Let us start by saying:
All gaskets are seals, but not all seals are gaskets.
And yes, we know that they are very often grouped together and do indeed have similar functions; however, they are different, both in their characteristics and use.
With the automotive industry and electronics sectors being the largest consumers of gaskets and seals, it’s important to understand the difference between each, and in this post, we look further at seals and their function within applications as well as metallic gaskets and where each of these components “fit” within equipment and parts.
If you have any specific questions relating to seals and gaskets, please get in touch with a member of the SSP team today, we’d be happy to help.
What is a gasket?
Gaskets are a type of seal, placed between two static parts to create a robust joint between two flanges, which, when compressed, the gasket fills the gap to create a seal.
Often, ring-type joint gaskets are used to fill irregularities and can be manufactured from a range of materials that can be cut to fit the component.
Types of gaskets can include metallic gaskets, ring-type joint gaskets, and kammprofile gaskets, with gaskets also helping to reduce vibration and noise at the connection.
What is a seal?
Seals ultimately form a dynamic barrier, preventing leaks and contamination such as dust, dirt, and water.
They are round in shape, fitting within the groove of dynamic surfaces such as rotating shafts, engine parts, and pumps. Seals are typically used in pipe joints, hydraulic systems, fuel systems, aircraft, and HVAC systems.
There are various types of seals such as rotary, conventional, O-rings, mechanical, and valve stem seals.
Static versus dynamic
The key difference between a gasket and a seal is the applications in which they are suitable.
For example, gaskets are used for static applications where the gasket is used to close the gap between two parts that are static and do not show any relative motion.
In comparison, seals are more suitable for dynamic applications and are typically used to fill the gap between two parts that show sliding or relative motion.
Gaskets are used to seal against dust, moisture, and chemicals, forming a seal through compression.
In comparison, seals are used to prevent leaks from oil and grease, keeping out contaminants such as dust, dirt, and water. Seals often include a rubber sealing lip and metal covering for additional stability.
Gasket vs seal
| Gasket | Seal | |
| Motion | Suitable for static applications | Suitable for dynamic applications |
| Materials | Rubber, Silicone, EPDM, Neoprene, Polyurethane | Polyurethane, Nitrile Rubber, Polytetrafluoroethylene, Thermoplastics |
| Typical failure mode | Leak occurs due to loss of compression, material degradation, or incorrect installation | Material loses its elasticity, and deformation leads to leaks |
| Replacement | Gasket needs to be replaced with a new one | Both the seal and the bearing must be replaced |
Choosing gaskets and seals
When choosing the right gasket and seal for your application, you will need to take into consideration whether you require a static or dynamic sealing solution, as well as understanding:
- Fluctuations in temperature
- Changes in pressure
- The fluid or gas you are sealing
- The environment the gasket or seal will be exposed to
- Compliance and regulatory standards.
What happens when a seal or gasket fails?
If a gasket breaks down, you will need to replace the existing gasket with a new one.
However, when a seal breaks down, you will need to replace both the seal and the bearing with new ones.
This can make seals more challenging, however, with proper installation and care and maintenance, seals do provide a long lifespan.
Gasket supplier UK
Understanding the subtle differences between gaskets and sealants can prove to be essential for providing a robust sealing solution.
At SSP, we stock a range of seals and gaskets to suit various applications across a wide range of industries. Ranges such as:
- Soft cut:
- CNAF
- Graphite
- PTFE
- Rubber
- Mica
- Cork, and
- Paper
- Metallic:
- Ring type joints
- Spiral wound
- Kammprofile, and
- Metal-clad
Visit our product page to find out more.
To find out more and to see how we can help you find the right seal or gasket for your application, visit our product pages, or speak to a member of the SSP team today; we’d be happy to help.
FAQ
Q: Is a gasket a seal?
A: A gasket can be a type of seal, but a seal is NOT a gasket.
Q: Can you use a gasket instead of a seal?
A: No, you can’t use a gasket instead of a seal due to the difference between static and moving parts.
Q: What is a seal made of?
A: Seals are round in shape (O-ring most common), and are typically made of polyurethane, nitrile rubber, thermoplastics, and polytetrafluoroethylene.
Q: Gasket or seal?
A: This is dependent on whether the application and the two mating parts are static or rotating with movement. Opt for a gasket for static applications, and a seal for dynamic applications; consider a static seal vs. a dynamic seal.
