whareas spreading out paste is subject to human factors and error.

[pHaestus]

They are such a pita to clean though!

I'd look to things like Ir foils before going the thermal pad route. I have a method now for wb testing that I am pretty satisfied with (though there's some trial and error). I have it about halfway written up.

As an aside, have you guys tried tightening down wbs, loosening wingnuts a good bit, retightening past AMD recommended pressure, and then loosening back to recommended force? This seems to give me the best temperatures (I think I am forcing all the excess paste out in a little more repeatable manner regardless of initial application thickness)

[jaydee]

Originally Posted by pHaestus

They are such a pita to clean though!

I'd look to things like Ir foils before going the thermal pad route. I have a method now for wb testing that I am pretty satisfied with (though there's some trial and error). I have it about halfway written up.

As an aside, have you guys tried tightening down wbs, loosening wingnuts a good bit, retightening past AMD recommended pressure, and then loosening back to recommended force? This seems to give me the best temperatures (I think I am forcing all the excess paste out in a little more repeatable manner regardless of initial application thickness)

How are you measuring the pressure on the mounting hardware?

[pHaestus]

HIGHLY scientific (sarcasm filters engaged)

I use wingnuts and adjust them to all be vertical

[jaydee]

Originally Posted by pHaestus

HIGHLY scientific (sarcasm filters engaged)

I use wingnuts and adjust them to all be vertical

LOL, I was expecting to hear "small tourque wrench".

[superart]

Originally Posted by jaydee116

LOL, I was expecting to hear "small tourque wrench".

Ye remember we were talking about that the other day, Ph.

I like this one:
http://www.sears.com/sr/javasr/produ...=specs#tablink