How low can gasket materials go?
Every rubber material has a glass transition temperature, or Tg. Below that point, the polymer chains lock up and the material goes from flexible to glassy and brittle. When a gasket hits its Tg, it loses the ability to conform to flange surfaces and maintain sealing pressure. That is when leaks happen. So when I talk about a low temp rubber gasket, I am really talking about a material with a Tg low enough to stay rubbery at the operating temperature. The lower the Tg, the colder the environment the gasket can handle.
Silicone: the low temp rubber gasket workhorse
Silicone is usually my first recommendation for cold temperature sealing. Standard silicone has a Tg around -80F to -100F, which means it stays flexible well below what most applications require. We cut a lot of low temperature silicone gaskets from materials qualified to AMS-3334 and AMS-3335, as well as A-A-59588 (formerly ZZ-R-765). For truly extreme cold, phenyl silicone grades replace some methyl groups with phenyl groups in the polymer backbone, pushing the Tg below -150F. Standard silicone gaskets handle most cold applications, but if you are pushing toward cryogenic territory, ask about phenyl silicone.
Fluorosilicone: extreme cold plus fluid resistance
Fluorosilicone gives you essentially the same low temperature range as standard silicone, but adds fuel and solvent resistance. That combination is rare. Most elastomers that resist fuels, like nitrile or fluorocarbon, lose low temperature flexibility fairly quickly. Fluorosilicone keeps it. We cut fluorosilicone gaskets from materials qualified to AMS-3323, and they are common in aerospace fuel system sealing where both extreme cold and fluid exposure are present.
EPDM for cold temperature applications
EPDM is a solid mid-range option for cold temperature gasketing. Its low temperature performance varies with ethylene content, but most commercial EPDM compounds are good down to around -40F to -60F. Not as impressive as silicone, but plenty for many outdoor applications. Where EPDM shines is UV, ozone, and water resistance, which makes EPDM gaskets a great choice for outdoor enclosures that see cold weather but not cryogenic temperatures. EPDM is available in solid, sponge, and foam forms.
Nitrile and other elastomers in cold environments
Nitrile rubber (Buna-N) has a low temperature limit that depends on acrylonitrile (ACN) content. Higher ACN gives better oil resistance but worse cold flexibility. Lower ACN improves cold performance but sacrifices some oil resistance. Most standard nitrile gaskets are good to around -30F to -40F, limited compared to silicone. Neoprene and fluorocarbon (Viton) are even more restricted in cold. For a broader look across the temperature spectrum, see our high temperature gaskets page.
Comparing gasket temperature ranges
|
Material |
Approximate low temp limit |
Key advantage |
|---|---|---|
|
Standard silicone |
-80F to -100F |
Best all-around low temp performance |
|
Phenyl silicone |
-150F or lower |
Extreme cold, cryogenic applications |
|
Fluorosilicone |
-80F to -100F |
Low temp plus fuel and solvent resistance |
|
EPDM |
-40F to -60F |
UV, ozone, and water resistance |
|
Nitrile (low ACN) |
-30F to -40F |
Oil resistance at moderate cold |
|
Neoprene |
-20F to -40F |
Moderate cold, moderate oil resistance |
If extreme cold is your primary concern, silicone and fluorosilicone are the clear leaders. EPDM works for moderate cold with the bonus of weather resistance. For cold flexibility plus softness, a soft gasket material like silicone foam or sponge works well. If fungus resistance matters in cold, damp environments, see fungus resistant gaskets.
More information on low temperature gaskets
If you need a gasket that will hold up in extreme cold, we stock and cut low temperature materials including silicone, fluorosilicone, and EPDM in solid, sponge, and foam forms. We can help you select the right material and provide samples. For questions or quotes, contact sales@nedc.com.
What gasket material works best in extreme cold?
Silicone is the best gasket material for extreme cold, with a glass transition temperature around -80F to -100F for standard grades and below -150F for phenyl silicone. Fluorosilicone offers similar low temperature performance plus fuel and solvent resistance.
What is the temperature range of silicone gaskets?
Standard silicone gaskets typically have a functional range of about -80F to +500F. Phenyl silicone grades can extend the cold end to -150F or lower. The exact range depends on the compound and whether the material is solid, sponge, or foam.
How does fluorosilicone perform in cold temperatures?
Fluorosilicone performs similarly to standard silicone in cold, with a low temperature limit around -80F to -100F. Its advantage is resistance to fuels, solvents, and hydraulic fluids, making it ideal for aerospace fuel system applications where cold and fluid exposure are both present.
What is a low temp rubber gasket?
A low temp rubber gasket is a sealing material designed to remain flexible and maintain sealing pressure well below freezing. These gaskets are made from elastomers with low glass transition temperatures, such as silicone, fluorosilicone, or specially formulated EPDM, to prevent the gasket from becoming brittle and losing its seal.