H.B. Fuller FH8731

H.B. Fuller FH8731 is a one-part epoxy potting material designed for the encapsulation of electronic parts. It features easy handling due to its one-part formulation, good stability, and fast curing at medium temperature. It is typically used for the encapsulation and protection of electronic parts.

Chemical Family: Epoxides, Epoxy & Epoxy Derivatives

Product Type: 1K (1 component) Adhesive, Potting Compound, Reactive Adhesive

Application Area: Electronic Components, Encapsulant, Printed Circuit Boards

Features: Easy To Apply, Excellent Flowability, Fast Curing, Good Stability, High Reliability

Technical Data Sheet
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Enhanced TDS

Identification & Functionality

Features & Benefits

Ready-to-Use Product Features
Features and Benefits
  • 1K and no need mixing
  • Fast curing
  • Good storage stability
  • High flow ability and good reliability

Applications & Uses

Application Area
Typical Applications

Encapsulation and protection of electronics parts.

Directions for Use

1. Do not open the package before complete the thawing.
2. Thawing to room temperature (25°C) before using.
3. Seal any remaining material and store immediately at 2-8℃.
4. Preheating temp. to 30-45℃.


Physical Form
Black liquid
Electrical Properties
ValueUnitsTest Method / Conditions
Dielectric Constant (at 1KHz)3.3/0.018--
Dielectric Constant (at 100KHz)3.3/0.02--
Volume Resistivity4.1 x 10¹⁶Ω.cm-
Surface Resistivity1.3 x 10¹⁶ohm-
Dielectric Strength16.2kV/mm-
Cured Properties
ValueUnitsTest Method / Conditions
Hardness87.0-Shore D
Glass Transition Temperature129.0°C-
Coefficient of Thermal Expansion (Alpha 1)58.0m/m.°C-
Coefficient of Thermal Expansion (Aplha 2)185.0m/m.°C-
Water Absorption(24h)0.06%-
Uncured Properties
ValueUnitsTest Method / Conditions
Viscosity (Brookfield, spindle 7, 10 rpm)36400.0mPa.s-
Pot Life3.0months-

Technical Details & Test Data

Recommend Curing Profile

150℃ 20 min。
It depends on the heating efficiency and the thickness of PCB and size of die. We suggest to adjust curing temperature and curing time according to heating device and adherent.

Packaging & Availability

Regional Availability
  • Africa
  • Asia Pacific (Excluding Russia)
  • Europe (Excluding Russia)
  • India
  • Latin America
  • Middle East
  • North America

Storage & Handling

Storage Conditions

FH8731 is supplied in 500ml/barrels
It should be stored in 2-8°C refrigerator.
Shelf life is 12 months from date of manufacture.