Two component epoxy compound for high performance applications

Key Features

  • High temperature resistant
  • Lower viscosity
  • Robust chemical resistance
  • Very long open time
  • Superior physical strength properties
  • Meets NASA low outgassing

Product Description

Master Bond EP21H is a two component epoxy system with exceptionally good clarity and a unique optical transmission profile for an epoxy. Nearly all epoxies display minimal light transmission below 330 nm. EP21H has a special crosslinking profile that allows for exceptional light transmission in the 250-365 nm spectra. The light transmission in sections of 0.005 inch or less exceeds almost 95% from 260-2,000 nm. EP21H is easy to handle having a long open time. EP21H will cure at room temperature and it can be accelerated by adding heat. It bonds well to a wide variety of substrates including glass, many plastics, metals and composites. It resists many chemicals including water, oils and cleaning agents. Additionally, EP21H has low shrinkage upon curing, sound electrical insulation properties and a reliable array of physical strength attributes. The color of Part A is clear and Part B is light amber clear. The service temperature range is -60°F to +250°F. EP21H is primarily used in optical, fiber-optic, electro-optic and related applications where this very uncommon light transmission pattern for an epoxy type material is required.

Product Advantages

  • Relatively easy to manage 100:50 mix ratio by weight
  • Exceedingly long working life
  • Low viscosity; readily applicable for bonding, sealing, coating and encapsulating
  • Very good physical strength properties
  • Splendid electrical insulation properties
  • Very special optical transmission properties

Industrial Certifications

ASTM E595 Compliant

Meets EU Directive 2015/863



Double Barrel Cartridge

Gun Applicator


EP21H is available is various sizes and units to accommodate customer's needs.

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