Replacing Soldering and Brazing with Thermally Conductive Epoxies

September 15, 2014

September 15, 2014 - For high heat electronics applications requiring a small footprint, bonded fin heat sinks are a good, reliable option. These heat sinks have separate fins attached to a base plate, eliminating many of the design limitations associated with extruded heat sinks.

Soldering and brazing are the two most common ways to fasten fins to the base. While effective, these methods can expose workers to unsafe, high-temperature working conditions. For a safer, easier alternative to soldering and brazing, consider using a high-thermal-transfer epoxy.

When formulated with the right heat dissipation characteristics and viscosity, aluminum-filled epoxies can be particularly well-suited for fin bonding. One such epoxy is our two-component 70-3812 NC product. Its specifications at 25ºC include:

  • Mixed viscosity: 8,000 cP.
  • Specific gravity: 1.81.
  • Durometer: 90 Shore D.
  • Tensile strength: 9,000 psi.
  • Compressive strength: 18,500 psi.
  • Operating temperature: -55 to 155°C.
  • Coefficient of thermal expansion: 28 x 10-6.
  • Thermal conductivity: 4.5 W/m·K.
  • Low outgassing as per ASTM E-595-07.

For more information on choosing the right adhesives for heat sink bonding, download our new application note.