Paint Defects and Damage. Description and Operation

Damage Diagnosis and Assessment

Paint damage, regardless of its cause, is a routine part of work in the paint shop. Correct assessment of damage and determination of its cause are prerequisites for a professional paint repair solution.

Paint problems may still occur for various reasons, despite improved paint materials and new spraying methods.

Diagnosis is best performed in daylight, but not in direct sunlight. An accurate assessment can also be made under artificial fluorescent lighting.

Paint Damage Guide

The most important paint damage conditions requiring paint repair are:

• Biological contamination damage to paint, such as bird or insect droppings and tree resin.
• Environmental paint damage caused by acid rain.
• Metal particles embedded in the paint surface caused by rail dust during vehicle transport or deposition of factory emissions.
• Chemical paint damage caused by industrial contaminants such as smoke, fuel, acids, and oils.
• Mechanical damage caused by stone impacts during operation, scratches from car washes and parking.
• Damage caused by application errors. Application defects such as runs or orange peel.
• Dirt inclusions in the paint layer, e.g. due to dust in the topcoat or textile lint.
• Damage due to corrosion.

Before repairing such paint problems, an accurate diagnosis must be carried out to determine the cause precisely. On-site diagnosis using simple aids and processes is often sufficient.

Non-destructive paint diagnosis is performed by:

• Feeling embedded particles with a flat hand.
• Visual inspection without visual aids, under suitable lighting conditions, at a suitable angle and from the correct distance.
• Visual inspection using a magnifying glass.
• Measuring film thickness with magnetic coating thickness gauges for steel panels.
• Electronic measurement of film thickness on steel and aluminum panels, as well as plastic components.

A preliminary test method is the fingernail test. With suitable experience, the existing paint hardness can be determined.

Test methods that partially destroy the paint:

• Adhesion test using adhesive tape.
• Cross-cut hatch test procedure to check adhesion strength.

In certain circumstances these test methods are not sufficient for a definitive diagnosis. In this case, paint diagnosis must be carried out under controlled conditions.

Measuring and Testing Equipment for Painted Surfaces

• Coating thickness measuring instruments
• Magnifying glass
• Suitable photographic equipment with macro lens

Paint damage caused by environmental factors

In all paint damage cases described below, if the damage is irreversible, a new paint coating must be applied.

• Bird droppings
• Insects
• Tree resin and sap
• Tar spots
• Rust film / deposits from industrial fallout
• Battery Acid
• Brake fluid

Paint damage from bird droppings

Damage from bird droppings most often appears as dull, etched areas of the topcoat of various sizes. If left on the vehicle for a long time, cracking and etching into the substrates may occur.

Cause/nature of damage:

• Bird droppings are especially harmful in combination with heat and moisture. Urea (white part) has a very high salt content and is very aggressive.
• The severity of the damage varies depending on the type, amount, contact time and concentration.
• The result is cracking, etching, and marks up to dissolution of the clear coat.

Repairing the damage:

• Clean with Motorcraft® Bug and Tar Remover.
• If the damage is minor, polish the area.

Paint Damage Caused by Insects

On the areas where insects have impacted the hood, roof and bumper, there are small etches or etched paint marks with partially visible stain marks.

Cause/nature of damage:

• The clear coat is quickly destroyed by swelling and etching of the surface.
• Insects that strike the vehicle stick to the paint surface. Combined with moisture and heat, the acids formed from the insect bodies penetrate into the clear coat.
• The etching is usually only a few millimeters thick.

Repairing the damage:

• Clean the affected area with Motorcraft® Bug and Tar Remover.
• Wash with Motorcraft® Detail Wash.
• Protect with a hard wax.
• If washing the vehicle does not remove the damage, polish the area.

Paint Damage Caused by Tree Resin or Sap

Small yellow-brown spots or drops on horizontal surfaces of the vehicle. The drops melt in the sun. Resin damage occurs only during the warm summer months.

Cause/nature of damage:

• Due to their chemical composition, tree resins bond very strongly to the clear coat layers and cause them to wrinkle. The higher the temperature, the stronger the chemical bond between the resin and the clear coat surface.

Repairing the damage:

• Use Motorcraft® Bug and Tar Remover, following the manufacturer's recommendations.
• Final cleaning with a wax and grease remover.
• If chemical cleaning does not remove the damage, polish the area.

Paint Damage Caused by Resin Stains

Yellow or dark stains.

Cause/nature of damage:

• Firmly adhered resin stains that cause discoloration of the surface. In some cases, penetration through the clear coat into the base coat.

Repairing the damage:

• Clean the painted surface with Motorcraft® Bug and Tar Remover, following the manufacturer's recommendations, and polish.

Rust Film / Industrial Fallout Deposits

Small round marks about 1 mm in size, in all shades from black, gray and blue to reddish, on horizontal surfaces of the vehicle.

Cause/nature of damage:

• Deposits from liquid-fuel systems and industrial plants, especially in high humidity and inversion weather conditions, cause damage to the clear coat.
• As the exposure time increases, so-called rust halos form. They spread as long as the deposits continue to corrode.
• Iron-containing industrial fallout will not be removed within a few days!

Repairing the damage:

• 
  For additional information, refer to: Paint Defects and Damage (501-36 Paint General Information, General Procedures).

Battery Acid Damage

Battery acid spray caused by improper handling of flooded batteries.

NOTICE: Batteries contain sulfuric acid. When working near a battery, or if battery acid is present on the vehicle body, protect skin and eyes from contact with the acid. If battery acid contacts the skin or eyes, immediately flush the affected area with water (flush for at least 15 minutes) and seek medical attention without delay. If acid is swallowed, seek medical attention immediately. Failure to follow these instructions may result in injury.

Cause/nature of damage:

• • Etching of the paint layer down to destruction of the paint coating

Repairing the damage:

• Immediately flush acid spray with plenty of water and neutralize it with Motorcraft® Detail Wash.
• If the acid contact time was short, polish the area.

Brake Fluid Paint Damage

Careless handling of brake fluid. The glycols contained in the fluid cause swelling and discoloration.

Cause/nature of damage:

• Temperature and contact time are critical. Spray causes loss of gloss and color lightening.

Repairing the damage:

• Immediately remove the fluid from painted surfaces.
• Then apply a wax and grease remover, following the manufacturer's recommendations.