Circuit Board Repair Guide > Base Board Repair > 3.3.1 How to Repair Minor Damage to Non-Plated Holes

How to Repair Minor Damage to Non-Plated Holes

Repair Circuit Boards | Repair SMT Pads | Repair BGA Pads | Repair Lands | Repair Edge Contacts
Repair a Conductor | Plated Hole Repair | Base Board Repair | Replace Solder Mask or Coatings

This procedure is used to repair cosmetic defects or minor damage to an unsupported tooling or mounting hole. The hole may have component leads, wires, fasteners, pins, terminals or other hardware running through it. This circuit board repair procedure uses high strength circuit board epoxy to restore the damaged surface surrounding the hole. This procedure can be used on single sided, double sided or multilayer printed circuit boards and printed circuit board assemblies.

Caution
Damaged inner-layer connections may require surface wire adds.

IPC Acceptability References
IPC-A-610 2.0 Externally Observable Characteristics
IPC-A-600 10.0 Laminate Conditions
 
Damaged hole in base board needs repair
Damaged Hole

Related Procedure References
CTC 1.0 Foreword - Circuit Board Repair Guide
CTC 2.1 Handling Electronic Assemblies
CTC 2.2.1 How to Clean a Circuit Board
CTC 2.2.2 Cleaning Circuit Boards, Aqueous Batch Process
CTC 2.5 Baking and Preheating of Printed Circuit Boards
CTC 2.7 Epoxy Mixing and Handling
IPC7721 3.3.1 Hole Repair, Epoxy Method

Tools and Materials
Alcohol Swabs - Self-saturating Isopropyl alcohol swabs. Squeeze handle to release alcohol.
Circuit Bond Pack - Clear, superior strength epoxy in two-compartment plastic package.
Cleaner - General purpose cleaner for removing contamination.
Cleaning Brushes - Disposable brushes for use with solvents for cleaning and application of coatings.
Color Agents - Use to tint the color of epoxy used for solder mask repair or circuit base board repair.
High Temperature Tape Discs - High temperature polyimide tape discs, .50" diameter.
Knife with #16 Blades - A must-have tool for precise cutting, scraping and trimming.
Micro Drill System - Versatile power tool for milling, drilling, grinding, cutting and sanding circuit boards.
Ball Mills, Abrasives, Cutting Tools - Ball mills, abrasives and cutting tools for working on circuit boards.
Oven - General purpose oven for drying, baking and curing epoxies.
Scraper - Hardened stainless steel tip for scraping solder mask and removing defects.
Wipes - Nonabrasive, low-linting wipes for cleanup.

3.3.1 Hole Repair, Epoxy Method

Printed Board Type: R/W  |  Skill Level: Advanced  |  Conformance Level: High  |  Rev.: D  |  Rev. Date: Jul 7, 2000

Mill away damaged material with Micro Drill

Fig. 1: Mill away damaged material with the Micro Drill and ball mill.






1.    Clean the area.
 
2.  Mill away the damaged board base material using the Micro Drill and ball mill. All damaged base board material and solder mask must be removed. No fibers of laminate material should be exposed at the surface perimeter of the hole. (See Figure 1).
 
  Note
To clearly see that all damaged material has been removed, flood the area with alcohol or solvent. Damaged internal fibers of the base material will show up clearly.
 
3.  Remove all loose material and clean the area.
 
4.  Where needed, apply High Temperature Tape to protect exposed parts of the circuit board. Tape may be required inside the hole. If epoxy reduces the inside diameter, the hole may have to be redrilled after the epoxy has cured.
 
  Note
The circuit board may be preheated prior to filling the area with epoxy. A preheated PC Board will allow the epoxy to easily flow and level out. Epoxy applied to an unheated circuit board may settle below the circuit board surface as the epoxy cures.
 
  Caution
Some components may be sensitive to high temperatures.
 
Apply epoxy with sharpened stick

Fig. 2: Apply epoxy with a mixing
stick sharpened at one end.

5.  Mix the epoxy. If desired, add color agent to the mixed epoxy to match the PC board color.
 
6.  Coat the area with epoxy up to and flush with the circuit board surface. A mixing stick may be used to apply and spread the epoxy. (See Figure 2).
 
