Printed Board Type: R/F/W/C
Skill Level: Intermediate
Conformance Level: High
Revision: D
Revision Date: Coating Replacement, Conformal Coating, Encapsulant

OUTLINE
This method is used to replace conformal coatings and encapsulants on circuit boards.

ACCEPTABILITY REFERENCES
IPC-A-600 2.0	Externally Observable Characteristics
IPC-A-610 10.0	Laminate Conditions
PROCEDURE REFERENCE
1.0	Foreword
2.1	Handling Electronic Assemblies
2.2	Cleaning
2.3.1	Coating Removal, Identification Of Coatings
2.4.1	Coating Replacement, Solder Mask
2.5	Baking and Preheating
2.7	Epoxy Mixing and Handling
IPC7721 2.4.2	Coating Replacement, Conformal Coatings/Encapsulants

Conformal Coating Required At Outlined Area

TOOLS & MATERIALS
Brushes
Color Agents
Cleaner
Epoxy
Foam Swabs
Heat Lamp
Microscope
Oven
Replacement Coating
Wipes

PROCEDURE

1. Figure 1: For large surfaces, apply the replacement coating with a foam swab to create a texture.

   Clean the area.
   
   CAUTION
   Surfaces to be coated must be thoroughly cleaned prior to coating to ensure adequate adhesion, minimized corrosion, and optimized electrical properties.
   
   
2. If needed, apply Kapton tape to outline the area where the coating will be applied.
   
   
3. If required, bake the circuit board prior to the application of the replacement coating.
   
   
4. Mix the replacement coating.
   
   

5. Figure 2: Coating complete.

   Apply the replacement coating to the board surface as required. A brush or foam swab may be used to apply and spread the replacement coating. (See Figure 1).
   
   
6. Cure the epoxy per Procedure 2.7 Epoxy Mixing and Handling
   
   CAUTION
   Some components may be sensitive to high temperature.
   

EVALUATION

1. Visual examination for texture, color match, adhesion and coverage.
   
   
2. Electrical tests to conductors around the repaired area as applicable.