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What Are Silicone Rubber Gaskets?
Gaskets are mechanical seals used to fill in the spaces between two mated surfaces. They are engineered to prevent fluids (gas or liquid) from leaking out of or into the system between the two surfaces while under compression. In some assemblies, they serve as a barrier that keeps two components separated to protect them against friction damage.
These sealing devices can be made from a wide range of materials depending on the requirements and restrictions of the application. One of the most commonly used is silicone rubber. It exhibits many advantageous characteristics that make it suitable for various industrial and commercial applications. For example, its excellent resistance to extreme temperatures, ozone, and ultraviolet (UV) radiation enables it to be used in outdoor environments without fear of premature degradation.
Types of Silicone Gasket Materials
Silicone rubber comes in many types, grades, and forms to suit different applications. The ones commonly used to make gaskets are:
- Solid silicone rubber. This material has a dense molecular structure. It can have low or high durometers. The former is suitable for seals with low closure force requirements, while the latter is suitable for seals with high closure force requirements.
- Sponge silicone rubber. This material has a cellular structure that provides some cushioning and padding properties. It is available in two basic types: open-cell and closed-cell. Open-cell sponge silicone has interconnected pockets that allow air, chemicals, and water to pass through when it is uncompressed. Closed-cell sponge silicone has pockets that are filled with nitrogen to prevent anything from passing through it.
- Foam silicone rubber. This material offers flame resistance. It is available in soft, medium, firm, and extra-firm grades and open-cell, closed-cell, and combined open-cell/closed-cell variations.
- Liquid silicone rubber (LSR). This material is a two-part material system that must be mixed and heat cured before use. It offers fast and inexpensive molding operations, clean curing operations, and low durometer options.
These silicone rubber gasket materials can be made in various grades, such as FDA-compliant, UL-compliant, and MIL-SPEC, and shaped into sheet, roll, and other standard or custom profile forms to meet different industry and application requirements.
Why Use Silicone Rubber?
Silicone rubber exhibits many properties that make it ideal for use in gaskets, such as:
- Resilience over a broad temperature range. Silicone rubber is resistant to chemicals, moisture, oxygen, ozone, and sunlight, and it maintains these qualities in both extremely low and extremely high temperatures.
- Resistance to permanent compression set. Silicone rubber will return to its original shape after being subjected to compressive forces.
- Availability in various durometers, colors, and specialty grades. Silicone rubber comes in numerous hardness levels, colors, and grades, so it can be used for many applications.
Common Applications of Silicone Rubber Gaskets
Some of the industries that commonly rely on silicone rubber gaskets include:
- Food Processing
Contact Us for Silicone Gasket Solutions
Want additional information on silicone rubber gaskets? Ask the experts at Mercer Gasket & Shim! We’ve supplied gaskets and other industrial products for over 100 years. We have what it takes to answer or address any questions or concerns you may have about these products.
If you need standard or custom gaskets, we’ve got you covered. Our extensive selection of gasket materials enables you to choose the best material for your application. Additionally, as an ISO 9001:2015 company, you can depend on us for quality products and services. Our standard is 100% defect-free products delivered 100% on time.
Contact us today to learn more about our capabilities. Request a quote to start your order.
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While gaskets and O-rings serve a similar purpose of sealing out air or liquid, the two are designed for different situations and vary in appearance. Here, the team at Mercer Gasket & Shim will explain the differences between these sealing solutions to help you determine the best one for your application.
What Are Gaskets and O-Rings?
Gaskets are flat pieces of material used to make a seal between two flat surfaces, usually with a bolted joint. O-rings are round, ring-shaped pieces that must set in a groove to create a seal between two parts. While gaskets are most commonly circles, they are also manufactured in a variety of other shapes. Both gaskets and O-rings are made using flexible materials, but gaskets can also be made out of other rigid polymers and metals. The thickness of an O-ring can be customized to fit unique specifications, while gaskets may be layered with different coatings to work best for various applications.
