Working on a product that needs to seal our air or liquid? You basically have two choices: a gasket or an o-ring. But while these two have similar functions, they perform differently based on pressures and design specs. Here’s the difference between the two.
A gasket is a flat piece of material that sits between to flat surfaces. The gasket’s material—whether neoprene, rubber, silicone or another flexible substance—prevents liquid or air (or sometimes both) from leaking in or out of an area.
Gaskets can be cut into nearly any shape. Many are circular and rounded, but others may be a rectangular, square, triangle, half-circle—virtually any form.
Like the materials used, gaskets can be layered with many different coatings. These layers help with end use and application. Gaskets can be laminated, layered with a pressure-sensitive adhesive, or several coatings combined.
O-rings are circular, ring-shaped pieces that sit in a groove between two (usually cylindrical) parts. The compression of the two parts creates the airtight and liquid-tight seal.
O-rings can be made from many flexible materials, like rubber, neoprene, or polyurethane. While the ring-shape is a staple characteristic of o-rings, the height and thickness of the ring can vary based on your design.
Terminology note: Any o-ring can technically be called a gasket since they prevent the transfer of liquid and air, but while o-rings are a specific shape of gasket, any gasket cannot be called an o-ring.
Based On Your Design or Prototype. If you’re in the beginning stages of the design of your device or equipment, you may be able to use either a gasket or an o-ring. This depends on factors like applications, environment, tolerances and general function. O-rings need a cylindrical groove to sit in while gaskets can perform on a flat surface.
Based On The End Application. Though gaskets can maintain a seal through high and low temperatures and pressures, o-rings can handle extremely highest pressures.
Need help deciding between the two? Let us know. Our engineers and materials techs can help you choose between an o-ring and a gasket as well as decide which material would work best in your product.
O-rings and gaskets are commonly used to create a sealed mating surface between two or more components. They are found in everything from machines and motors to plumbing fixtures and gas pipelines.
When multiple components are joined together, an O-ring or gasket may be installed at the area where they meet. Once installed, the respective component will seal the components so that they don’t leak. While both O-rings and gaskets offer a sealed mating surface, though, they aren’t necessarily the same.
Also known as a packing joint, an O-ring is a type of mechanical seal consisting of a circular-shaped piece of elastomer material. They are designed to create a sealed mating surface that’s resistant to pressure. Some O-rings, in fact, can withstand pressure in excess of 5,000 pounds per square inch (PSI). Even when exposed to severe pressure, O-rings will maintain their integrity while preventing liquids, gas or air from escaping the respective components with which they are used.
Although they are available in a variety of sizes, all O-rings have the same shape. They consist of a looped piece of elastomer material with a hollow center. This circular shape allows O-rings to fit over cylindrical-shaped components, such as pipes and hoses.
A gasket is a mechanical seal consisting of a flat piece of material. By definition, an O-ring is technically a gasket, but not all gaskets are O-rings. O-rings are made exclusively of an elastomer material, resulting in an elastic texture that’s able to stretch and revert back to its natural shape and size without breaking. Gaskets, on the other hand, can be made of any material. Some gaskets are made of an elastomer material. Others, however, are made of harder materials, such as metal. Most automotive engines, for instance, have a head metal gasket that sits between the cylinder head and the engine block.
Gaskets also come in different shapes. O-rings, on the other hand, only come in a circular shape. Many gaskets are designed in a custom shape to fit complex mating surfaces. If a mating surface has four or more components, it may require a custom-shaped gasket rather than a simple O-ring.
Gaskets and O-rings are both used to create a sealed mating surface between two or more components. O-rings are simply circular-shaped gaskets consisting of an elastomer material, whereas gaskets are flat seals consisting of any material or shape.