The following illustrated step-by-step guide shows an example of how to clean a GPU heatsink professionally, cut a PTM pad to size and apply it correctly. All the technical details and practical recommendations explained above are taken into account. The images shown serve to illustrate the process and are based on the use of a classic Honeywell PTM 7950, whereby other pads are applied in the same way in principle.
Step 1
The cooler after removing the GPU and circuit board shows a completely baked PTM layer. The material has melted and spread evenly according to the heat distribution. The residues are typical of a phase-changing pad after prolonged thermal stress. It is now important to remove the material completely and without damaging the structure, without scratching the metal surface or spreading impurities.
Step 2
As already explained, it is essential to first pre-clean mechanically with a dry, lint-free cloth or suitable cotton swabs and remove the debris before selectively using isopropanol.
Step 3
After cleaning, the surface is completely free of residue again. A cut pad is now positioned on a trial basis. This allows precise adjustment of the appropriate cut. It is important that the surface is completely covered, but that no surrounding mechanical supports or edges are covered. A slightly oversized pad can be precisely adjusted afterwards, but does not have to be. If the pad is cooled briefly beforehand, it can be cut even more precisely and handled better, as described above.
Step 4
The pad is aligned as a test to determine its final position. The protective film on both sides remains untouched for the time being. This makes handling easier and prevents sticking during adjustment. It can be seen that the pad is positioned on the mechanically rougher radiator surface – as explained in the previous text, this is generally preferable for reasons of better adhesion and installation safety. Adhesive tabs are also attached to make it easier to remove the film using this peel-off aid.
Step 5
Now remove the pad from its backing, leaving one of the two protective films in place for the time being. This handling allows the pad to be placed securely without sticking or accidentally folding. It is important that no stresses are introduced into the material during removal. However, the pad must be applied at room temperature to ensure that it sticks well.
Step 6
The pad is now positioned by carefully placing it on the intended area. You can use a small plastic tool or a thin spatula to help you apply the pad flat without contact with the fingertip. Important: The surface must be completely dry, dust-free and grease-free. Residual moisture from isopropanol must have completely evaporated in order not to impair adhesion and thermal coupling. The pad is pre-fixed by lightly pressing it down. This step should be carried out at an angle of less than 45° so as not to lift or stretch the pad. If the pad has been cut correctly, it will fit exactly into the intended area and will adhere without tension. An alternative, but very practical way to press the pad on securely without finger contact is to use a small plastic pick or tool with rounded edges. This allows the pad to be applied over a wide area without creating pressure points. This ensures that the material has equal contact with the surface in all areas.
Step 7
A flat plastic spatula is now used to lift off the remaining protective film on the top. Caution is also required here: The movement should be slow and even so that the pad does not peel off or warp. As already mentioned, the complete removal of both films is essential to ensure effective thermal coupling.
Step 8
In this close-up, the final protective film is removed cleanly. The pad is now ready for installation. It has been applied completely flat and tension-free. An uneven or damaged surface should have been noticeable at this stage. The material shows an even structure without inclusions or air bubbles – a sign of clean processing. The circuit board can now be placed back on the cooler after the cables have been connected. The clamping cross is then screwed in place, always alternating with the long sides of the GPU.
Step 9
The finished graphics card is tested in a test setup under load conditions. FurMark is used here to force a controlled burn-in of the GPU and thus the thermally activated transient phase of the PTM material. As described in the introductory texts, the pad requires several load cycles with temperatures above the transition temperature (approx. 50 °C) in order to develop its final thermal conductivity. This step is essential if realistic performance or stability measurements are expected.
Interim conclusion
The correct application of phase-changing TIMs such as the PTM 7950 requires more than simply sticking on a pad. Careful cleaning, precise cutting to size, controlled placement and the complete removal of both protective films are just as crucial as targeted thermal transient response under a defined load. The sequence shown here illustrates how a technically clean and repeatable application can be achieved with relatively simple means – without improvised methods or error-prone instructions.
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