While standard O-rings are frequently used across many manufacturing and industrial industries, their versatility can make it difficult to choose the correct O-ring material. O-rings possess a wide array of applications and are composed of a large variety of materials. Thus, it can be helpful to understand the different options and the pros and cons of each.

Why O-Rings Are A Smart Choice

O-rings are fundamental to industrial pressure systems. Although they appear deceptively simple, O-rings—both large and small—play a critical and complicated function in contemporary machinery’s workings. O-rings work by creating an extremely durable seal when compressed by two distinct parts.

Consequently, the seals can hold up to large amounts of pressure. Common O-ring varieties include:

 

Buna-N (Nitrile) O-rings

The Buna-N is considered a standard O-ring and general-purpose seal. Pros include an ability to withstand abrasive activity and the fact that it’s tear-resistant. Moreover, the Buana-N can handle frigid temperatures in the range of -54 to -149 degrees Celsius.

This standard O-ring is compatible with hydraulic fluids, as well as petroleum and water. However, this product is not advised for halogenated hydrocarbons, phosphate ester, ketones, nitro hydrocarbons, or automotive brake fluid. They are both weather and ozone-resistant. However, compounding is known to boost their strength overall.

Silicone

Silicone is considered a superior rubber sealing product, commonly used in petroleum, steam, and water situations. Silicone O-rings have undergone rigorous testing and can stand up to shallow temperatures when exposed in small increments. Silicone performs less well in the area of tensile strength and abrasion resistance. It also displays inferior tear resistance. Consequently, this product is better suited for use in static machinery.

Neoprene O-rings

These rings fall under the category of all-purpose elastomer. These rubber O-ring seals possess many benefits, including being highly weather-resistant. These characteristics make Neoprene suitable for use in situations where other materials parts fail to perform. Additionally, this product resists flex cracking. It also absorbs well and displays superior resistance. Neoprene is a popular choice for air conditioning and refrigeration units. However, this product can cause mild allergic reactions in some people.

PTFE

PTFE is known for its low absorption and non-permeability, as well as its chemical alertness. This product also tolerates abrasion well and is corrosion-resistant, making it an extremely versatile O-ring choice. Moreover, it can stand up to a wide range of temperatures—between -73 and 260 degrees.

Polyurethane O-Rings

These rubber O-ring seals get top marks for all-around strength, as well as extrusion and superior abrasion resistance. However, they don’t perform well in situations where heat resistance or positive compression is required. These rings can often be found in valves, firearms, and cylinders, to name a few.