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

Gasket Material Design

Have you worked with a gasket and wondered how to improve it? The market does not always align with your exact needs. You might have a gasket material innovation in mind but don’t know how to make that a reality.

You are not alone. There are gasket material manufacturers who used to be in your situation, but they now design and engineer their own materials. They would be great resources to help you out. Depending on your expertise with material constructions, your dream material might already exist. If not, material manufacturers, especially those working with composites, have various options.

If you are interested in proceeding, be ready to answer the following questions:

1. What type(s) of applications are we looking at, and what does it need to seal?

2. What are the operating conditions and temperatures?

3. What do you like/not like about what is currently being used/proposed?

4. What are the flange conditions? Is there sufficient flange load available?

5. What is the design life of the joint? How long does the gasket need to last?

6. What is the target price range? Are we basing on price or performance?

The more specific your answers, the better a material manufacturer will understand your needs and find the best way to meet them. Challenge gasket material manufacturers  by contacting them because everyone benefits from innovation.Request a Call

The Top 5 Things to Remember When Working with Gaskets for Service Applications

Not all gaskets go into brand new applications straight off the production line. There are many gaskets used across the aftermarket, in service operations and in engine rebuilding. Do the same rules and considerations apply to the seal points and gaskets in service applications as they do in OEM manufacturing?

We have put together a list of considerations for those working with gaskets in situations where a gasket is being replaced.

Things to Remember

1. Flange surfaces will change.

Over time and repeated heat cycles, flange surfaces can warp and become distorted, become pitted or corroded, or otherwise become less than ideal. When replacing a gasket, you’ll either need to spend both time and money machining the flanges back to their original state, or use a gasket that can compensate for the irregularities now present. Often, thicker, more compressible gaskets are used in service applications to not only save cost in flange prep, but to make up for material lost in the flange resurfacing process.

2. Replacement products vary greatly.

Service parts are available across an entire spectrum of price and quality. Customers typically are in control of choosing the cost and quality of the parts used in the repair. Parts are available from OEM quality (or better) down to low cost/low quality choices. How long do you want the gasket to last?

3. There are alternatives to the OEM gasket.

While marketing experts will want you to believe that you can only replace a gasket with the same OEM gasket, there are actually quite a few OEM-quality replacements on the market. You can usually save some money and sometimes get better performance.

4. Multiple factors to consider

There are many factors to consider in the process of replacing gaskets. One of which is the installation process itself. What is the torque? What is the sequence? What is the process? Should I include a sealant? Should I retorque it? Is it possible it might be upside down? Are the flanges clean and prepped? The answers to these questions will ultimately help you to settle on the proper replacement gasket, as well as ensure it will perform as expected in your application.

5. Materials / Construction

Have you explored and considered the various material choices for service applications? Which one is best? There are often different constructions of gaskets. Some are single layer materials, some are embossed metal, some are composite laminates. Which is best? Often, the composite designs are the best choice in replacement parts as they best compensate for the factors mentioned throughout this post.

Plenty of Options

Although there are a few extra considerations when choosing a gasket or gasket material for a service application, you may actually find that you have a little more latitude. There are materials out there that have characteristics that excel in these markets. Talk to your trusted gasket material supplier to  figure out which materials will be best suited for your application.

What differences do you find between sealing OEM and service applications?

Metal Tech offers the HT337, which works well in many service applications.Hi-Tex Product Comparison

Jacketed Gaskets: Here’s Why & Where You’d Use One.

Have you ever dealt with applications that require jacketed (or sometimes called double jacketed) gaskets? While the technology may not be as commonly used as others, it is one that definitely has its place in the sealing world.

In today’s post, we’re going to address what they are, as well as why and where you would use one.

The Details

What is a jacketed gasket?

A jacketed gasket has a construction composed of a soft filler material, wrapped by a metal outer layer. Often, this is a two-piece metal construction with a flat layer against the soft facing and a wrap layer that wraps at both sides to form a complete enclosure to encapsulate the filler.

Why would I need a jacketed gasket?

High pressure/high temperature applications often need a rigid shield to resist blowout. Also, the jacketing feature protects the core layer from the conditions.

Where would I use a jacketed gasket?

These gaskets are used in high pressure and high temperature applications where flange areas are limited, but a rigid construction is needed. They are also used in high load exhaust applications, heat exchangers, and pipe flange gasket connections.

Does material selection matter?

