Not All O-Rings Are Alike: Knowing The Materials For Different Applications

O-rings are a lot more varied than most people realize. Most important of all is their variety of applications. They can be used as seals in a wide range of ways — including gasket seals, dynamic seals and rotary seals, among others — in industrial, manufacturing and other business use cases. Given their breadth of uses, it should go without saying that not all o-rings are alike. Here, we look at how they differ from one another when it comes to their material composition and their suitable applications.

Rubber Compounds

While the specific materials are all quite different, o-rings are made of rubber-like elastic compounds. But, of course, there are many different types of rubber, including natural rubber, silicone, neoprene and flurocarbon, and each of these different elastomeric compounds has its own attributes that help govern how it can be best used.

Some have excellent elastic recovery (the ability to return to their original shape), some are more resistant to deterioration and some are able to withstand extreme temperatures. After understanding all these strengths and weaknesses, end users can come to understand why different materials are ideal for different use cases.

Automotive and Transportation

The automotive and transportation world uses a wide variety of o-rings. Neoprene (also known as chloroprene) is always among the top choices because it was created as a synthetic, oil-resistant substitute for natural rubber that happens to also have outstanding physical toughness.

Ethylene or acrylic (under the brand name Vamac) is another popular material for sealing in automotive applications, especially in power steering and automatic transmission systems. It is also known for its top-tier heat resistance and low permeability to gases.

Aerospace and Aviation

Even more demanding than the automotive world is the aerospace and aviation sector. Throughout the history of aviation, engineers have sought compounds capable of offering both high-temperature resistance and chemical resistance. In modern times they now often turn to o-ring seals made of flurocarbon (branded at Viton).

Fluorosilicone is another common choice, largely because it combines the high- and low-temperature stability of silicone with the oil and solvent resistance of fluorocarbons. This makes it an ideal solution for static sealing applications in aerospace fuel systems, for example.

Food and Beverage

While people tend to expect all industries to immediately use modern synthetic materials, natural rubber still has a place when it comes to seals in the food and beverage world. Though it was once the only game in town — and thus the only compound used for o-rings — natural rubber has managed to maintain its position here.

Then again, there is also nitrile (or Buna-N), the most widely used polymer by the seal industry across the board. Its versatility and price means it is widely used throughout virtually all industries, and it can be compounded for use in various food applications approved by the FDA.

Wide Application of O-Rings

While it’s possible to go on almost indefinitely showcasing all the many o-ring materials, the key is to understand just how many different types of rubber compounds there are and why each serves specific applications. What works perfectly in some cases will fall short in other uses.

Chances are, even if you are an industry veteran, you may not have realized the scale and scope. While automotive and aerospace applications often prioritize temperature resistance, for instance, the food world can still benefit from the attributes that natural rubber is still capable of providing.

Beyond this, the major takeaway is just how many materials and applications there are for modern o-rings. While they definitely are not all alike, they do all have their place.