Nyplas from PSM International
Nyplas is a plastisol (PVC-based) under-head coating applied to fasteners before assembly, designed to provide a reliable seal beneath screw or bolt heads. It seals against water, moisture, dust, and air and also helps with noise dampening. Because it is pre-applied, there is no need for separate gaskets, O-rings, or liquid sealants during assembly.
Key Features & Benefits
Provides a secure seal immediately upon tightening with no curing time required
Maintains elasticity and sealing integrity over time without shrinking or drying out
Suitable for use with various fastener types such as screws, studs, and rivet nuts
Compatible with metals like steel, aluminum, and stainless steel
Offers excellent resistance to vibration, fluids, and thermal cycling
Operates effectively between –40°C to +150°C
Can often be reused without significant loss in sealing performance
Design & Application Guidelines
Surface Preparation
Fastener surfaces must be clean and free of oils or contaminants to ensure strong adhesion of the Nyplas coating. Bearing surfaces and countersinks should be smooth to prevent damage to the sealant during compression.
Assembly & Installation
During tightening, the Nyplas layer compresses slightly to fill microgaps between the fastener head and the mating surface, forming a durable gasket-like barrier. This prevents leaks and contamination ingress even under high pressure or vibration. Because the coating is pre-applied, no extra sealing compound is needed during assembly. Standard torque specifications can typically be maintained since the coating does not significantly alter friction levels.
Durability & Reuse
Nyplas under-head sealants are engineered to provide long-term performance, resisting aging, cracking, and shrinkage. In many applications, they maintain sealing performance even after multiple reassemblies. For critical systems, however, it is recommended to verify sealing integrity through standard quality tests.
Technical Data
