Two component epoxy for potting, encapsulation, coating and sealing applications

Key Features

  • Thermally conductive
  • Electrically insulative
  • Very long open time
  • Excellent temperature resistance
  • Outstanding dimensional stability
  • Passes NASA low outgassing test

Product Description

Master Bond EP121AO is a two component, high performance epoxy resin system featuring top notch temperature resistance, impressive thermal conductivity, superior electrical insulation properties and outstanding dimensional stability. It has an easy to use 100:80 mix ratio by weight. After mixing EP121AO is a lower viscosity epoxy with wonderful flow properties for coating, sealing, potting and encapsulation applications. Adhesion to metals, composites, glass, ceramics and many rubbers and plastics is first rate. As mentioned previously its salient features include prominent thermal conductivity, reliable electrical insulation properties and striking dimensional stability. The service temperature range is -60°F to +500°F. EP121AO features an extremely long open time of 1-2 days but requires oven curing. A typical cure schedule is 2-3 hours at 250°F followed by 5-8 hours at 300°F with a 2 hour or longer post cure at 350°F, although, a number of variations are possible. It also should be noted that EP121AO has exceptionally low exotherm upon curing and is an excellent fit for larger sized encapsulation or potting applications. The color of Part A is white, and Part B is tan. Other colors are available as well. EP121AO is most commonly used in electronics as a potting and encapsulation material when the combination of properties mentioned above is desirable.

Product Advantages

  • Medium viscosity, good flow
  • Very long working life
  • Exceptional dimensional stability
  • High thermal conductivity and excellent electrical insulation
  • Very low coefficient of expansion
  • Passes fungus resistance MIL-STD-810G

Industrial Certifications

ASTM E595 Compliant

MIL-STD-810G for Fungus Resistance

Meets EU Directive 2015/863




EP121AO is available is various sizes and units to accommodate customer's needs.

Request Information