Of course it does! The metal layer must be chosen for the environment, with stainless being preferred. Also, the filler material can come from a variety of choices. Often a tanged core graphite or fiber layer is chosen for it’s compressibility yet rigidity in handling and durability for long-term performance.

Meeting Your Needs

It is important to continue to educate yourself on the various gasket technologies available in order to make the smartest choice for your particular needs. As always, your trusted gasket material supplier(s) will often be a great resource for you when it comes time to narrow down your choices. Understanding jacketed gaskets and the applications that they are suited for will make it that much easier to make your decision.

How often do you work with jacketed gaskets?Hi-Tex Product Comparison

Losing Load in a Gasketed Joint? Here’s What You Can Do About It.

There are many reasons why load can be lost in a gasketed joint. Maintaining the desired load can be a challenge at times for a variety of reasons. Today we’re going to cover some of these reasons.

Before we get into it, we want to make sure all of our readers are on the same page and understand what we mean by ‘losing load’. Load is the amount of force (pressure) placed on flanges by applying torque (tightening the bolts) to create the proper seal with the gasket. When you ‘lose load’, your bolts do not retain the torque values applied to them and the gasket will no longer seal properly.

Losing Load

Here are a couple of reasons why you could be losing load, which may help you troubleshoot any issues.

1. Material has creep/relaxation.

Most compressible materials have some level of this which should be considered in the assembly.

2. Improper material selection

Materials exhibit different characteristics in assembled conditions. Be sure to understand the parameters to select the proper choice.

3. Insufficient load

Volts are not torqued sufficiently.

4. Bolt incorrect

Bolts may be undersized or an improper grade for the load required.

5. Environmental exposure or thermal cycles

They can cause materials and hardware to lose load due to compression/recovery, creep/relaxation, bolt stretch/yield, etc.

Find Something That Works

The inability to achieve a proper seal due to loading issues can be a very frustrating issue to resolve. Using some of the information provided above can be a good starting point for you to resolve any of these issues. If troubleshooting seems to point back to a poor gasket material selection or a design flaw that cannot be fixed, talk to your trusted gasket material supplier. They should be able to offer a few suggestions on materials that may be better suited for your application.

What is the root cause of most of your loading issues?Corseal product comparison

The Top 6 Applications Where Composite Gaskets Excel

There are a handful of gasket materials and technologies that are acceptable for a variety of conditions within an application. However, as you venture into specific conditions, those options start to narrow – especially as you get into higher temperature and higher pressure applications.

As an experienced materials manufacturer, when we hear a customer or potential customer start talking about gasketing needs, there are certain applications where we know immediately that metal reinforced composite laminates are a great option. To help you in your planning process, we decided to put together a list of the top applications where these types of gaskets excel (in no particular order).

Look to Composites

1. Exhaust system gaskets

Composite laminates work well in exhaust systems because they tolerate heat and distortion of the flanges. They can also be made with a stainless steel core to resist corrosion and provide long term performance.

2. Aftertreatment system gaskets (DPR, EGR, etc.)

Composite materials perform well here with the rigidity of the steel core for strength and the sealability of the facing material in aftertreatment joints.

3. Manifold gaskets (exhaust/intake)

Graphite laminates are one example of a composite laminate that works well in exhaust manifold gaskets. The material helps to manage heat flow while maintaining a seal.

4. Collector gaskets

Collector gaskets are generally high temperature flanged joints that require a compressible material to seal the joint. Often, composite materials are the first choice here due to their economic advantage and compressible nature.

5. Cylinder head gaskets

Head gaskets have been successfully made from graphite composite laminates since the mid 1980’s. These gaskets perform well as they seal a variety of surfaces while managing heat and providing long-term service.

6. Aftermarket/replacement gaskets (head, exhaust, and intake applications)

Composite laminates are by far the best choice in aftermarket/replacement applications. They provide additional compressibility and conformance to seal against less-than-ideal flange surfaces while compensating for removed material such as surfaces that are refinished. Composites also provide lasting service with their ability to compress and recover in these applications.

Materials that Survive

If you’re dealing with applications that meet any of these conditions, it is important to be aware of the types of materials that are known for successfully sealing them. Once you have an awareness of the general direction you should be going in, talk to a gasket material supplier that specializes in that type of material. Then, you can narrow down your choices to the one material that is best suited for the conditions it will need to withstand.

What are the other applications where you prefer metal reinforced composites?

Aftertreatment Systems Material Guide