In a recent blog, we looked at selecting gaskets for strong acid service. Strong acids and bases (alkalies, or caustics) are commonly found corrosive substances. In this blog, we look at how to choose gaskets for strong caustic service.

Caustics are essentially bases dissolved in water. A base is a substance that can accept a hydrogen ion from another substance. Strong bases give off a hydroxide ion (OH-) when dissolved in water, forming alkaline solutions with a pH greater than 7.0. Strong alkalies, or caustics, include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (CaOH2), and others. These strong caustics have very high pH values. Because strong caustics are aggressive compounds that are extremely corrosive, achieving effective seals in applications which use these substances can be challenging.

Strong caustics are often used in applications within the following industries:

Choosing the right gasket for strong caustic service is important since seals that cannot withstand the aggressive chemical attack will likely fail, causing leaks and possible personal injury.

Gasket materials that can be used to produce gaskets for strong caustic service include the following:

CRG can supply gaskets produced from EPDM, FKM (including Viton®), PTFE, or other materials especially designed to handle strong caustic service. If you have a strong caustic application, our sales team will be pleased to review your needs and discuss the material options available. Contact our sales team directly at


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