This procedure covers epoxy mixing and handling. The epoxy covered by this procedure has multiple uses, including solder mask repair, base board repair, circuitry over-coating, and delamination repair.
Note: For high strength or high-temperature applications two-part epoxies will generally have the best properties.
Minimum Skill Level - Intermediate
Recommended for technicians with skills in basic soldering and component rework, but may be inexperienced in general repair/rework procedures.
Conformance Level - High
This procedure most closely duplicates the physical characteristics of the original, and most probably complies with all the functional, environmental and serviceability factors.
Foam Swab, Small
Swabs for use with solvents and application of color agents and epoxies.
Additional Items and Supplies
General purpose cleaner for removing contamination.
General purpose oven for drying, baking and curing epoxies.
Nonabrasive, low-linting wipes for cleanup.
Circuit Bond Epoxy
Circuit Bond is a clear, low viscosity, superior strength epoxy precisely measured out into two-compartment plastic packages, so it's easy to use, and there's no measuring. For over a decade, this high-strength epoxy has been qualified and used by thousands of high-rel electronics manufacturers across the globe.
Circuit Bond has a working pot life of 30 minutes. It should not be mixed until ready to use.
To use Circuit Bond, remove the plastic clip separating the resin and hardener. Squeeze back and forth from one half of the package to the other to mix the contents.
Cut a corner off the package and squeeze all the contents into a Plastic Cup. Stir the contents to ensure it is thoroughly mixed.
Circuit Bond may contain bubbles from the mixing process. If needed, use a vacuum system to remove bubbles.
Color Agent can be mixed in with Circuit Bond to match surface colors if desired.
Apply using a Foam Swab, Micro Probe, or Mixing Stick as required.
Cure Circuit Bond for 24 hours at room temperature or 4 hours at 65°C (150°F).
2 gram pre-measured packages
4 parts resin to 1 part hardener
Mix Ratio by Weight (R/H)
24 hours at room temp (25 °C) or 4 hours @ 65°C
Viscosity (after mixing)
Operating temperature range
-55°C to 135°C
88 Shore D
Lap Shear, Alum to Alum
Glass Transition Temperature, Ultimate
Coefficient of Expansion, cm/cm/°C
Dielectric Constant, 1KHz@25°C
6 months minimum
Color Agent is a one-part, air-drying, semi-paste ink commonly used to print hard surfaces, including circuit board base materials. Color Agent can be used to tint the color of epoxy used for solder mask repair or circuit baseboard repair. To use, mix a small amount of color agent with 2 part epoxy as the epoxy is initially mixed. Add more color agents to increase the color intensity if needed.
Figure 1: For prepackaged epoxy, remove divider clip and mix resin and hardener inside package.
Figure 2: Apply epoxy as needed. Foam swabs may be used to add texture for soldermask repair.
Epoxies used for circuit board repair and rework require specific properties. The Epoxy referenced in this procedure is a clear, low viscosity, superior strength two-part epoxy. It is available in two-compartment plastic packages, so no measuring is needed.
See the Related Products below for details about the Epoxy referenced in this procedure.
The area where the epoxy is to be applied should be prepared prior to mixing the epoxy. This preparation may include preheating the affected area to improve absorption of the applied epoxy. The entire circuit board may also be heated in an oven or with a heat lamp.
Caution: Some components may be sensitive to high temperatures.
Procedure - Prepackaged Two Part Epoxy
Remove the clip separating the resin and hardener. Mix by squeezing both halves together with your fingers. Mix for at least one minute to ensure a complete mix of the resin and activator. (See Figure 1)
Cut open one end of the epoxy tube and squeeze the contents into a mixing cup. Mix again with a mixing stick to ensure a thorough mixture of the resin and hardener.
Note: For bubble-free epoxy, remove the clip separating the resin and hardener. Cut open one end of the Epoxy tube and squeeze the contents into a mixing cup. Slowly stir the mixture with the mixing stick. Be sure to stir the mixture for at least 2 minutes to ensure that all the resin and hardener have completely mixed.
If needed, add a color agent to the mixed epoxy. Stir slowly to prevent bubbles.
Apply or use as needed. (See Figure 2)
Cure the epoxy for 24 hours at room temperature or 1 hour @ 165F (74C)
Visual examination of epoxy for texture and color match.