Paint Damage from Airborne Materials

The following information gives detailed descriptions of paint damage caused by chemical or organic materials. If service is required, identify the source of the damage and follow the recommended service procedure.

Chemical

The effects of chemical airborne materials can be seen as:

• Dark blotches in the paint where the pigment in the paint surface has been attacked.
• Irregular spots that are cracked or etched around the edges and dull in the centers.
• Small orange colored spots caused by iron particles may appear on the paint surface.

Generally, materials that attack a paint film are either acidic or alkaline in nature.

Sulfuric and nitric acids, in general, cause extreme damage to automotive paint finishes. Even very small concentrations of the same materials can cause chemical spotting damage. Due to evaporation and condensation, these acids can create severe etching "spots" that may eventually crack or lift the paint film after some time in service.

Although some automotive finishes are more resistant than others, none are completely immune to these chemicals. The most resistant paints used today are the urethanes because their resin system is least likely to react with chemicals. Air-dry coatings are more susceptible to attack only when they are fresh. The longer the paint dries the more resistant it becomes.

Metallic colors are more intolerant to chemicals because aluminum flake is fairly reactive with either an acid or alkali. The following chart contains the most common acid materials found on automotive finishes. The chart shows a color, the corresponding damage appearance and also the chemical causal agent. It is not applicable for Basecoat/Clearcoat finishes.

CHEMICAL SPOTTING DAMAGE OF AUTOMOTIVE FINISHES

Paint Color	Appearance	Caused
Yellow	White spot Dark brown spot (yellow) Red spot with film degradation Spot blistering	Hydrochloric or muriatic acid Nitric acid Sodium hydroxide (caustic)* Acetic acid
Non-metallic Medium Depth Blue	Whitening Whitening with film degradation Spot blistering	Nitric acid Sodium hydroxide (caustic)* Acetic acid
White	Pink Pink coloration with film degradation Spot blistering Yellowing, non-acrylic lacquer only	Nitric acid Sodium hydroxide (caustic)* Acetic acid Ammonium hydroxide
Medium Depth Blue	Slight light blue spot Dark blue spot Deep purple spot with film degradation Spot blistering	Hydrochloric acid Nitric acid Sodium hydroxide (caustic)* Acetic acid
Pale Blue Metallics	Slight darkening Slight yellowing Severe darkening Severe darkening with film degradation Spot blistering	Hydrochloric acid Ammonium hydroxide Nitric acid Sodium hydroxide (caustic)* Acetic acid
Silver Metallics	Light spot Light spot (enamel turns yellow) Yellowing Dark, film degradation	Hydrochloric acid Ammonium hydroxide Nitric acid Sodium hydroxide (caustic)*

* "Caustic" refers to any alkaline substance that may be "harsh" or "corrosive" depending on strength or concentration.

The following pH chart shows the relationship between acidic and alkaline chemicals and their corresponding pH values. This chart is provided for informational reference only.

ACIDS/ALKALIS AND pH CHART

pH Scale Value	Examples
2.0 - Very Strong Acids	Hydrochloric, Nitric Sulfuric, Phosphoric, Hydrofluoric and Some Wire Wheel Cleaners
3.0 - Strong Acids	Citric, Chromic, Sulfonic, and Human Gastric Juices
4.0 - Acidic	Oxalic, Gluconic, Tartaric Fallout Remover
5.0 - Slightly Acidic	Lactic, Uric, Acid Rain
6.0 - Very Slightly Acidic	Carbonic
7.0 - Neutral	Blood, Most Body Fluids, Distilled Water
8.0 - Very Slightly Alkaline	Urine, Wash Concentrate
9.0 - Slightly Alkaline	Baking Soda
10.0 - Alkaline	Soda Ash, Carb-Kleen
11.0 - Strong Alkaline	Lye, Potash, Tire Cleaner

Organic

Organic damage is generally easier to identify. Organic damage is mostly due to tree sap, bird and insect droppings, dead insects and pollen. Tree sap is easily identified by clear raised drops that may be hard or sticky. Bee or bug dropping spots may appear brownish or yellow in color, about 1/8 to a 1/4 inch in diameter. Dead and decomposing insect bodies are readily visible to the eye. Pollen deposits are small yellow clusters. Each of these items is potentially damaging to any currently available paint system. Other noticeable traits of organic damage are spots that are raised (swelling), micro-crazing (cracked) and pitting due to pollen eating into the paint film. The active ingredients in most organic contaminants are tannic and formic acids. These acids are found in berries and bodily fluids of insects and birds.

Investigations completed at dealerships show that the bright lot lights tend to attract insects. The use of "soft lights" for display and storage lot illumination will help reduce damage resulting from decomposing bugs and droppings by decreasing the number of bugs attracted to these lights. Organic damage is accelerated by heat. During very hot weather conditions, it is important to wash vehicles more often.