Circuit Board Repair Guide > Base Board Repair > 3.5.1 How to Repair Minor Damage to Circuit Base Board Material

How to Repair Minor Damage to Circuit Base Board Material

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 covers the repair of minor damage to circuit base board material. Scrapes and scratches in the base board material could be caused by accidents during handling. Burns in the base board material could be caused by improper use of soldering and desoldering tools.

Caution
This method may be used when the damage extends deep into the base material, but not completely through. If the base board material is damaged completely through, see Procedure No. 3.5.2 or 3.5.3.
 
Damaged circuit base board material needs repair
Damaged Base Material

Caution
Surface circuits may need to be replaced in the damaged area. Be sure that the appropriate circuit diagrams, or photographs reflecting the original circuits are available so that they may be replaced after repairing the base board material. Damage to internal circuits or planes may have to be restored using surface wires.

IPC Acceptability References
IPC-A-600 2.0 Externally Observable Characteristics
IPC-A-610 10.0 Laminate Conditions
 
Related Procedure Reference
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
IPC 7721 3.5.1 Base Material 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.
Foam Swabs - Ideal for absorbing cleaning solvents, and applying color agents and epoxies.
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.
Microscope - It is a challenge to undertake precision repair without a good microscope.
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.
Mixing Picks - Unique mixing sticks have a paddle shape on one and sharp pick on the opposite end.
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.

3.5.1 Base Material Repair, Epoxy Method

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

Scrape away damaged base board material

Figure 1: Scrape away damaged
base board material with a knife.


1.  Clean the damaged area.
 
2.  Scrape away the damaged base board material using a knife. All damaged base board material and solder mask must be removed at the surface. (See Figure 1).



or
Micro Drill System used for milling, drilling, grinding, cutting and sanding circuit boards

Figure 2: Micro Drill System.


    Mill away the damaged base board material using the Micro Drill System and ball mill. All damaged base board material and solder mask must be removed. (See Figure 2).

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.
 
    Caution
Abrasion operations can generate electrostatic charges.
   
An undercut to enhance mechanical strength

Figure 3: An undercut, to enhance mechanical strength, may be
desired for class 3 product.

    Note
An undercut to enhance mechanical strength may be desired for class 3 product. (See Figure 3).
 
3.  Remove all loose material and clean the area.

4.  Where needed, apply High Temperature Tape to protect exposed parts of circuit board.

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.
 
5.  Mix the epoxy. If desired, add color agent to the mixed epoxy to match the PC board color.
 
Apply epoxy with sharpened stick

Figure 4: Apply the epoxy with a
mixing stick sharpened at the end.


6.  Fill the area with epoxy up to and flush with the circuit board surface. No fibers of laminate material should be exposed. A mixing stick sharpened at the end may be used to apply and spread the epoxy. For large areas, apply the epoxy with a foam swab to create a texture in the surface. (See Figures 4 and 5).

Note
A slight overfill of epoxy may be desired to allow for shrinkage when epoxy cures.

Note
Epoxy may be applied using a foam swab to restore the surface appearance.
Apply epoxy with foam swab

Figure 5: For large areas, apply
the epoxy with a foam swab to
create a texture.
7.  Cure the epoxy per Procedure 2.7 Epoxy Mixing and Handling.

Caution
Some components may be sensitive to high temperature.
 
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 PC board surface.
 
10. Remove all loose material. Clean the area.

Note
If needed, apply an additional thin coating to seal any scraped areas.
 
Evaluation
 
1.  Visual examination for texture and color match.
 
2. Electrical tests to conductors around the repaired area as applicable.
 
3. No excess epoxy covering circuits or sensitive areas.
 
4. Epoxy fully bonded. No evidence of chipping.



Special Order. Usually ships within 3 business days. Ships From: Haverhill, MA, USA.

How to purchase. For customer service call 1-519-651-3060.
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.

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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.



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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

 
Foam Swab Foam Swabs, 3/16" Tip (pkg. of 100), 235-2102-100

Foam Swabs have 3/16" tip. Ideal for absorbing cleaning solvents, and applying color agents and epoxies.


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235-2102-100

$49.50 pkg/100

 
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.


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355-0614

$9.95 each

 
Mixing Pick Mixing Picks (package of 100), 115-3315-100

Unique mixing sticks have a paddle shape on one end for mixing, and sharp pick on the opposite end.


Enlarge
115-3315-100

$9.50 pkg/100

 
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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