What paste to be used on heat sink?

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What is Heatsink paste?

Heatsink paste, also known as thermal paste, thermal compound, or thermal grease, is a material that is applied between a heatsink and the component it is cooling. The purpose of heatsink paste is to fill in any microscopic gaps or irregularities between the two surfaces, allowing for better thermal conductivity and more efficient heat transfer.

Types of Heatsink Paste

There are several different types of heatsink paste available on the market, each with its own unique properties and benefits.

Silicone-Based Paste

Silicone-based heatsink pastes are some of the most common types available. They are easy to apply, have a relatively long shelf life, and provide good thermal conductivity. Silicone-based pastes are also non-conductive, making them safe to use on electronic components.

Pros Cons
Easy to apply Can dry out over time
Non-conductive Not as effective as other types
Long shelf life

Ceramic-Based Paste

Ceramic-based heatsink pastes are another popular option. They offer excellent thermal conductivity and are also non-conductive. Ceramic-based pastes are often more stable than silicone-based pastes, meaning they are less likely to dry out or separate over time.

Pros Cons
Excellent thermal conductivity Can be difficult to apply evenly
Non-conductive More expensive than silicone-based pastes
Stable over time

Metal-Based Paste

Metal-based heatsink pastes, such as those containing silver or aluminum, offer the highest level of thermal conductivity. However, they are also electrically conductive, which means they must be applied carefully to avoid short-circuits.

Pros Cons
Highest thermal conductivity Electrically conductive
Can be difficult to apply evenly
Most expensive type of paste

Carbon-Based Paste

Carbon-based heatsink pastes are a newer type of thermal compound that offer excellent thermal conductivity and are electrically non-conductive. They are often used in high-performance applications where maximum heat transfer is required.

Pros Cons
Excellent thermal conductivity Can be difficult to apply evenly
Non-conductive More expensive than silicone-based pastes
Stable over time

How to Apply Heatsink Paste

Applying heatsink paste is a relatively simple process, but it is important to do it correctly to ensure optimal performance.

Step 1: Prepare the Surfaces

Before applying heatsink paste, it is important to ensure that both the heatsink and the component it will be cooling are clean and free of any dirt, dust, or old thermal compound. Use a lint-free cloth and isopropyl alcohol to clean both surfaces thoroughly.

Step 2: Apply the Paste

There are a few different methods for applying heatsink paste, but the most common is the “pea method”. To use this method, simply place a small amount of paste (about the size of a pea) in the center of the component.

Step 3: Attach the Heatsink

Once the paste is applied, carefully place the heatsink on top of the component, making sure it is centered and making good contact with the paste. Apply gentle pressure to the heatsink to spread the paste evenly between the two surfaces.

Step 4: Secure the Heatsink

Depending on the type of heatsink and component you are using, you may need to secure the heatsink in place using screws, clips, or other fasteners. Refer to the manufacturer’s instructions for specific guidance on how to properly secure your heatsink.

Factors to Consider When Choosing Heatsink Paste

When choosing a heatsink paste, there are several factors to consider to ensure you select the best option for your needs.

Thermal Conductivity

The thermal conductivity of a heatsink paste refers to its ability to transfer heat. Pastes with higher thermal conductivity will be more effective at dissipating heat away from components.

Heatsink Paste Type Thermal Conductivity (W/mK)
Silicone-Based 0.5 – 2.0
Ceramic-Based 2.0 – 4.0
Metal-Based 4.0 – 8.0
Carbon-Based 4.0 – 10.0

Electrical Conductivity

Some heatsink pastes, particularly metal-based pastes, are electrically conductive. This means they can cause short-circuits if they come into contact with exposed electrical components. If you are working with sensitive electronics, it is important to choose a non-conductive paste.

Ease of Application

The ease of application of a heatsink paste can vary depending on its composition and viscosity. Some pastes are more runny and easier to spread, while others are thicker and more difficult to work with. Consider your own skill level and the tools you have available when selecting a paste.


The durability of a heatsink paste refers to how well it holds up over time. Some pastes can dry out or separate, reducing their effectiveness. Look for pastes that are designed to be stable and long-lasting.


Heatsink pastes can vary widely in price, from a few dollars to over $20 for a small tube. While it may be tempting to choose the cheapest option, keep in mind that higher-quality pastes may offer better performance and durability, potentially saving you money in the long run.


How much heatsink paste should I use?

When applying heatsink paste, a little goes a long way. A pea-sized amount is usually sufficient for most applications. Using too much paste can actually reduce its effectiveness by creating air pockets between the surfaces.

Can I reuse heatsink paste?

It is generally not recommended to reuse heatsink paste. Once a paste has been applied and the heatsink has been attached, the paste will have spread out and filled in any gaps. Removing the heatsink and trying to reuse the paste can introduce air bubbles and contaminants, reducing its effectiveness.

How often should I replace heatsink paste?

The lifespan of heatsink paste can vary depending on factors such as the type of paste, the environment it is used in, and the amount of heat being generated. As a general rule, it is a good idea to replace heatsink paste every few years or whenever you notice a decrease in cooling performance.

Can I use other materials instead of heatsink paste?

While there are some alternative materials that can be used in place of heatsink paste, such as Thermal Pads or graphite sheets, these are generally not as effective at transferring heat. Heatsink paste is specifically designed for this purpose and is the recommended option for most applications.

Do I need to use heatsink paste if my heatsink comes with a pre-applied thermal pad?

Some heatsinks come with a pre-applied thermal pad that is designed to take the place of heatsink paste. If your heatsink has one of these pads, you do not need to apply additional paste. However, keep in mind that these pads may not offer the same level of performance as a high-quality heatsink paste.


In conclusion, heatsink paste is an essential component in any cooling system that relies on heatsinks. By filling in the microscopic gaps between the heatsink and the component it is cooling, heatsink paste allows for more efficient heat transfer and better overall cooling performance.

When selecting a heatsink paste, it is important to consider factors such as thermal conductivity, electrical conductivity, ease of application, durability, and price. By taking the time to choose the right paste for your needs and applying it correctly, you can ensure that your electronic components stay cool and running smoothly for years to come.