By Norman Quesnel
Senior Member of Marketing Staff
Advanced Thermal Solutions, Inc. (ATS)
As you may already know, TIMs – thermal interface materials – are not especially easy to remove from heat sinks. But the needs to do so are common: repositioning the sink, switching to a better performing TIM, replacing components, etc.
Most of today’s TIMs are bonded to heat sink surfaces with a pressure-sensitive adhesive layer. The rest of the TIM may be an elastomer filled with thermally conductive particles. Bonding pressure, such as from clips and screws increase the thermal performance, but the result can be a TIM that’s hard to remove from the heat sink surface.
Another kind of TIM is thermal grease, which is an excellent heat conductor but is inherently messy. This must be accounted for when removing thermal grease from a heat sink surface.
With the right tools and some patience, a heat sink can have its TIM removed completely. The approaches are similar for removing different kinds of TIMs.
Removing Thermal Tapes
Double-sided thermal interface tapes provide exceptional bonding properties between components and heat sinks. For many applications they remove the need for mechanical fasteners to secure the sink to the component.
Here we are showing the removal of Parker Chomerics Thermattach T412 tape from a heat sink. The T412 tape has aluminum mesh carrier which helps improve heat transfer. The aluminum also helps keep the TIM together when it’s removed.
Use a razor blade, but don’t gouge the aluminum because if it makes the surface uneven that will negatively impact heat transfer. Start at one corner, try to lift the TIM slightly the razor blade, be careful not to cut yourself.
Next, put the heat sink (upside down) on a paper towel. This is mainly to protect the fins of the heat sink from getting scraped. Then, use a putty knife with a flexible blade, or a plastic scraper or something similar with a non-gouging edge to help remove the rest of the TIM.
Push the scraping edge carefully forward under the TIM corner, while pulling the TIM slightly up. While you are starting to lift the original TIM corner from the surface, you can start doing the same on another corner. And if continue to work at it from different angles eventually you can get the TIM off.
If there is TIM residue left over on the heat sink surface, you can use a lint-free cloth and a solvent to wipe it clean. The solvent should be something that won’t damage the finish on the heat sink. Here we used isopropyl alcohol. You may have to repeat this several times to get everything off and you have a clean surface.
Removing Phase-Change Materials
Phase-change materials (PCM) can be removed with similar steps as with thermal tapes. These images show the removal process using a maxiFLOW™ push pin heat sink from Advanced Thermal Solutions, Inc. (ATS).
Start with sharp, clean razor blade because a plastic scraper’s edge isn’t fine enough to penetrate cleanly under the TIM. Be sure the razor blade is straight to minimize the risks of nicks to the heat sink surface. The TIM manufacturer’s data sheet recommends using a razor blade to remove the phase change TIM. In this demo, the TIM is Chomerics T766 PCM. Slowly work the razor blade edge under the TIM, be careful of your fingers.
After a lot of use phase change materials can be hard to remove compared to new pieces. Use the razor under different corners. Go slowly until you get all the material off. You will be left with some PCM residue on the heat sink surface.
You can put a small amount of isopropyl alcohol on the surface and use this as a lubricant and go back with the razor blade to get a close shave on that surface to remove much of the remaining TIM residue.
When your sink’s surface is nearly clean, get a lint free cloth or a wipe. With some alcohol and with a bit of rubbing you should be able to remove the rest of the phase change material.
Removing Thermal Grease
Here we start with a heat sink with thermal grease on its mounting surface.
Start by removing as much grease as possible using a dry cloth or paper towel. You should be able to get most of the grease off this way.
Then, for the leftover grease residue, use a lint-free cloth or rag with some alcohol or another type of solvent that won’t eat away at the heat sink’s anodized surface. With a little elbow grease, you should be able to get the surface clean.
Note that If you’re going to be doing a lot of handling of thermal greases and solvents, it’s advisable to wear protective gloves.
For more information about Advanced Thermal Solutions, Inc. (ATS) thermal management consulting and design services, visit https://www.qats.com/consulting or contact ATS at 781.769.2800 or ats-hq@qats.com. To register for Qpedia and to get access to its archives, visit
https://www.qats.com/Qpedia-Thermal-eMagazine.