Common Applications for Gaskets
- Electrical motors, power generators, and transformers
- Handheld communication devices
- Telecommunications equipment
- Aerospace and defense industry
- Transportation and automotive
- Medical devices
- Food and beverage industry
Common Applications for O-Rings
- Hydraulic seals
- Pipe joints
- Equipment with fluid seal points
- HVAC – Heating, Ventilation, and Air Conditioning
- Oil seals
- Fuel systems
- Food processing
- Pharmaceutical and medical industry
- Pulp and paper industry
Choosing the Best for Your Application
When deciding whether a gasket or O-ring is best for your application, consider the environment and function of the seal. When choosing the best seal, look for features such as shape, temperature, and pressure.
When a non-circular joint requires a good seal, an O-ring would be difficult to use because of its round shape. Gaskets can be customized to almost any shape, allowing them to work as a seal for a larger variety of applications.
The operating temperature of equipment will determine the best material to use for manufacturing the O-ring or gasket. While both can withstand a wide range of temperatures, gaskets are best for extreme temperature situations. However, O-rings perform better than gaskets in applications with extreme pressure.
Contact Us for Your Gaskets and O-Rings Needs
Mercer Gasket & Shim is a premium manufacturer of custom O-rings and gaskets in an array of materials and sizes to best suit our customers’ needs. Our team has over 80 years of experience in sealing solutions. We are committed to the highest standards with a target for 100% on-time delivery and a 0% defect rate, and strive to provide the fastest turnaround in the industry. To learn more about our cost-effective, durable sealing solutions contact us or request a quote today.
Everything from the size of the gasket to its ability to withstand degradation and damage plays a role in how well it can stop the escape of air, gas, water, or other fluids. Gaskets are placed between two flush surfaces that have a channel for fluid movement. Because the two surfaces might not be perfectly flush or straight, they’re going to have gaps that fluid can move through. Gaskets correct those gaps by being compressed between the two surfaces to effectively eliminate any leakage pathway.
Key Gasket Selection Factors — Gasket Materials, Types, and Uses
Some factors that buyers should consider as they purchase gaskets include:
- The amount of force the two surfaces will exude on the gasket
- The degree of surface unevenness (which dictates how thick the gasket should be)
- The fluids and any ambient contaminants
- The compressibility of the gasket material
If you know all the details of the application environment, you can choose gasket materials that withstand exposure to water, acidic or alkaline chemicals, oxidation, and more factors as needed. You can also pick gaskets with the right thickness, longevity, and malleability.
Selecting the right characteristics prevents gasket failure. These parts can fail if they’re exposed to chemicals that degrade the material or if the forces acting on the gasket are too great. This guide will focus on the six most important tips for choosing the perfect gasket for your needs:
1. Selecting the Right Gasket Material
Metal gaskets work best in extremely high-pressure applications. They create an initial line contact or contain the fluid through wedging once the two flush connection surfaces touch. Metal gaskets are also known as ring gaskets, and have either an ovular or octagonal cross-section. Octagonal cross sections provide a great deal of strength in the face of high pressure, such as the BX type that can handle 20,000 psi. Metal gaskets are commonly used in oil and gas industrial systems and secured with high-tension bolting.
Popular materials for metallic gaskets include:
- Low carbon steel
- Stainless steel
Non-metallic, or soft, gaskets, compress between two surfaces with little tension or pressure. This makes them ideal for applications where the fluid contents have low pressure levels and can’t force a leak pathway through the gasket. Soft gaskets are affordable, easy to find in different materials and specifications, and able to be used in low-temperature applications.
One common non-metallic material option, graphite, can also be used in high-temperature applications up to 500°C. These gaskets come in full face varieties, which cover the entire face of a connecting surface, and inside bolt circle gaskets, which cover a smaller ring of surface area on the face; one common application for full face gaskets is temporarily connecting utility lines.
Popular materials for non-metal gaskets include:
- Compressed Non-Asbestos Fiber (CNAF)
- Polytetrafluoroethylene (PTFE)
. Semi-Metallic/Composite Gaskets
Composite gaskets use both metal and non-metal materials, giving them the ability to provide a reliable seal in a variety of environments with different pressure and temperature factors. They are commonly used in male-female, raised face, and tongue-and-groove flanges. Because they contain less metal, they are often more affordable.
Three popular types of composite gaskets are:
Other Material Types
- Elastomeric: Elastomers are polymers with similar stretch and flexibility to rubber. Elastomeric gaskets are commonly used in utility applications alongside non-metallic gaskets. While these gaskets are elastic and can be deformed, they’re incompressible and can’t reduce in volume.
