Category Archive: Uncategorized

Why Should You Choose Flex-Tex Expanded PTFE Instead of PTFE?

Expanded polytetrafluoroethylene (ePTFE) is a type of PTFE that offers flexibility, permeability, chemical resistance, and linear strength. It has widespread applications, in everything from the medical, pharmaceutical, and dental industries to aerospace and telecommunications. While it shares some properties with conventional PTFE, its unique structure makes ePTFE a preferred material for various applications. In this blog, we will explore ePTFE, its primary properties, and the applications that depend on the material.


Common for tubing, cords, and sealing tapes, Flex-Tex — another name for ePTFE — offers greater flexibility compared to conventional PTFE. The synthetic fluoropolymer material has a soft, spongy feel reminiscent of a marshmallow. Its pliability is a product of its microporous structure, which consists of a high strength fibril matrix.

The ePTFE production process creates this heavily connected fibril matrix as manufacturers expand the material in controlled environments. Manufacturers can adjust the material’s flexibility to meet the needs of a specific client or application by varying the production process. Gaskets, seals, and related applications that benefit from increased flexibility utilize conformable ePTFE.


ePTFE is also an excellent material for applications requiring high permeability. Its microporous nature makes it permeable to air, which PTFE is not, as well as other gases and water vapor. Despite this, ePTFE still maintains its resistance to particulates and liquids. Flex-Tex’s permeability makes it ideal for applications in the following:

  • Ventilation
  • Filtration
  • Making waterproof and breathable fabrics

Like with ePTFE’s flexibility, the production process allows manufacturers to create Flex-Tex with the desired permeability for a specific application.

Chemical Resistance and High Linear Strength

As a fully fluorinated polymer like standard PTFE, Flex-Tex provides excellent resistance to various chemicals. It’s also chemically inert and non-reactive when applications expose it to most other chemicals and solvents. The material can maintain its integrity in the presence of concentrated nitric or sulfuric acids, as well as other corrosive substances.

As a fully fluorinated polymer like standard PTFE, Flex-Tex provides excellent resistance to various chemicals. It’s also chemically inert and non-reactive when applications expose it to most other chemicals and solvents. The material can maintain its integrity in the presence of concentrated nitric or sulfuric acids, as well as other corrosive substances.

ePTFE Services From Master Packing and Rubber Company

Flex-Tex or ePTFE is expanded under controlled conditions to deliver unique material properties that conventional PTFE cannot. That said, it’s the requirements of your individual application that determine whether standard PTFE or ePTFE would be your best option. When selecting a material for your project, speak with an engineer or materials specialist first to help you determine the ideal choice.

At Master Packing and Rubber Company (MPRC), we’ve been delivering innovative, USA-made sealing solutions for clients since 1982. Among our product line of custom cut gaskets and seals, mechanical packing solutions, chemicals, and materials, we offer versatile, high-performance Flex-Tex expanded PTFE as a reliable joint sealant, ribbon, pipe tape, and valve stem packing option. With an adhesive backing, Flex-Tex can help you handle your maintenance and emergency needs in industrial equipment.

This FDA-compliant material of 100% pure PTFE is compatible with nearly any surface material, producing an exceptionally tight seal with simple application. As a form-in-place gasket, it’s rated for temperatures ranging between -350°F and 550°F as well as a pH of 0 to 14, and resists cold flow and creep. This long-lasting sealing solution also provides an unlimited shelf life, not experiencing deterioration over time.

At MPRC, we strive to provide real solutions to diverse problems and environments. Contact us to find out if Flex-Tex is the ideal choice for your application, or request a quote today to get started.

What Are O-Rings? All You Need to Know

What is an O-ring, and what purposes do various O-rings serve? While an O-ring’s basic function is relatively simple, there are several important considerations to make when choosing the right one for your application to ensure your O-ring can withstand high pressures, temperatures, and other operating conditions. Read on to learn more about O-rings, what various industries use them, and how to select the right O-ring for your needs.

What Are O-Rings?

