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.
Which One Should You Use?
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.