ILLUMINATION AND VISIBILITYWhite and light-tinted coatings applied to ceilingsand walls reflect both natural and artificial light andhelp brighten rooms and increase visibility. On theother hand, darker colors reduce the amount ofreflected light. Flat coatings diffuse, soften, andevenly distribute illumination, whereas gloss finishesreflect more like mirrors and may create glare. Colorcontrasts improve visibility of the painted surface,especially when paint is applied in distinctive patterns.For example, white on black, white on orange, oryellow on black can be seen at greater distances thansingle colors or other combinations of colors.IDENTIFICATION AND SAFETYCertain colors are used as standard means ofidentifying objects and promoting safety. Forexample, fire protection equipment is painted red.Containers for kerosene, gasoline, solvents, and otherflammable liquids should be painted a brilliant yellowand marked with large black letters to identify theircontents. The colors of signal lights and painted signshelp control traffic safely by providing directions andother travel information.TYPES OF COATINGSLEARNING OBJECTIVE: Upon completingthis section, you should be able to identify thetypes of structural coatings and finishes, andthe general characteristics of each.As a Builder, you must consider many factorswhen selecting a coating for a particular job. Oneimportant factor is the type of coating, which dependson the composition and properties of the ingredients.Paint is composed of various ingredients, such aspigment, nonvolatile vehicle, or binder, and solvent,or thinner. Other coatings may contain only a singleingredient.PAINTIn this section, we’ll cover the basic componentsof paint—pigment, vehicles, and solvents—andexplain the characteristics of different types of paint.CompositionPaint is composed of two basic ingredients:pigment and a vehicle. A thinner may be added tochange the application characteristics of the liquid.PIGMENT.— Pigments are insoluble solids,ground finely enough to remain suspended in thevehicle for a considerable time after thorough stirringor shaking. Opaque pigments give the paint its hiding,or covering, capacity and contribute other properties(white lead, zinc oxide, and titanium dioxide areexamples). Color pigments give the paint its color.These may be inorganic, such as chrome green,chrome yellow, and iron oxide, or organic, such astoluidine red and phthalocyanine blue. Transparent orextender pigments contribute bulk and also control theapplication properties, durability, and resistance toabrasion of the coating. There are other special-purpose pigments, such as those enabling paint toresist heat, control corrosion, or reflect light.VEHICLES, OR BINDERS.— The vehicle, orbinder, of paint is the material holding the pigmenttogether and causing paint to adhere to a surface. Ingeneral, paint durability is determined by theresistance of the binder to the exposure conditions.Linseed oil, once the most common binder, has beenreplaced, mainly by the synthetic alkyd resins. Theseresult from the reaction of glycerol phthalate and anoil and may be made with almost any property desired.Other synthetic resins, used either by themselves ormixed with oil, include phenolic resin, vinyl, epoxy,urethane, polyester, and chlorinated rubber. Each hasits own advantages and disadvantages. When usingthese materials, it is particularly important that youexactly follow the manufacturers’ instructions.SOLVENTS, OR THINNERS.— The onlypurpose of a solvent, or thinner, is to adjust theconsistency of the material so that it can be appliedreadily to the surface. The solvent then evaporates,contributing nothing further to the film. For thisreason, the cheapest suitable solvent should be used.This solvent is likely to be naphtha or mineral spirits.Although turpentine is sometimes used, it contributeslittle that other solvents do not and costs much more.NOTESynthetic resins usually require a specialsolvent. It is important the correct one be used;otherwise, the paint may be spoiled entirely.TypesPaints, by far, comprise the largest family ofstructural coatings you will be using to finishproducts, both interior and exterior. In the following8-2
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