How to Find the Right Gasket Sealants

When it comes to gaskets, using the right sealant to match the gasket and application is crucial and can even extend the life of a gasket. So, we’ve come up with a list of sealants that you should have on hand when working with an engine, transmission, differential, or minor repair.

  1. 1. Shellac is good for thin paper or cardboard gaskets mounted in low-temperature and/or low-pressure environments. It’s resistant to engine fluids, but not to many shop chemicals, so it’s commonly used for mounting thermostat, timing cover, or differential cover gaskets.
  2. 2. High Tack is a non-drying sealant used in similar applications to Shellac but can sustain temperatures of up to 500?. Because it is non-drying, it remains tacky and is resistant to kerosene, propane, and diesel fuels.
  3. 3. Form-a-gasket sealants are available in three forms, #1) fast-drying, fast-hardening; #2) slow-drying, non-hardening; and #3) brushable slow-drying, non-hardening. #1 is generally used for installing block expansion plugs, threaded connections, and to seal metal-to-metal flanges; #2 is used on cork and neoprene transmission pan gaskets; and #3 has the benefit of being brushable with various uses.
  4. 4. Copper gasket sealants are fast-drying and can help dissipate heat and promote even heat transfer between mating surfaces. They can also be used to fill small imperfections in metal surfaces. Because they can sustain up to 500?, they’re ideal for cylinder head and exhaust manifold gaskets.
  5. 5. Anaerobic sealants are designed to be used in applications where outside air is not available for the drying process. They’re good for side-of-the-road leak repairs, or places where there’s never been a gasket or a replacement is no longer available.
  6. 6. RTV Silicone sealants are good for up to 500?, 650?, and 750? based on the color. They’re effective sealants but can be used as a gasket themselves. There is also an “Ultra” RTV that is sensor-safe for newer electronic-controlled vehicle use.
  7. 7. Hylomar is a polyester urethane-based gasket compound able to sustain up to 500? without hardening or setting. Because it remains tacky, it makes repeated disassembly and reassembly easier. It can also replace a gasket.

At ASAP Aerospace, owned and operated by ASAP Semiconductor, we know the importance of a good sealant. So, as a premier supplier of aerospace and aviation parts and components, we made sure to stock the best gaskets parts and sealants at the most competitive prices. Just visit us at to get started. 


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