How to use and apply conductive compounds

Many years ago it was an option to use a thermal compound but now with high speed electronics it is necessary to use these compounds.  Thermal compounds which are also called Thermal pastes, are meant to fill voids on the surface of electronics interface and the heat sinks. actually thermal paste should replace the air in these voids. because air is a bad conductor of heat. The surface of electronics and heat sinks usually polished and looks smooth and perfect but in fact there are many microscopic voids on these surfaces which allow air to trap and cause to negative impact on heat transfer between electronics and heat sinks. That is the reason we need to use thermal compounds and we only need a thin layer of these thermal compounds just only enough to fill those microscopic pores. Because the thermal paste is not as conductive as metal (thermally conductive), and that is why we need to use as small amount as possible. So the question is how to apply a really thin and even  layer of thermal paste which is not bleeding?

First you need to prepare the surfaces. clean the surface of the CPU or any electronic device and CPU cooler or heat sink with a cotton dampened by isopropyl alcohol. You can also polish the surfaces by sanding to make them more smooth.

Now you can apply the thermal paste. Applying the thermal paste is very important. Depending on the kind of electronic and the surface area of the interface, and the choose of user, there are several methods to apply thermal pastes. Here we explain the most popular and effective methods. If the surface of CPU or GPU or any other device is circular in shape, place a small drop of thermal paste on it. the size of drop should be smaller than a rice grain. for circular coolers you don’t need to spread the paste, the even pressure of cooler will spread it evenly and smoothly. Therefore you can now install the heat sink.  heat sink installation should be done with even pressure from all sides. after installation do not remove the heat sink (for checking the paste), if you remove you have to do all the procedure from beginning. Now you can plug in the fan wire socket to the motherboard.

For square shape processors it is a little more difficult to apply, and by above method the paste will not fully cover the surface. You can apply the thermal paste by one of below methods:

crossed lines: you should apply two crossed line like “X” on the center of surface. And the length of each line should be on-third of the  width of processor’s surface.

parallel lines: you should apply two thin lines on the surface, the lines should be parallel and each line should be placed on the one-third of width of the surface. And the length of each line should be on-third of the  width of processor’s surface.

spreading the thermal compound: this method is a little more difficult but more effective and more popular. Place a small of amount of thermal paste on the surface of processor. Now you can use a plastic cover to spread the paste evenly by your finger. Ensure to apply a thin layer and cover all the surface. It is very important not to apply too much paste, the paste should barely hide the metallic surface of the processor. you can also use a card to spread the paste.

Now you can install the heat sink. For either of line methods you should apply even pressure from all sides to spread an even thin layer of paste on the surface.

But for spreading paste method, in order to prevent air bubbles formation, you should install the heat sink at a slight angle.

Now you can reconnect the fan.