combination (solvent, binder, and pigment) is considered to be a vehicle. The term vehicle comes from
the ability to transport and apply the liquid to the surface being coated. Once on the surface, the solvent
evaporates and the vehicle becomes a pigment-binder system. Paint application properties (such as
spreadability) are usually characterized by the vehicle in its liquid condition. The viscosity, rate of
solvent evaporation, and consistency of the wet coating are most important during application. After
application, the pigments determine the corrosion-inhibitive properties and, generally, the color and
some flow-control properties of the applied coating. The binder determines the weatherability of the
coating, its environmental resistance, and its ability to function in a given environment. The required
surface preparation, and often the application equipment and techniques, are determined by the binder.
2-3. Purpose and Function of Protective-Coating Materials. The military uses paint to
camouflage weapons and installations and, recently, for identification purposes. The use of and demand
for protective coatings have grown until, today, over 5 billion dollars each year is spent on them. The
military, along with other government agencies and commercial establishments, uses a considerable
quantity of these coatings for protection, sanitation, cleanliness, illumination, visibility, safety,
efficiency, appearance, camouflage, and fire retardance.
a. Protection. Protection of the surface is the most important purpose for paint. If properly
chosen and applied, your painting efforts will protect wood buildings from moisture and sunlight, metal
structures from corrosion, and concrete and masonry surfaces from the weather. Paint, when regularly
programmed, offers long-range protection that extends the useful life of a structure.
b. Sanitation and Cleanliness. The use of paint and proper painting operations will promote
sanitation and cleanliness. Paint provides smooth, nonabsorptive surfaces that are easily washed and
kept fee of dirt. Such surfaces tend to keep foodstuffs from adhering. Adhering foodstuff harbors germs
and causes disease. The coating of rough or porous areas seals out dust and grease that would otherwise
be difficult to remove. Paint coatings will reveal buildup of foreign substances, indicating that better
housekeeping practices are in order. Paint coating, therefore, is an essential part of general maintenance
programs that is performed for hospitals, mess halls, offices, warehouses, and living quarters.
c. Illumination and Visibility. When white or light-tinted paints are applied to ceilings and
walls, they reflect both natural and artificial light, help brighten rooms, and increase visibility. On the
other hand, darker colors reduce the amount of reflected light. Flat paints diffuse, soften, and evenly
distribute illumination; whereas gloss finishes reflect more like mirrors and may create glare. Color
contrasts improve visibility of the painted surface, especially when paint is applied in distinctive
patterns. For example, white on black, white on orange, or yellow on black can be seen at greater
distances than single colors or other combinations of colors.
d. Safety and Efficiency. A recent innovation is to use paint for the identification of pipes
carrying different material, such as oil, steam, water, and air, through a hangar or an industrial plant.
Paint is also used to indicate hazards or danger areas by using various