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Fish Paper

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Fish paper is a durable, flexible, electrical insulator that’s made of vulcanized fiber and used with motor windings and for gasket insulation. A lightweight dielectric paper, this electrical grade material is also a good choice for oil-filled transformers. Moisture absorption can cause fish paper to swell or curl.

Interstate Specialty Products die cuts fish paper insulation for medical and scientific, electronics, and industrial applications. For over 50 years, our Made in the USA manufacturing company has been die-cutting electrical insulation materials at our custom fabrication facility in Sutton, Massachusetts.

Advantages of Fish Paper

  • outstanding dielectric properties
  • fish paper electrical insulation has good mechanical strength because it’s fibrous
  • this hard, wear-resistant cellulosic paper is more heat-resistant than many plastic materials
  • retains greater flexibility than plastics at low temperatures


Interstate Specialty Products can die cut insulation from rolls or sheets, and from various grades of fish paper. For example, flame-retardant electrical insulation materials that comply with UL-94 and ASTM D-635 standards are used in components such as wear plates, arc chutes, and circuit breaker baffles.  

Fish papers that incorporate mica layers for increased dielectric strength are also available. Ask Interstate Specialty products which type of electrical insulator is right for your application, and how our die cutting services can produce a range of part sizes to exacting tolerances.

Interstate Specialty Products is ready to answer all of your questions about types of insulation for your specific application. To learn more about our custom insulation manufacturing capabilities, contact us on-line or call (800) 984-1811.
*Properties and applications shown throughout this website are typical.  Your specific application should not be undertaken without independent study and evaluation for suitability.