  Note
A slight overfill of epoxy may be desired to allow for shrinkage when epoxy cures.
 
7.  Cure the epoxy per Procedure 2.7 Epoxy Mixing and Handling.
 
8.  After the epoxy has cured, remove the tape.
 
9.  If needed, use a knife or scraper and scrape off any excess epoxy. Scrape until the new epoxy surface is level with the surrounding circuit board surface.
 
  Note
Apply surface coating to match prior coating as required.
 
10.  Remove all loose material. Clean the area.
   
Micro Drill System used for milling, drilling, grinding, cutting and sanding circuit boards

Fig. 3: Micro Drill System.
Evaluation
   
1.  Visual examination for texture and color match.
   
2.  Hole size measurement to specification.
   
3.  Electrical tests to conductors around the repaired area as applicable.


Special Order. Usually ships within 3 business days from Haverhill, MA, USA.   For customer service call 1-519-651-3060.

How to purchase.                                                           View cart Minimum order $50 + shipping
Image Description Part No., Price and Quantity
Alcohol Swab Alcohol Swabs (package of 50), 235-1000-50

Self-saturating foam swabs filled with 99% Isopropyl alcohol. Ideal for removing flux residue and cleaning surfaces prior to soldering, coating and application of epoxy. Overall Length: 4.125". Squeeze handle until it "pops" releasing alcohol into the tip.

Enlarge
235-1000-50

$39.00 pkg/50

 
Liquid circuit board epoxy Circuit Bond Pack  MSDS, 115-3302

Clear, low viscosity, superior strength epoxy, precisely measured out into a two-compartment plastic package so it's easy to use and there's no measuring (2 gram). Shelf life: 6 months minimum.

Enlarge
115-3302

$12.95 each

 
Cleaning Brush Cleaning Brushes (package of 100), 235-2106-100

Disposable brushes for use with solvents for cleaning and application of coatings.



Enlarge
235-2106-100

$29.95 pkg/100

 
Color Agents for Circuit Boards Color Agent, Green, 115-9348

Use to tint epoxy for solder mask and base board repair. Color agent may also be applied directly to the circuit board surface for color matching. Supplied in 1 oz. (29 ml) collapsible metal tubes. MSDS

115-9348

$19.95 each

 
Color Agents for Circuit Boards Color Agent, Light Green, 115-9358

Use to tint epoxy for solder mask and base board repair. Color agent may also be applied directly to the circuit board surface for color matching. Supplied in 1 oz. (29 ml) collapsible metal tubes. MSDS

115-9358

$19.95 each

 
High Temperature Tape Discs 235-3050 High Temp. Tape Discs, .50" Diameter, 235-3050

High temperature tape discs are made of polyimide film with 1.5 mil of silicone adhesive that will not leave any residue. They can withstand temperatures of up to 500°F (260°C).
235-3050

US $5.95 pkg/60

 
Knife 355-0614 Knife with #16 Blades, 355-0614

A must-have tool for precise cutting, scraping and trimming. Includes five #16 blades.


Enlarge
355-0614

$9.95 each

 
Scraper 335-3197 Scraper, 335-3197

Hardened stainless steel tip for scraping solder mask and removing defects.



Enlarge
335-3197

$9.95 each

 

Products above ship direct from manufacturer and are special order/non-returnable. Will ship within 3 business days.



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Links to Related Products


Base Board Repair Kit used to repair damage to base board material   Base Board Repair Kit 201-3110
Most types of damage to base board material can be repaired with this versatile base board repair kit. The kit is industry approved and meets IPC guidelines. The kit includes epoxies and color agents. The high strength, high temperature epoxy withstands demanding physical environments.


Micro Drill System used for drilling, grinding, cutting circuit boards   Micro Drill System 110-4105
The Micro Drill System is a repair technician's dream and is ideal for milling, drilling, grinding, cutting and sanding circuit boards. It removes coating, cuts circuits, cuts leads, drills holes, cuts slots, shapes FR4 and performs many other procedures using various interchangeable bits. Unlike most hand-held tools, the Micro Drill has a tiny, high speed DC motor in the hand piece, eliminating cumbersome drive cables and giving you better control. A separate power supply keeps the hand piece lightweight and reduces operator fatigue. Base unit has controls for forward/reverse and speed up to 45,000 RPM.



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