The Difference between Gaskets and Seals

Gaskets and seals are components that are often conflated with one another due to the similar roles they play in creating seals. Despite this, there are certain differences between the two that are important to consider when one is searching for the right fit for their project. While gaskets can optimally seal connections between the flat surfaces of components or flanges, seals are used to seal rotating engine parts, shafts, and pumps. In this blog, we will provide a brief overview of gaskets and seals, allowing you to better understand their differences and roles.


As a mechanical seal, gaskets may be implemented in an assembly to fill the gap between two or more mating parts, then compressed to ensure that no fluids leak to or from objects. As a static seal, gaskets are most beneficial for the fact that they are deformable, allowing them to easily accommodate less-than-perfect mating surfaces that may have irregular gaps. Gaskets can be manufactured from various materials, the most common examples being viton, neoprene, nitrile, pure gum rubber, EPDM butyl, and SBR. If a higher amount of compression is needed, then alternative materials can be used such as cork and rubber, graphite, closed cell sponge, PTFE, non-asbestos, vegetable fibers, and more.

Due to the role that they play, and the method in which they are installed within an assembly, gaskets are a one-time use item that should be replaced regularly. Generally, the gasket should be replaced every time that the assembly is taken apart, allowing for an optimal seal to be established upon reassembly. With their various uses and capabilities, gaskets typically find implementation in industries such as oil and gas, electric generation, pulp and paper, and transportation.


As compared to gaskets, seals are best fit for assemblies that rotate, finding use for engine parts, pumps, and shafts alike. Such seal types are often molded or machined, their shape being flat and round. This is in contrast to the varying designs of gaskets that allow them to fit into irregular gaps. For seals, the common design is to have an outer ring made of metal that nests over a rubber inner circle. As the inner circle is tilted to a small degree, the seal is provided with a lip. This ensures that any fluids that pass the first edge of the seal are blocked. Due to their method of attachment, one should always be careful to ensure that the seal is placed in the right orientation, as a backward seal can easily lead to major leaking.

Seals can be used for numerous assemblies and applications, often implemented within hydraulic systems and other equipment that may face leaking. In some instances, seals may even be placed with a bearing to reduce operational noise while guarding the component from leaking. Generally, seals must be replaced every time they break down, and will often require the replacement of other parts such as the bearing as well. If you find yourself in need of replacement seals or gaskets for your particular project, look no further than Aerospace Sphere.

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