O-rings, also known as rubber rings or toric joints, are ring-shaped seals possessing a circular cross-section to resemble their namesake letter O. They’re primarily made of a rubber elastomeric material and provide an affordable and reliable means of sealing hydraulic, pneumatic, and related machinery components. It should also be understood that in addition to elastomeric materials such as the standards as Nitrile, Neoprene, EPDM, Silicone, and others, that O-rings are also made from metals, thermoplastics, fluoroelastomers (FKMs) like Viton™, all application-specific materials for optimal performance. Popular for their easy manufacturability and fit, they secure to mating surfaces and prevent pressurized liquids or gases from escaping hoses, piping, and other such system passageways.

Click to Expand

What Are O-Rings Used For

What Are O-Rings Used For?

O-rings have applications across diverse industries to fulfill varied sealing needs.


O-rings are essential to the transportation sector, supporting modes of transport ranging from cars and trucks to railroads, marine boats, and aircraft. The best elastomer for a given transportation application depends on its intended exposure to vibration, temperature extremes, chemicals, and harsh environmental conditions. These O-rings will also have to comply with emission and biofuel regulations, which is why manufacturers continue to innovate to create custom O-rings that meet Tier 1 and OEM standards.

Oil, Gas, & Industrial

Oil and gas refineries use countless valves, fittings, pumps, storage tanks, and other components that require durable seals. O-rings for industrial use must stand up to high pressures and temperatures, as well as corrosive chemicals. Such applications benefit from O-rings composed of peroxide and triazine-cured perfluoroelastomers and other such specialized compounds.


O-ring uses in the electronics industry include protecting sensitive electronic components from contaminants like dust. To fulfill this sector’s need for particulate-free O-rings for applications like semiconductor processing, manufacturers can produce them in clean environments from an array of material options.


The medical sector depends on O-rings for connectors, filtration systems, pumps, and syringes. To ensure product safety for patients and healthcare workers, manufacturers of O-rings for medical equipment must construct them from specialized, medical-grade materials and in sterile clean room conditions.

Food & Beverage

Equipment for food and beverage processing and dispensing, as well as water filtration applications, all require effective, FDA-compliant sealing solutions. Specialized O-rings constructed in accordance with food safety and sanitation standards are available to meet NSF-61 and 3A sanitary requirements.

Considerations for Choosing an O-Ring

While there are numerous types of O-rings available, the right option is the one that precisely matches the intended application. When comparing different O-ring materials, you can make the proper selection by evaluating multiple factors.


Choosing the right material is critical to ensuring an O-ring can handle your application’s:

  • Pressure limits
  • Ambient and operating temperatures
  • Exposure to chemicals, acids and bases, and other sources of corrosion
  • Likelihood of experiencing vibration
  • Industry standards (e.g., sanitation, food safety, etc.)

Pressure Rating

O-rings provide leak protection within pressurized systems, and each comes with its own pressure rating. It’s important to have a thorough understanding of the maximum pressure utilized in your system and select an O-ring with a PSI rating that exceeds that maximum by a safe margin.


In designing for O-ring use, whether standard AS 568A sizes will be used or a custom size, it is critical that not only compatibility to the media being sealed is considered along with temperature and pressure, but also stretch and squeeze of the O-ring for the application, whether it is to be used as a static seal or to be used as a dynamic seal, in which case friction must also be considered.

Durometer Hardness

O-rings must also be the right hardness for their intended application so as not to experience deformation. Manufacturers can verify an elastomer material’s hardness using a Shore durometer. Typical O-rings usually have durometer ratings that normally fall between 40 and 90, meaning that their material is on the softer or harder side, respectively.

O-Ring Solutions From MPRC

Choosing the right seal for your application depends entirely on the use conditions involved. At Master Packing and Rubber Company (MPRC), we specialize in rubber elastomer and related seal technologies to withstand varied environmental exposures and operating conditions. Our cut gaskets and seals support peak performance in your systems, designed for optimal leak protection. O-rings from MPRC are available in a range of material and design options so that we can provide the product versatility that clients in diverse industries require to find ideal sealing solutions. While we produce a variety of customer specific designs, we also provide standard AS 568A sizes and stock in several elastomeric materials.

