Gaskets & Seals

How Do You Recognize a Quality Gasket

Gaskets themselves are inexpensive but often expensive to replace. A high-quality gasket fits well and prevents leaks or ingress of contaminants until the next scheduled maintenance, and preferably longer. An inferior product could leak prematurely, forcing an expensive unplanned shutdown That’s why it pays to buy good custom-cut gaskets, but how do you differentiate between one that’s high quality and one that isn’t?

Was the Gasket Protected During Shipping?

Look at the packaging the gasket came in. If that’s bent, folded or compressed there’s a good chance the gasket material has taken some kind of compression set. Does it look like it was exposed to sunlight? UV light will shorten the life of an SBR or nitrile gasket, although neoprene and silicone gaskets are less sensitive.


Did the manufacturer take the time to clean both sides of debris from the cutting process? Small particles stuck between the flanges could create a leak path.

Gasket Material

Look to see that the gasket manufacturer has used the material you expected, (if that was something you specified,) and not a cheaper lookalike.

Gasket Edge Quality

This is determined by the cutting process used and the condition of the tooling and equipment. While the OD surface of a flange gasket is primarily just aesthetics, (unless it has to fit in a groove or channel,) a shoddy appearance reflects poorly on the installer.

Internal edges are more functionally important. Check for strings of material not quite cut through as these could get into the material flow. Likewise any cutouts, (like a bitemark,) can create a cavity that causes turbulence, creates noise and reduces flow velocity.


Check for dimensional accuracy before stripping down the joint or opening the flange! A quality gasket will be cut to exactly the sizes you asked, (within the limits of what the cutting process can do.)

Cutting Corners Never Pays

A poor quality gasket might cost a little less, but if the joint leaks and needs repair it can be a costly decision. That’s why you should know how to recognize a quality gasket.

Contact Hennig Gasket & Seals when you require high-quality custom cut gaskets.

Hennig Gasket & Seals – Part of Chicago

Hennig Gasket has been in business close to a century, and there’s still a Hennig at the helm. The business was started by Otto Hennig in 1920 before passing to James Hennig. He ran it for forty years until his retirement in 1987, and now it’s run by third and fourth generations of the family.

A lot has changed in that time. When Otto Hennig started the business the automobile was in its ascendancy, electricity was spreading across the country, and demand for gaskets for heating systems and manufacturing operations was growing. Of course, Chicago endured a few challenges in that period, but who knows, maybe cork or fiber gaskets made by Hennig found their way in to some of the bootlegger’s stills!

Some things haven’t changed though. We still make traditional cork and fiber gaskets, die cutting them from sheet, or if we don’t have the tooling, using an oscillating knife or even just hand cutting. If you’re maintaining or restoring aging equipment that used gaskets like these we can supply replicas of the originals. Alternatively, you may prefer upgrading to one of the many modern gasket materials that manufacturers have developed.

One example of material changes is the rise and fall of asbestos gaskets. Once essential in high temperature applications like boilers, (and perhaps stills,) these have been replaced by a range of non-asbestos gasket materials like Garlock BLUE GARD®. (This incorporates aramid fibers in a nitrile, neoprene or SBR binder.)

Neoprene and SBR gasket materials have themselves been around a long time, (just like Hennig Gasket & Seals!) but today there many newer alternatives. Elastomers like EPDM and FKM are proving valuable in many applications, especially for sealing against corrosive and high temperature fluids.

The best way of learning about gasket material properties is by speaking with an expert. At Hennig we’ve accumulated a wealth of knowledge and experience. And if you’re in the Lower West Side neighborhood of Chicago, call in. Just look for the brick mill-style building at 2350 West Cullerton.

Custom Gasket Cutting

One of the challenges with replacing gaskets is that you don’t always know what kind of replacement is needed until you get the joint apart. If you’re lucky it takes a standard gasket that you can collect or have shipped out. If you’re unlucky though you’ll need a fabricator who provides custom gasket cutting — FAST.

