Cork Gaskets

Silicone or Traditional Gasket Material for Oil-Tight Joints?

Sep 08, 2026

For many years, oil-tight joints have been achieved with either cork or NBR gaskets. Today though, as silicone is being used in an ever-growing list of applications, is it time to switch? Here’s a look.

Silicone Strengths

Characteristics of silicone that make it an excellent gasket material include:

  • Wide temperature range (-60° to 480°F)
  • Available in very soft grades (down to 10 Shore A)
  • Good compressibility and compression set resistance
  • Compatibility with an extensive catalog of chemicals
  • Available in a range of colors and FDA-approved grades for food and medical uses
  • Good ozone, UV and weathering resistance

Cork as a Gasket Material

Natural cork was one of the first gasket materials, and in some regards, still performs well. It compresses readily and resists water and many chemicals. Today, cork is often mixed with neoprene or nitrile rubber for better sealing behavior. A major limitation is a working temperature range of -22° to 212°F.

Properties of NBR for Gaskets

NBR, also known as nitrile and Buna-N, was one of the first synthetic rubbers. Like silicone, it has good compressibility and recovery. Its temperature range is -40° to 226°F.

NBR resists attack by a long list of chemicals, including lubricating and hydraulic oils. It is however, damaged by UV and ozone, so is best used indoors rather than out.

Can Silicone Replace NBR and Cork?

One of silicone’s few weaknesses as a gasket material is susceptibility to gasoline, lubricating oils, and anything else containing hydrocarbons. In addition, its resistance to hydraulic oil is only fair.

So, the answer is, to create oil-tight seals, stick with a traditional gasket material. NBR is almost always a good choice, providing it can handle the expected temperatures.

Ask Hennig About Oil-Resistant Gasket Material

Oil leaks are messy and potentially dangerous. The secret to oil-tight joints is to use the correct gasket material. While silicone is an excellent choice for many applications, it doesn’t hold up well to lubricating oils, so it’s better to stick with the traditional materials.

As always, for advice on any aspect of gaskets and seals, contact our experts on 1-800-747-7661 or via our website.

Cork Gaskets, Silicone Gaskets
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Synthetic Cork for Gaskets: Advantages & Properties

Apr 01, 2024

Cork is one of the oldest gasket materials, but it still has a role in sealing applications. It’s a flexible, closed-cell material that resists water and oil, and has excellent compressibility. However, as a natural material – cork is the bark of the cork oak tree – it can vary in quality. It’s also susceptible to various types of mold.

Synthetic cork is intended to have the same wide set of useful properties but without these limitations.

Composition Cork Vs. Cork Rubber

The natural cork used for gaskets is almost always composition cork. This is a conglomeration of cork particles held together with a binder. It’s produced in sheets up to ¼” thick and is usually die cut to produce gaskets.

The synthetic cork used for gaskets, also known as rubberized cork or cork rubber, improves upon composition cork by adding an elastomeric material. Rubberized cork is usually composed of 70% natural cork particles and 30% neoprene or NBR.

In addition to its role as a gasket material, natural cork has long been used as a stopper for wine bottles. In recent years supply shortages and problems resulting from natural variability have prompted development of synthetic cork. Made primarily from polyethylene, this works for sealing bottles, but isn’t going to make good gaskets.

Properties of Rubberized Cork

Neoprene resists oils and greases. Cork made with NBR resists these plus fuels and many solvents. The upper temperature limit for both is 250 °F.

Good applications are those that need a very compressible material. Flanges with uneven surfaces and those made from material that deforms under load are often best sealed with rubberized or synthetic cork gasket material.

Hennig, For All Your Gasket Material Needs

When replacing a gasket it’s usually best to stick with the material that came out. If that looks like a composition or synthetic cork, we can help. We carry rubberized gasket material in sheet and roll form, up to 48” wide and ¼” thick. Synthetic cork is readily die cut to the shape needed. Contact us for a quote.

Cork Gaskets
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