- Fibrous: Fibrous gaskets are another specialized type of non-metallic gasket. This category includes materials such as aramid, carbon, and glass fibers, cork, mica, and more. Each material offers very distinct properties.
2. Evaluating Fluid Temperature, Corrosive Properties, and Pressure
When gaskets aren’t properly aligned to the application environment’s temperature, materials, or pressure, they are at an increased risk of failure. Each gasket’s material is best suited for a specific range of fluid or ambient temperature; silicone, for example, has a much wider temperature range (-30°F to 350°F) than neoprene, which is only viable at temperatures between 30°F and 180°F. One of the first considerations when choosing a gasket material is to know the minimum and maximum operating temperatures of the fluid.
The chemical makeup of the contained fluids should also determine which material your gasket has. Factors such as pH level, oil or water content, oxidation qualities, and more can corrode or destroy different materials through regular or irregular exposure.
Gaskets also perform differently depending on the pressure levels. Non-metallic gaskets, which can provide a compressed seal at relatively low pressures, cannot provide adequate resistance if the contained fluid is too pressurized; the fluid can force a path through the gasket’s seal. Synthetic rubbers, for example, often have a cap of 60 psi for reliable performance. Metallic gaskets, on the other hand, are well matched to the extremely high pressures in oil and gas processing plants.
3. Choosing the Best Types of Gaskets
Once you know which material is best for the end application, you can select the right type, or structure, of the gasket. Some popular varieties include:
- Jacketed Gaskets: These have a soft non-metallic interior and a metallic coating. Jacketed gaskets are available in many varieties, such as single- or double-jackets (which have a coating on one or both sides), corrugated jackets, and more. The metallic coating gives non-metallic gaskets better resistance to damage.
- Solid Gaskets: These solid metal gaskets are extremely durable, but they require a lot of compression force to create a seal.
- Spiral Wound Gaskets: This gasket style has windings of metallic materials in soft, non-metallic gaskets, which combines both resistance to damage and flexibility. Piping and pumping systems often use spiral wound gaskets because of the reliable seal.
- Kammprofile Gaskets: These have a metal core surrounded by non-metal material on the top and bottom. It can create a tight seal along the gasket’s edge with extra reinforcement. They’re also easier to repair than comparable composite gaskets.
4. Talking to a Gasket Design Engineer
Working with a gasket design engineer is an excellent choice for creating a custom gasket for unique applications or for expert assistance in selecting the features your system needs. If you choose the wrong materials, design style, and type, you may degrade the life span of the surrounding system. Further, mass manufacturing a flawed gasket type can result in a failed project or excessive expenses. Talk to a gasket design engineer about your design specifications and environmental factors that should shape the final product.
5. Testing for Gasket Performance
There are multiple factors to test on a new gasket design to ensure the materials, specifications, and style create an adequate and cost-effective seal. Regulatory or standardizing organizations like Underwriters Laboratories set objective standards that industrial and commercial parts must meet to be safe for sale or use. The same organizations often establish what sort of tests or testing conditions are necessary to certify that a product is safe. These tests assess a gasket’s ability to withstand temperature, chemicals, pressure, and compression to retain a seal.
6. Choosing the Right Gasket Manufacturer
The right manufacturer is essential for ensuring the material success of your project. Look for manufacturers that have experience creating gaskets for the industries or markets you serve. It’s also important to choose a manufacturer with established design, testing, and inspection capabilities, so the final product is high quality and reliable.
Why Mercer Gasket & Shim?
At Mercer Gasket, we specialize in creating custom gaskets that meet our clients’ needs. Our team of technical specialists, design engineers, and industrial experts has created custom gaskets for the refining and power generation industries. We’re an ISO 9001:2015 certified company, and our standard is 100% on-time and 100% defect-free products.
Contact Us for Your Custom Gasket Needs!
Reach out to our experts today to discuss your project and request a quote. Also, download our Gasket Selection eBook for a more in-depth guide to creating the right gasket for your needs.
Rubber cork — a combination of milled cork grain and synthetic rubber — is a specifically formulated material that has been at the forefront of gasket technology since the 1970s. Also referred to as cork rubber, this material is available in many different sizes and variations, and is used in a broad range of applications and industries.