The Cost of Downtime

When a gasket starts failing prompt replacement is essential: product is being lost, yields are falling, and profits suffering. Worse still, you might be risking both ground contamination and fugitive emissions from pipeline leaks, which could lead to legal action and fines.

Unfortunately, gaskets can’t be replaced without taking joints apart. That means shutting down production so that pipes are cool and empty. Once the new gasket is in place, start-up may take several hours. Lost production means lost sales, and that money may never be recovered.

Gaskets and Inventory Costs

Few maintenance departments have the luxury of keeping in stock every gasket that might ever be needed. Even if there was enough space and Accounting would tolerate the costs, the material ages and eventually becomes unusable.

Just-in-Time Delivery

Many maintenance operations have adopted a different approach. Instead of carrying a large gasket inventory, they’ve aligned themselves with custom gasket suppliers capable of rapid delivery.

Configuring a business to cut and deliver custom gaskets in just hours takes a significant commitment of time and money. A large inventory of gasket material is essential, as are flexible cutting processes that don’t demand long lead-time tooling.

With an extensive range of material on-hand, plus computer-controlled cutting machines, Hennig is positioned to provide the fastest possible turnaround. To save time, new gaskets are often reverse-engineered from the one that’s been removed, and it’s not uncommon to work from photocopies of gaskets and even hand-drawn sketches.

Gaskets Aren’t Expensive, Downtime Is

When you need a gasket in a hurry, think of Hennig. A massive inventory of gasket material, combined with flexible cutting/manufacturing processes means we can produce a custom gasket in just hours. That means less downtime, which goes straight to your bottom line. Contact us today for fast and accurate custom cut parts.


Custom Gasket Cutting

At Hennig we provide custom gasket cutting services. If the material is in stock we can usually get a new gasket shipped out the day it was ordered.

The key to this rapid turnaround is cutting process flexibility. With flash, die and water jet cutting equipment on-site we’re able to select the fastest and most cost-effective process for your order. Whether you need one gasket or one thousand, prototype or production runs, we have a process that works.

Accuracy and appearance are important considerations too. A gasket that fits poorly or has rough, uneven edges leaves a negative impression of the equipment it’s installed on, and probably won’t last as long. Our cutting processes provide a range of finishes to suit your needs.

Flash Cutting Services

Flash cutting uses a  gantry machine that moves an oscillating knife over sheet material up to 60” x120”. The knife cuts straight edges or curves in material up to 1/2” thick, leaving smooth vertical edges. Knife motion is computer-controlled with the cutting path programmed directly from a CAD file, and nesting software maximizes material utilization.

Die Cutting Services

A die cutter uses a metal blade shaped to the profile of the gasket and embedded into a wood block or panel. With die cutting it’s possible to cut to a precise depth, which is useful when you don’t want to separate individual pieces from the sheet. Technically described as “kiss-cutting,” this allows gaskets to be kept together on a sheet or roll and peeled off as needed. It’s a good method for producing gasket kits.

Unless a die already exists, die cutting will incur a tooling charge along with some lead time. However, it is a fast and repeatable process, which makes it economical for quantity orders. We can die cut gaskets as large as 36” x 72” from sheet material. Cut edges are smooth although thicker material may show a small degree of curvature.

Water Jet Cutting Services

Also a gantry-style machine, water jet cutting cuts with a jet of fast-moving water just 0.010” wide. The thin jet means minimal material waste, and tolerances as tight as +/-0.007” can be maintained. Depending on the material, it’s possible to cut up to 6” thicknesses and the largest size we can produce is 72” x 96”.

Like flash cutting, a water jet is programmed directly from a CAD file of the gasket required. One strength of water jet is that there’s no material deformation during the cut, which improves edge appearance.

Ask about custom gaskets

Many sealing applications need a custom gasket. At Hennig we have a range of equipment for cutting sheet gasket material and this lets us provide a rapid turnaround. Many custom gaskets ship the day they were ordered.

Using Die Cut Gaskets for Electrical Enclosures

Electrical and electronic equipment should always go in an enclosure designed to protect it from water and dust. However, the enclosure is only as good as the gasket that seals it.

An electrical enclosure gasket needs to accommodate irregularities in the surfaces of both door and enclosure, and continue to seal after repeated opening and closing. It should also resist varying degrees of external pressure, depending the standard applicable.

Outdoors, the threat usually comes from rain, which may be wind-blown but seldom impacts the enclosure with significant force. In industrial situations, especially in the food, medical and pharma sectors, enclosures are often expected to resist high pressure washdowns.

Standards for ‘ingress protection’ are promulgated by several organizations, notably the International Electrotechnical Commission (IEC,) NEMA and UL. The IEC 60529 standard defines the IP levels that many engineers know. (IP65, 66 and so on.) NEMA standards are seen as more demanding in terms of not allowing water penetration but only address design intent. Only UL insists on third party testing to verify compliance.

Three types of gasket are used in enclosures:

  • strip
  • ‘foam-in-place’ (FIP)
  • die-cut

As the name suggests, a strip gasket is cut from sealing material and applied in lengths to the enclosure door. Inevitably that leaves gaps. Dust may be excluded but water can almost certainly penetrate.

For an FIP gasket liquid polyurethane is applied to one of the mating surfaces. As it cures a reaction makes it foam, producing a joint-free gasket. It’s a popular approach but tends to be messy and can be slow.

Die-cut gaskets are stamped from roll or sheet material and are the shape of the enclosure sealing face. The absence of joints means no leak paths. Material selection depends on applications requirements although neoprene or silicone are often good choices. Installation is just a matter of fitting them in place, usually with an adhesive.

Hennig Gasket & Seals can die-cut gaskets as large as 36″ x 62″. For larger gaskets flash (an oscillating knife,) or waterjet cutting are available.  Contact us Today.

How Hot is too Hot? Choosing the Right Gasket Material for a Non-Metallic Gasket

For non-metallic gasket applications, the operating temperature of the finished product is a major consideration. You need to know the temperature range (and other strengths and weaknesses) of potential materials so you can get the most durable custom gaskets and seals. Otherwise, they could prematurely harden, crack, deform and lose strength, elasticity and resilience, etc.

The following is a list of common non-metallic gasket materials, their properties and their most stable operating temperature ranges (in Fahrenheit). Understand that while there may be wiggle room on either end, it’s best to aim for somewhere in the middle of each particular material’s temperature range so that the gasket or seal performs optimally for the longest period of time before replacement is needed.

Nitrile: -30 to 250F (very resistant to oils, aromatic hydrocarbons, fuels and solvents).

Neoprene: -35 to 225F (resistant to weather, water, combustion and a long list of chemicals).

Polyurethane: -35 to 225F (resistant to oxygen, ozone, cracking, abrasion, cuts, grease and heavy loads; frequently used in machine mounts, electrical equipment wear pads and applications needing shock absorption).

Ethylene Propylene: -70 to 250F (resists severe weather conditions, acids, oxygen, alkalis, hot and cold water and ketones; not suitable for use with oils or fuels).

Fluorocarbon: -15 to 400F (its low friction and resistance to wear and tear make this a good material for gaskets that endure movement, a wide temperature variation and frequent reassembly).

Silicone: -65 to 450F (very resistant to hot, cold and oxygen, but poor resistance to oils and fuels; frequently used in food processing and medical applications).

Polytetrafluoroethylene: -238 to 574F (extremely wide temperature range, also stands up to harsh conditions of all sorts; frequently used in food processing, pharmaceutical, laboratory, semi-conductor, petrochemical and chemical and electrical applications).

Temperature range is, of course, just one aspect of a non-metallic gasket material that you will need to consider before project implementation; nevertheless, temperature tolerance is crucial. If you need custom gaskets and seals for your project, please call us at 1-800-747-7661 to discuss your needs with us.

Properties of Neoprene Gasket Material

Neoprene, which is also known as “polychloroprene,” is a type of synthetic rubber produced by the polymerization of chloroprene. Neoprene gasket material has become very common due to the fact that it resists the likes of ozone, sunlight, oxidation and many petroleum derivatives. Additionally, neoprene is characterized as being weather-, combustion-, water- and chemical-resistant. As you can see, it’s popular because it is resistant to many types of damages. What’s more, it’s also resistant to damage from twisting and flexing.

Here’s a closer look at the properties of neoprene so you can judge whether or not it’s a good material for your application:

  • Stretch and cushioning properties: Neoprene is elastic and form-fitting, able to conform to various sizes and shapes. It’s also cushioning, able to absorb shock.
  • Various grades available: From cloth inserted neoprene, which is reinforced with nylon for additional stability, to flame retardant neoprene, which passes a variety of flammability specifications, there are several grades available to suit any application. Other popular grades include commercial, FDA approved, diaphragm and high tensile strength.
  • General gauge thicknesses vary in size from 3/32-inch up to 2 inches.
  • Hardness ratings vary from 40 to 80.
  • Plate finish.
  • Neoprene can withstand temperatures ranging from -20 degrees F to 180 degrees F.
  • Tensile strength ranges from 900 to 1,000 PSI.
  • Elongation ranges from 350% to 400%.
  • Finally, widths are 36 inches, 48 inches or 72 inches.
  • Pressure sensitive adhesive, or PSA, are available upon request.
  • We fabricate neoprene gaskets through proven manufacturing processes that include waterjet cutting, flash cutting and die cutting.

One other neat feature about neoprene is that it’s impermeable, meaning that it can work as a tight barrier to prevent the escaping of gases or liquids.

For more information on the neoprene material and neoprene gaskets, and to speak with someone about placing an order, contact us today.

Three Ways to Make Gaskets Last Longer

Replacing gaskets is often costly. Unplanned downtime and maintenance hours dwarf the actual price of the gasket or seal, so you need it to last as long as possible. Gasket life depends very much on service conditions but there are things you can do to reduce the likelihood of premature failure.

1. Match the gasket material to the job.

Start by considering “TAMP.” This memory-jogging acronym stands for temperature, application, media and pressure. Specific factors to consider are: temperature of media (which should include any cleaning processes,) and the external temperature range, internal pressure, and the nature of the media itself, particularly whether it’s corrosive.

Look at the gap being sealed. Is it uneven? How often will the joint be opened? An enclosure gasket for an indoor electrical cabinet sees very different usage and conditions to what boiler seals endure.

Then select the gasket material. Conformable elastomers like NBR are a popular choice but are limited in temperature and pressure capability. EPDM and neoprene are often used for food grade gaskets as they clean easily. PTFE holds up well to corrosive media, graphite is soft and handles high temperatures.

2. Store gaskets correctly

Avoid exposure to sunlight as UV accelerates aging. Temperature extremes will do the same, so keep them away from heat sources and in winter protect them from freezing. Humidity can damage some materials too.

Don’t hang gaskets because they’ll stretch. Don’t place loads on them as the material may take a compression set. Rubber ages, so if possible, use date codes and discard after four years.

3. Use best-practice installation techniques

Clean surfaces thoroughly, then inspect for damage, especially any scoring that creates a potential leak path. Clean and lubricate bolt threads and heads to avoid making torque appear higher than what the joint actually sees. Seat the gasket carefully, then bring the joint together and follow best-practice methods for tightening.

Premature gasket failure often forces unplanned downtime, disrupting schedules and hitting capacity. Careful attention to gasket material selection, storage and installation reduces the likelihood of premature failure and all the costs that go with that.