A thermal paste is a thermally conductive chemical compound consisting of a polymerizable liquid matrix and a large volume of insulating filler loading (as high as 70-80% by mass) which is used as an interface between heat sources and heat sinks like high semiconductor devices.
It eliminates air gaps from the interface to increase heat transfer, improves the heat coupling between different components, and drains heat from electrical resistance in semiconductor devices.
How does thermal paste work
A Thermal paste is a material that is applied to an object, typically the base of a heat sink, to improve thermal conductivity between two surfaces.
Thermal conductivity is the rate at which heat moves across the surface of an object. It’s important because it determines how fast an object will cool down or warm up.
Electronic components can be sensitive to temperature fluctuations because they need to maintain a certain level of performance in order to function properly. Thermal paste fills in microscopic air gaps that would otherwise impede the ability of cooling fans or heatsinks to dissipate heat away from components, making them function more efficiently.
It can be hard to measure how much better one thermal paste is than another without testing them side-by-side in controlled conditions.
The role of thermal paste in computer processors is to provide a connection between the processor and cooler for transferring heat away from the processor. Thermal paste does not reduce temperatures by itself but instead provides a pathway for heat to escape from the processor as quickly as possible.
Can you use toothpaste as a thermal paste?
While you can use some toothpaste as a thermal paste (because they give out the type of thermal conductivity needed), you can’t use some others.
There are various types of toothpaste and their level of thermal conductivity also differs.
While on the lookout for toothpaste in place of a thermal paste, most people tend to consider the following factors:
- How well it conforms to uneven surfaces, heat sinks, and fills the gap?
- How it is consistent over the temperature range that’s required?
- How well it resists flaking or drying out over time?
- Whether it insulates electricity or not?
How long should thermal paste sit?
Thermal pastes actually have shelf lives and they can also go bad. Most manufacturers estimate a shelf life of 2-3 years for thermal pastes.
People often wonder if thermal pastes expire. Yes, they do and this is depending on the brand type and mode of application of the thermal paste.
It will eventually dry out, begin to crack, and eventually lose its effectiveness. If you fail to reapply thermal paste, your computer might overheat and this will cause damage to many parts of your computer system including the CPU.
How to tell if thermal paste is bad?
You could spread some out on a sheet or surface that’s metallic to check whether it’s smooth and consistent.
if the thermal paste turns out to be watery, you should dispose of it away.
Most times, the thermal paste shouldn’t be replaced more than once every year unless the temperature of your CPU is rising really high.
To tell if the thermal paste in your computer is bad, you should look out for:
- Excessive temperature rise in the processor or graphics chip
- Computer turning off itself or throttling back to performance
- Dust clog in fans or heatsinks
Can You Reuse Thermal Paste?
However, the thermal paste can be reused by reseating the heat sink without applying new thermal paste.
It will still provide sufficient heat transfer to prevent damage. The problem with the paste is that it’s supposed to fill the gap created by microscopic valleys and pits once the heat sink and the CPU get in close contact with each other. It’s advisable to make sure the old thermal paste isn’t contaminated with dust, dirt, or any other thing that will prevent the heat sink and the CPU from sitting in contact with each other.
It can be reused many times by scraping off the excess thermal paste and applying it again, but after some time, the performance of thermal paste starts deteriorating.
Can you use old thermal paste?
The answer to this question is yes, but it depends on how old the thermal paste is.
You can reuse a tube of thermal paste as long as it is not dried out.
It is best to use fresh thermal paste. However, if you do have used thermal paste, there is no harm in using it again.