A combination of first grade granulated cork and rubber polymer such as natural rubber, synthetic rubber, silicone, nitrile, EPDM, or neoprene, rubber cork is held together with glycerin-glue applied under heat and pressure. The resulting formulation, about 70% cork grain and 30% rubber, is highly resilient and compressible with minimal sideways flow, making it an optimal sealing and chemical solution for modern gasket applications.
Advantages of Rubber Cork
The individual properties of rubber and cork combine to make a highly resilient formulation for volatile and rigorous environments. Rubber cork provides strong resistance to oil, solvent, and fuel, as well as moderate resistance to fungus, acid, and extreme weather conditions. With the ability to withstand sideways flow, rubber cork is also impact resistant, shock absorbing, and resistant to fluid penetration.
In addition to the physical and chemical resiliency of this material, other benefits of rubber cork include high compressibility and flexibility (characteristics of cork and rubber, respectively) and a wide range of fluid compatibility. It can be used with or without a pressure sensitive adhesive (PSA) backing, as it is already an anti-slip material. As such, rubber cork also provides acoustic insulation and reduces levels of transmitted vibration.
Typical Applications and Industries
Die cut rubber cork sheets are available in a range of sizes, densities, and thicknesses for a variety of applications such as gaskets, spacers, bumpers, protective pads, stripping, electrical transformers and switchgear, and more. The versatility of rubber cork allows it to fulfill specific requirements for many industries including automotive, aviation, railroad, shipping, agriculture, petroleum and electrical.
Why Mercer Gasket?
At Mercer Gasket & Shim, we offer full face, square, and rectangular rubber cork gaskets, made either in one-piece construction or dove-tailed for larger jobs. We maintain a large inventory of rubber cork products in our 50,000 square foot manufacturing facility, allowing for a rapid turnaround of parts for our customers.
For more information about the benefits of rubber cork gaskets and rubber gaskets or to learn more about how to incorporate this versatile material into your industrial application, contact Mercer Gasket today.
Reverse Engineering is the process of taking something without a blueprint, computer-aided design (CAD) file, or any other documentation, and being able to recreate it. Sometimes a customer will request a replicated part without any known design record on which to base the part; even having a sample part in hand won’t tell the whole story about how it was originally designed, created, and tested.
Mercer Gasket & Shim offers versatile reverse engineering solutions to virtually recreate any part with fast turnaround time. Our highly experienced team employs 2D reverse engineering technology that can be extrapolated into 3D models, design drawings, and QA documentation to create your new part without the aid of any previous design records.
From decades of experience, Mercer Gasket & Shim has identified three major hurdles and solutions to the reverse engineering process:
- Material identification and selection – Our customer service representatives are trained to review and measure your sample parts, as well as evaluate your application, in order to recommend the best and most cost-effective materials for the new part.
- Part measurement and documentation – Complex part measurement is time-consuming and error-prone. We employ Virtek LaserQC, an automated laser inspection system that is faster and more accurate than any human measurement or design documentation. LaserQC technology performs a day’s work in a matter of minutes.
- Accurate part fabrication – Once LaserQC has gathered digital specifications on your part, the information can be used to generate code for computer-aided manufacturing (CAM) operations to create the new part. Our technically trained staff will select the appropriate machine tools, such as laser or waterjet cutting, and generate the part.
Not only will Mercer Gasket & Shim evaluate your sample parts to reverse engineer new ones, we will also deliver to you the documentation recorded by Virtek LaserQC so that you’ll have the design records on file moving forward. We also offer additional services such as tool inspections, quality control, electronic archiving, design prototyping, and new tool fabrication.
At Mercer Gasket & Shim, we leverage reverse engineering expertise every day to find solutions and help our customers get the parts they need. To learn more about our reverse engineering solutions, we encourage you to download our eBook The Challenge with Reverse Engineering or contact us today.
Gaskets are vital for preventing the escape of fluids or air in several types of applications. Since gaskets are available in many different materials, sizes, and styles, selecting the right gasket can be a difficult and sometimes overwhelming experience.
Mercer Gasket has produced custom gaskets for over 80 years, so we know the criteria for choosing ideal products—that’s why we have created an eBook titled How to Select the Right Gasket. This free download is a guide to finding the gasket most suitable for your unique application.
