Do I Need an O-ring or a Gasket?

How well do you understand the differences between o-rings and gaskets? Can you readily identify situations where each type of seal should be used? There are specific situations where each technology is needed because they are designed for completely different conditions.

Today, we thought we’d dig a little deeper into gasket vs. o-ring.

Gasket vs. O-ring

What exactly is an o-ring?

If you are envisioning a rubber ring, you are right! However, they aren’t quite that simple. An O-ring is a precisely molded shape with a specific profile to fit into a specific channel or groove. These profiles can be various shapes and the polymer (type of rubber) can also vary greatly. Infinite formulas can be made to address specific sealing situations.

Where and how are they used?

O-rings are known for their ability to seal extremely high pressures. Here is a short list of some of the more common places where you would find them.

    • Hydraulic seals
    • Pipe joints
    • Fluid seal points in equipment
    • Oil seals
    • Fuel systems

How does this differ from gaskets?

When you move away from engineered seals like o-rings, the next technology to use in the sealing family is a gasket. These typically require a flat flange and a bolted joint. Gaskets are by far the most versatile seal, with different shapes, materials, coatings, methods, etc. Depending on the type of material chosen, they can seal at a wide range of temperatures and pressures. Composite (metal reinforced) materials provide some of the strongest heat and pressure resistance (as far as gaskets go) in the market today. For more information about these materials, view our post What Is a Metal Reinforced Gasket and Why Do I Need One?

How do gaskets with rings compare to an o-ring?

Some of you may know that adding a ring to your gasket design adds another layer of protection against increased pressure. Rings make a good gasket even stronger. View our post Should I Put a Ring On It? (Your Gasket, That Is) to get a better understanding of this technology. In light of our discussion today regarding o-rings, the next logical question is how does a gasket with a ring compare to an o-ring? The simple answer is that the O-ring requires a channel or groove in the flanges, while a gasket can perform with a simpler, flat flange. O-rings are typically used when pressures are higher, with the channel present to prevent blowout.

Choose Your Technology

Once you truly understand all of the engineering behind all of the various sealing technologies, the decision on what should be used is very clear. Until then, talk to your contacts in the sealing industry to better understand what your options are for a specific application.

Until next time!Hi-Tex Product Comparison