Contact us to learn more about the various O-rings we offer, or request a quote today.

Exhaust Gasket Material: Types and Applications

Click to Expand

Exhaust Gasket Material: Types and Applications

Exhaust systems are exposed to extreme levels of heat, which means their gaskets must have the properties to withstand this and other harsh conditions. Learn about the characteristics to look for in exhaust gasket materials so that you can select the right types of gaskets for your exhaust system.

Ideal Characteristics of Exhaust Gasket Materials

The following are some of the specific characteristics to look for in exhaust gasket material types.

Heat-Tolerant Filler Material

The facing/filler material of the exhaust gasket must be able to handle exposure to high temperatures without any compromise in its structural integrity. Otherwise, the seal can experience premature wear and failure.

Metal Reinforcement

Gaskets with metal reinforcements will benefit from increased durability, strength, and holding power throughout their service life.

Low Creep Relaxation

Graphite filler materials give the gasket low creep relaxation. Low creep relaxation means that the gasket material won’t experience much loss in thickness over time or under exposure to extreme heat. As a result, the gasket will maintain reliable flange loading that keeps the seal intact.

Abrasion Resistance

If your exhaust system contains joints with high thermal motion—including joints made of two or more dissimilar metals with varying contraction and expansion rates under heat—you may benefit from a clad-style exhaust gasket material to resist abrasion.

Exhaust Gasket Material Types

Based on the characteristics required of your gasket material, you may select one of the following gasket material types:

  • Composite graphite — Some gaskets may use composite graphite for its superior performance and lighter weight. Many of our composite graphite exhaust gaskets have a Kammprofile design, especially for use in the marine and rail sectors.
  • Multi-layer steel — These gasket materials comprise multiple sheets of either carbon or spring steel with the sealing material between them. Our rail and marine multi-layer exhaust gaskets are double-jacketed.
  • Multi-layer steel with MOS coating — This multi-layer steel material has a dry film lubricant coating made of molybdenum disulfide (MOS) to help reduce wear.
  • Ceramic coating — A gasket with a ceramic coating will withstand road grime, water stains, and other types of substances.
  • Sandwich type — These gaskets include two thin layers of aluminum, copper, steel, or another type of metal with a center layer of graphite.

Exhaust Gasket Material Applications

Our exhaust flange gasket materials are compatible with a wide range of exhaust systems from major manufacturers:

  • Caterpillar: C7, C9, C10, C12, C13, C15, C27, C32, and G3500 engines
  • Cummins: QSK60, IX, ISB, K38, ISX12, and QSB3.3 engines
  • Detroit Diesel: S60 and DD15 engines
  • Mack: E7 engines
  • MTU: Series 4000, Series 396, and Series 2000 engines
  • Navistar: DT466 engines
  • Volvo: D12 engines
  • EMD: 567, 645, and 710 engines
  • Wabtec: GE 7FDL engines

Find the Best Exhaust Gasket Materials at MPRC

It’s important to find the right exhaust gasket material for your application based on the types of conditions your exhaust system experiences. At Master Packing and Rubber Company, we provide our customers with innovatively designed and manufactured gasket exhaust materials that meet the requirements of various engines.

For more information about our products and capabilities, request a quote today.

Cut Gaskets vs. Molded Gaskets: What Is the Difference?

Click to Expand

Cut Gaskets vs. Molded Gaskets: What Is the Difference?

Gaskets fill the gap between the surfaces of two parts, joining them and creating an effective seal that prevents leakage. Manufacturers have multiple methods for producing various types of high-quality gaskets, depending upon the material selection, available equipment, and application requirements.
Two common options are cut gaskets, which manufacturers cut from sheets of raw material, and molded gaskets, which are the product of one of several molding processes. Learn more about the unique advantages and proper applications of each type to help you choose the right option to fulfill your gasket needs.