There are many factors that need to be considered when making this choice, and this eBook has been specially crafted by our team of experts to explain the gasket selection process. This comprehensive guide will discuss topics that include:
- Selection Factors and Properties
- Gasket Materials (Elastometric and Fibrous)
- Gasket Construction (Soft, Non-Metallic, Semi-Metallic, Metallic)
- Testing (As per various industry standards)
With an in-depth understanding of the variables pertaining to gaskets, we aim to prevent you from experiencing gasket failure and potential downtime or equipment failure. Matching the properties of the gasket to the application ensures optimal performance.
As a leader in the manufacturing of gaskets for several industrial applications, Mercer is an authority on providing our customers with the materials and knowledge they need to make informed choices. Download your free copy of How to Select the Right Gasket on our website, or by clicking the button below and filling out a short form.
We can also provide other resources, including material guides, metric/decimal equivalent charts, and chemical resistance chart that can be found in our Resource Library. Please contact us if you need further assistance choosing ideal gaskets for your application—our customer service representatives are always available to help.
The location of a gasket is of utmost importance, especially if it is going to be exposed to the elements. For this reason it’s imperative to choose top quality weather resistant materials to enhance the longevity and performance of outdoor gaskets. There are a number of important factors to think about in regard to weather resistance including sunlight, temperature, ozone, and inclement weather conditions (rain, hail, sleet, snow, etc.).
Weather’s Effect on Gasket Performance
Many outdoor gaskets experience direct sunlight. This can increase internal temperatures to more than 140°F. In addition, heat cycling can accelerate compression set in many gasket materials.
On the opposite end of the spectrum, gaskets in many climates experience freezing temperatures during winter. Frozen gaskets are highly susceptible to cracking, and problems can intensify when the temperatures rise above freezing. As snow and ice melt, gaskets that stiffened due to cold temperatures are more apt to leak.
Additionally, gaskets often require ozone and ultraviolet light (UV) resistance. Ozone not only occurs in nature, but also can be generated by certain outdoor enclosures that house electrical components. UV exposure can also be detrimental to a gasket’s life and integrity.
UV and ozone resistant materials should always be considered for gaskets that will be outdoors or near electrical enclosures. Finally, whenever gaskets are compressed and then re-compressed by any type of weather conditions, it’s important to choose gaskets that have the ability to be rebound.
Materials That Stand Up to the Elements
The following are a few examples of commonly used materials that help minimize the impact of harsh weather conditions.
- Fluoroelastomer (Viton®) –This is a fluorocarbon-based synthetic rubber well-known for its excellent performance and resistance to chemicals. It is also highly resistant to many extreme environmental conditions. Fluoroelastomer can handle high temperatures, ozone, and oxygen, as well as fuels, mineral oil, and synthetic hydraulic fluids. It can operate in maximum temperatures from 400°F during continuous service and up to 500°F in intermittent service.
- Polyurethane – This compound features excellent abrasion resistance and tensile strength compared to other elastomers, and these qualities translate well into excellent performance in all weather conditions. It also features good resistance to ozone and operates in temperatures as low as -22°F and as high as 230°F.
- Ethylene Propylene Diene Monomer (EPDM) Rubber – EPDM rubber is compatible with a wide variety of materials and exhibits outstanding weather resistance. This synthetic rubber can resist the deteriorative effects of ozone, oxygen, heat, and weather, along with many chemicals, oils, and acids. EPDM has a wide range of serviceable temperatures, from -40°F to +250°F, and intermittent to +275°F. It also exhibits excellent resistance to steam and polar substances.
- Silicone – Silicone is an extremely versatile material. It features excellent elastomeric properties at both low and high temperatures. Silicone is highly resistant to oxygen, ozone, UV light, aging, weather, and extreme temperatures. It works in temperatures that range from -67°F to +400°F, and intermittent to +450°F.
There are numerous options for outdoor gasket sealing. The materials listed above have a number of advantages and disadvantages when it comes to cost and resistance to specific weather conditions.
Talk to a Professional
At Mercer Gasket and Shim, our team of experts is available for consultation 24 hours a day if you need assistance choosing the right gasket material for your application. Our ISO 9001:2008 certified facility stocks a broad range of gaskets and gasket materials, able to suit any weather-related application. Contact us today to learn the many advantages of making Mercer your gasket and sealing product source.
Read more about the materials used by Mercer Gasket in our full Materials Guide, available for download here: