April 2017

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.

What is Neoprene

Possibly the most widely used (and certainly the type we’re asked for most), neoprene gaskets are a good choice in many applications. However, they do have some limitations. It’s easier to understand when and when not to use neoprene gaskets if you know something about the material. Here we’ll answer: What is Neoprene? What makes neoprene so useful in many gasket applications? And when you should look for something else.

Rubber-Like Elastomer

In the 1930’s and ‘40’s scientists cooked up several types of artificial rubber. Styrene-butadiene rubber (SBR) and nitrile-butadiene rubber (NBR) are two of the best known. A third was neoprene. Like NBR and SBR, it’s mainly carbon and hydrogen, but has chlorine added to each molecule. That makes its chemical name chloroprene, or polychloroprene once polymerized. The ASTM D1418 designation for neoprene, which was DuPont’s tradename, is CR. The ASTM D2000 type and class is BC and BE, depending on the specific grade.

Useful Properties of Neoprene

The first ASTM D2000 letter tells us the upper-temperature limit of neoprene is 212°F (100°C). The lower temperature limit is around -30°F (-34°C), although neoprene becomes stiffer before getting that cold. The second letter indicates that it is prone to swelling when exposed to oils.

Neoprene does, however, resist attack by mineral and vegetable oils. It’s also resistant to ozone and weather aging, making it useful in outdoor applications.

It takes relatively little force to deform, which helps make neoprene gaskets versatile. Shore A durometer numbers are typically 50 – 70, meaning it’s quite soft. (Learn more about Shore and Durometers in, “Understanding Gasket Material Hardness” and “Measuring Gasket Material Hardness.”)

Neoprene Limitations

Aromatic hydrocarbons like benzene and toluene will degrade neoprene, as will ketones and chlorine-based chemicals. While it has many uses, neoprene should not be used with food.

Neoprene Material Forms

Neoprene gaskets are typically cut from sheet material. A range of thicknesses and hardnesses are available. Neoprene can also be foamed and is available in both open and closed-cell forms. This has the advantages of lower density and greater compressibility. Hennig material specialists can provide more details.  Contact us for your custom neoprene gasket material needs.