Cut Gaskets Explained

From a sheet of material, CNC machinery cuts large volumes of components at high speeds, producing identical gaskets. They sit between two surfaces and create a tight seal through compressive force, filling any space caused by unevenness, gaps, or imperfections on those surfaces to make up for any design flaws. With common mechanical and plumbing applications, they’re useful for:

  • Automobiles
  • Bearings
  • Controls
  • Plumbing systems
  • Pumps
  • Valves

Advantages of Using Cut Gaskets

Some of the key advantages of CNC-cut gaskets include:

  • Production speed. As you won’t need to first create a custom die to generate your gaskets with die-less gasket cutting, you can achieve quality gaskets in a matter of minutes or hours rather than the process taking days or even weeks.
  • Cost-effectiveness. CNC-cut gaskets don’t require expensive tooling or molds, just development costs for the computer-aided design (CAD) file to guide the cutting process. This process makes cut gaskets more affordable to produce than using alternate techniques.
  • Shape customization capabilities. When you need gaskets in specific sizes or unique profiles, CNC-cut gaskets offer versatility in their customization options.
  • Resistance abilities. Equipment systems commonly utilize hot fluids, meaning gaskets must withstand high temperatures and pressures. Cut gaskets come in an array of materials, allowing you to choose one with the right pressure and heat resistance for a long-lasting seal.

Molded Gaskets Explained

Molded gaskets offer more complex and versatile designs. First, manufacturers build a precision mold with a cavity in the shape of the desired gasket. Then they fill the cavity with a plastic, rubber, or other uncured elastomer substrate where, through heat and pressure, the material sets and cures, retaining the mold’s shape.
Three common techniques for producing molded gaskets are:

  • Injection molding. The fastest of the molding processes, injection molding produces highly consistent gaskets that minimize or eliminate the need for secondary finishing or trim work due to their optimal surface finish without flashing.
  • Compression molding. Manufacturers turn to compression molding to generate large-sized molded gaskets. It’s a cost-effective method with low mold and per-part costs, and it produces little unreusable waste.
  • Transfer molding. This process is relatively fast and, compared to compression molding, transfer molding offers enhanced uniformity in gaskets. It’s well-suited to manufacturing molded rubber-to-metal components.

Advantages of Using Molded Gaskets

While there are tooling costs that accompany the molding process, molded gaskets offer a range of benefits, including:

  • Enhanced design options. Using custom molds, you can generate three-dimensional gaskets, integrate additional parts into your mold’s design, create parts with varying cross-sections, incorporate engraving, and more. 
  • Dimensional accuracy. Molded gaskets offer tighter tolerances than cut gaskets, particularly where thickness is concerned. They create a secure bond between surfaces while enabling joint flexibility.
  • Improved leakage protection. Molded gaskets don’t have splices, creating fewer opportunities for leakage.
  • Minimal waste. Molding generates little material waste, which equates to the added benefit of per-part cost reductions.

Gaskets We Offer

At MPRC, we offer a wide range of gaskets and manufacturing options to suit your needs, including:

  • Molded gaskets. Through injection, compression, or transfer molding, molded gaskets form through heat and pressure, offering design freedom, high performance, and close tolerances.
  • Lathe-cut gaskets. A CNC lathe turns a tube of material on a mandrel against a tool to cut material away and achieve completed, structurally stable gaskets in the desired shape.
  • Extruded gaskets. Elastomeric polymers like uncured rubber are forced through an extrusion die before being cut into the appropriate dimensions, taking the shape —  be it simple or complex — of the die.
  • Spliced gaskets. These gaskets start as extruded of material cut into specific lengths, after which the ends bond together through heat and/or adhesives for strong joints.
  • Metal gaskets. Formed or cut from large sheets of metal or alloys, these highly durable gaskets create a tight seal with good pressure and chemical resistance capabilities.
  • Die-cut gaskets. Using a premade die and any of several die-cutting processes, you can cut gaskets with tight tolerances out of a sheet of material.

Find the Gaskets You Need With MPRC

Master Packing and Rubber Company (MPRC) is a leading provider of seals, gaskets, and mechanical packing materials, with USA-made products for clients across the globe. Contact us today to learn more about what type of gasket is the right fit for your next project or to start your order.

How working with MPRC, (an ISO-9001 and AAR M-1003 Certified Manufacturer,) benefits you- our customer.

