Real laboratory tests of thermal pastes on igor’sLAB – Part 1 – Measurement setup and methodology

1 - Introduction and basics 2 - Thermal conductivity and disruptive factors 3 - From thermal resistance to thermal conductivity 4 - How the TIMA5 works with ASTM D 5470-17

After almost 12 months of preliminary work and several foundational articles on the subject, the time has finally come: the world’s first editorially based testing station for thermal paste and thermal pad analyses according to ASTM D5470-17 is now complete and already in the trial phase. Whether it’s the thermal conductivity or thermal resistance of thermally conductive materials or a material analysis, from now on I can actually test (almost) everything and not just evaluate it subjectively. I have already teased you sporadically from time to time, but today the time has finally come and I can introduce you to my current major investment in the lab, because in the end the Keyence VHX 7000 from 2023 and now the TIMA5 from Nanotest are also part of a well-structured plan to restructure the content of my work, which will be joined in the foreseeable future by a completely redesigned fan measuring stand with professional sensors and extended infrared measurements through to thermal microscopy.

Disclosure of technology and methods is also part of transparent work and so I cannot and will not withhold the necessary theoretical basics from you today. But don’t worry, I will explain it as simply as possible. But it is absolutely necessary to write something about it, because the information currently circulating in the data sheets on the individual thermal conductive pastes is almost always not worth the paper on which the PDF was not printed. And it will certainly also create a small amount of work for the packaging industry if many boxes and package inserts have to be reprinted. Because what we will also learn today is the huge gap between marketing, advertising promises and the lack of information on the test conditions for such value determinations on the one hand and the actual effective thermal conductivities on the other.

Many people don’t even know this: Since pastes and pads are heterogeneous materials, the answer to the question of a blanket thermal conductivity that could be objectively expressed in a single value is quite difficult! Today you can read why this is the case and how to look at the whole thing correctly. Because there are some very bizarre curves that result from structure, temperature, layer thickness, pressure and other factors. And yes, a real rethink is required!

However, as a paying customer of such products, the customer deserves the unvarnished truth, because he is also paying for the many miracle products. And not too little. This is exactly what triggered me years ago and it was finally time to implement the counter-tests in a scientifically accurate, media-effective and mass-market way. Or to put it in a nutshell: We should turn off the tap on all this paste esotericism.

Important foreword: Thanks to everyone involved and a big request to everyone

As a great deal of preparatory work was necessary in the run-up to such a major task and such a purchase must not be made without a plan and an examination of the ROI, a number of well-known and lesser-known contributors were active in the background in the run-up to the project, providing me with insider information, sound practical and manufacturing knowledge and the necessary engineering know-how. First and foremost, of course, these include my colleagues at Berlin-based Nanotest und Design GmbH, a leading manufacturer of such devices, but also Roman Hartung (Thermal Grizzly, insights and practical experience), Andreas Rudnicky (Alphacool, industry samples and insights) and a number of engineers who, for various reasons, do not wish to be named, but to whom I would like to express my thanks at this point anyway. Because one thing is also clear, there are no universal geniuses for all situations and for me, too, some things were completely new and I had to rethink things thoroughly.

As far as my request for test objects is concerned, I am deliberately addressing manufacturers or suppliers and, of course, the community directly. After all, you have to get enough samples to be able to test them extensively in the lab. However, to avoid a flood of duplicate or inappropriate purchases, I would ask you to contact me in advance by e-mail at the known address. I need unopened packs of 3 grams or more (preferably more) and within the best-before date. I cannot and will not test anything else in order to remain objective and fair.

We need to talk about this: marketing promises, fictitious claims and the bitter reality

The business with pastes and pads is booming, especially in times of ever-increasing heat densities and power losses. And it is precisely at this point that I have set myself the goal of providing objective guidance and exposing marketing lies. The profit margins in this business are huge and so the prospect of making a quick buck also brings many suppliers onto the scene whose products are not worth the money or whose products are advertised with properties that are simply not true. Simply checking this is actually impossible, at least it has been until now. When I have tested enough pastes in the foreseeable future, there will also be a publicly accessible online database with the test results, material analyses and pictures.

However, in order to be able to correctly classify, evaluate and recognize the causes of the loopholes of the thermal paste hackers, the existing grey areas and the efforts of reputable suppliers, we must first discuss the topic of thermal conductivity in general on the next page. Because there is no such thing as THE one thermal conductivity. You can read why this is the case and how we proceed after turning the page. And don’t worry, I’ve broken the difficult part down to the bare essentials. So it will be anything but boring, I promise!

First of all, here is a link to the most important basics of heat pastes (and pads) for a better understanding of the connections, as well as a video:

The Ultimate Thermal Paste and Pad Compendium: Application, Ingredients, Manufacturing, Optimization, Aging, Profit Margins and Marketing