Nyseal Underhead Selant from PSM International
Nyseal Underhead Sealant is a pre-applied coating engineered to deliver reliable sealing under fastener heads without the need for additional gaskets, O-rings, or liquid sealants. Applied to screws, bolts, or similar components before assembly, this innovative solution ensures consistent sealing performance against fluids, dust, and gases—simplifying production and improving long-term joint integrity.
Advantages
> Eliminates time-consuming in-house applications of O-rings, gasket seals and sealant compounds
> Will not work loose
> Eliminates the leak path
> Prevents galvanic corrosion between dissimilar materials
> Reusable
> Highly durable
> NYSEAL’s green sealing element will not shrink or dry out from age
> Resistant to chemicals like alcohol, petroleum, oil, kerosene, diesel fuel and hydraulic fluids
> Working temperature: maximum 66°C (150°F)
> Screw strength is unaffected
> Assembly ready
Benefits
Nyseal was developed as a solution to a need for a highly durable fastener sealing element that could perform under high pressure and was resistant to a wide variety of chemicals. It eliminates the need and cost of secondary application during the assembly process.
PSM engineers are available to assist in recommending the correct sealant solution for your application.
Design & Application Guidelines
Surface Preparation
For best results, ensure the bearing surface beneath the fastener head is smooth and free of burrs or sharp edges that could damage the Nyseal Underhead Sealant layer. Even compression during tightening is key to achieving maximum sealing performance.
Assembly and Torque Control
When the fastener is tightened, the Nyseal Underhead Sealant compresses to fill surface voids and imperfections, creating a tight, gasket-like barrier. Because it’s pre-applied, it guarantees consistent results without the variability of manual application. In most cases, standard torque settings can be maintained, as frictional effects are minimal.
Durability and Reusability
Nyseal Underhead Sealant is designed for long-term resilience, maintaining sealing properties even after thermal cycling and vibration exposure. While it can often be reused after disassembly, it’s recommended to validate sealing performance for critical applications following multiple assembly cycles.
Applications and Industries
Nyseal Underhead Sealant is ideal for industries that demand dependable sealing performance—such as automotive, electronics, HVAC, fluid handling, and industrial manufacturing. It is particularly effective in assemblies exposed to vibration, moisture, or fluctuating temperatures, offering a clean, cost-effective alternative to traditional sealing methods.