Here’s a great article highlighting the reasons to work with a manufacturer who is ISO Certified.  Master Packing & Rubber Company (MPRC) is not only ISO-9001 Certified, but AAR M-1003 Certified as well.  What does this mean for you, the customer?  Assurance.  You can rest assured that as a gasket manufacturer, MPRC will work to continuously improve upon our processes, attacking any problems that may arise to ensure they do not happen again.  Ultimately, the goal is to make our organization better, more accountable, and provide the best possible service to our customers.


Thinking “outside the box” to provide innovative sealing solutions: The fully-molded “Ladder Gasket” from MPRC.

                             The “Ladder Gasket” from MPRC

Master Packing & Rubber Company (MPRC) takes great pride in “thinking outside the box” to do whatever it takes to assist our customers, and we never shy away from challenging or problem applications that many suppliers turn down.

One example of a solution we provided our customer is a fully-molded “Ladder gasket,” which goes inside a large rotating drum.  The previous OEM version was not only failing after limited use, but the lead time to acquire a new seal was excessive.  This made the overall replacement cost and down-time while waiting for new parts a losing effort.

MPRC was able to fully-mold this gasket in house thanks to our customer sending us the actual drum that the gasket fits in to ensure a precision fit, resulting in proper sealing.  In addition, MPRC determined the best material needed for the application based on temperature, pressure, rotation, and media the material seals against.  The result:  an improved seal that exceeds OEM standards, improves service life, and provides a cost savings to the customer with drastically improved lead times.

The MPRC “Ladder Gasket” is just one example of the many custom molded seals that MPRC offers our customers.  Contact us at 800-397-3429 to see how we can assist you with your application!

Industrial News: Reflecting on a great 2022 FEW Show

A look back at the 2022 Fuel Ethanol Workshop (FEW) in Minneapolis, MN

MPRC recently attended the Fuel Ethanol Workshop (FEW) in Minneapolis, MN.  As a leader in innovative seal technology, the goal of exhibiting at this year’s show was for MPRC to continue to increase awareness of our current presence in the Industrial and Ethanol Industry, and showcase how we serve both the producers and equipment manufacturers of these industries.

This was the first time that MPRC exhibited at this particular event, and we are thrilled with the response and turnout we had at our booth.  We take great pride in working with the individuals in this unique, hard-working industry, and are proud to assist them and help keep them running.

FUN FACTS:  There are nearly 200 Ethanol Plants (195 to be exact at this time) across the United States. MPRC proudly serves well over half of the Top 10 largest Ethanol facilities with Industrial and fluid sealing components.


P.S.:  To show his loyalty and appreciation for this Industry, Dave brought home a Trackmobile to drive back and forth to work!  (We’re kidding of course, but it’s a fun picture! :)

MPRC Team Member Spotlight: Patrick (Pat) Silvey- VP of Technical Service & Sales

Patrick (Pat) Silvey

VP of Technical Service & Sales

Joined Master Packing, 2017

Not only is Pat a valuable asset to us here at MPRC in his role as VP of Technical Service and Sales at MPRC, but he can hold the beat down and lay down some serious notes on the skins too. Pat’s been a drummer for years, and best describes himself as “A musician that’s dedicated all percussive efforts to guiding many secondary instrumentalists like guitar and bass players to sound better. Maybe a singer or two — although I have great respect for piano players, they are at the top of the heap of secondary instrumentalists. Needless to say, drums rule!”

Pat started his diesel engine career in the 1970s working within the rail and marine industry. Much of his mechanical knowledge has been gained through hands-on experiences that have enabled him to understand the mechanical complexities that port engineers and chief mechanical officers face on a daily basis.

Through the years, Pat has done an incredible job assisting customers in acquiring parts best suited for their applications. MPRC can assure you that if you’ve called us for assistance in obtaining a correct part number or need reassurance that what you are purchasing is the correct part for the engine application, Pat has most certainly had something to do with providing that service.

