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2.3.3 Coating Removal, Peeling Method

 
Outline
This peeling removal method for coating can be used only under special circumstances. Normally this method is used to remove RTV silicone or other thick rubbery-like coating materials.

The coating material is removed using a dull knife or otherwise dull blade to slit the coating material and peel it off the printed board or printed board assembly.

To determine the appropriate coating removal procedure, the coating must first be identified. Refer to procedure number 2.3.1.

Note: This method is limited to coatings that are rubbery in nature to allow the coating material to be slit into small sections and peeled off the printed board assembly.

Minimum Skill Level - Advanced
Recommended for technicians with soldering and component rework skills and exposure to most repair/rework procedures, but lacking extensive experience.

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.

Acceptability References
IPC-A-600 2.0 Externally Observable Characteristics
IPC-A-610 10.0 Laminate Conditions
Procedure References
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
2.4.2 Coating Replacement, Conformal Coatings/Encapsulants
IPC 7721 3.3 Coating Removal, Peeling Method
Kits and Systems
201-7100
Precision Tool Set
Nine precision-crafted tools for detailed circuit board work.
Tools and Materials
355-0614
Knife with #16 Blades
A must-have tool for precise cutting, scraping and trimming.
335-3197
Scraper, Curved Tip
Hardened stainless steel tip for scraping solder mask and removing defects.
Additional Items and Supplies
Thermal Tool
Thermal Parting Tool
Thermal removal tool using controlled heat through specially shaped tips.
Images and Figures
2.3.3 Coating Removal, Peeling Method
Coating Removal Required At Outlined Area
2.3.3 Coating Removal, Peeling Method
Figure 1: Slit and peel off coating using a knife or heated blade.
2.3.3 Coating Removal, Peeling Method
Figure 2: Removal complete.

Procedure
  1. Slit and peel off the coating material with a dull knife or heated dull blade. (See Figure 1)
  2. Repeat as needed until the required material is removed.
Evaluation
  1. Visual examination or UV light may be used to verify complete removal of coating.
Procedure for reference only.