Pat is an absolute joy to work with, and we joke internally that he’s our “resident mechanic.” And although the truth is he wasn’t one “officially,” you’d never know otherwise. Pat set himself apart from the pack by paying close attention to the real field and service mechanics that he assisted in engine rebuilding and problem-solving. This close attention to detail has translated beautifully into a very technical sales role that is tremendously valuable to the team at MPRC and how we serve our customers as fluid sealing specialists.






MPRC’s Bio-Fuel “science project!”

MPRC Bio-Fuel Test

To cover our recent test and findings, we need to briefly identify what a Bio-Fuel is:

Bio-Fuels- unlike other renewable energy sources, come from biomass such as plant or animal waste.  A Bio-Fuel comes from the conversion of this waste into a liquid fuel, used to meet transportation fuel needs. There are two common types of Bio-Fuels:  Ethanol and Bio-Diesel.

Ethanol: A Bio-fuel as it is normally made from corn, although sugar cane is also used, mostly in South America.  Blended with gasoline, it increases octane and cuts down carbon monoxide and other smog-causing emissions.

Bio-Diesel: Combined with alcohol, it is a liquid fuel produced from renewable sources such as new and used vegetable oils and animal fats or cooking grease, and is a cleaner-burning replacement for petroleum-based diesel fuel.  It’s also non-toxic and biodegradable, and is a cleaner-burning fuel than diesel, eliminating much of the particulate matter that goes out of the exhaust including hydrocarbons, carbon monoxide, and others. Bio-fuels also give a cleaner burn over regular gas, although they do emit about the same amount of CO2 as gas.

Simply put- you can’t use just any O-ring or rubber material when it comes to Bio-Fuels.  For example, the aggressive, contaminated Bio-fuel attacks hydrocarbon rubbers such as nitrile rubber, widely used in fuel handling hose, gaskets, and seals. MPRC recommends selecting a Viton Fluoro-Hydrocarbon Elastomer (FKM) for Bio-Fuel service. Of all the testing of various Viton compounds in Bio-Fuels, results have shown that Viton has excellent compatibility with Bio-Diesel (both fresh and contaminated), and has a high resistance to permeation and chemical attack by alcohol, pure ethanol, and blends of ethanol with hydrocarbon fuel.

Just the other day, the team at MPRC was discussing Bio-Fuels and the effect that Bio-Fuels have on Elastomers. Then I remembered something really neat that we did years ago, that I hoped was still around- somewhere. Much to my surprise, it was!

In 2008, we started a test on some O-rings and grommets designed and formulated in our yellow Viton “B” compound. We had acquired some Bio-Diesel from a local company that is unfortunately no longer in business, but they used to offer classes on how to produce Bio-Diesel and even sold equipment to do so.

We decided to place two of our head gasket grommets and a few O-rings into the Bio-Diesel and let it sit- and that we did. I had for the most part forgotten about this, but our discussion earlier this week made me remember.  Finally, after sitting in a jar for that long, it was time to remove the items and see how they measured up against the Bio-Diesel.

I don’t know a whole lot of products these days that can say they’ve held up to something like a Bio-Diesel for 14 years- but ours did!

Here are our specific findings:

After removing each item from the Bio-Diesel jar, we carefully inspected and checked the dimensional tolerances.  MPRC carefully checked the inner and outer diameter of each item in addition to the overall hardness of each material. To our surprise, ALL of the items remained well within the proper dimensional tolerance/spec.   Not only that, but on a few of the items, you can still see the “MPRC” that is raised and embossed into the molded ring very clearly and without any distortion. NOTE: There is a small chunk taken out of the more faded yellow grommet. This is not due to anything relating to Bio-Diesel.  MPRC removed a small piece of the grommet to send for testing and lab analysis on the original compound.

Call us hoarders of our precious little Bio-Diesel container, but we like to think of ourselves as brilliant scientists who have made an incredible breakthrough. We’re kidding, of course. We think we do a pretty good job of being fluid sealing specialists, however, and doing fun little science experiments like this to see how our products hold up is a lot of fun. Call us today and see how we can assist you with your fluid sealing needs!


**References: “Biofuel Basics”– Office of Energy Efficiency & Renewable Energy, Bioenergy Technologies Office**