What Is Oil Based Paint? Oil based paint was used for centuries, until water based finishes were developed. The oil paint of today is different and safer than the oil paint of yesteryear, and it still has many applications for artists and industrial painters.
This hardy paint has a reputation for resisting harsh conditions and climates.The first paints, used in caves and early structures, were oil-based paints made by adding colored earth or soot to animal fats and using the resulting paste to decorate with. For thousands of years, various oils have been mixed with colorants derived from natural sources to make paint. Early artists from the time of Christ usually made their own paint and often the formulas were guarded secrets. The medium was usually vegetable-based oil. In the 1400s, lead was added to oil paint to enable it to dry faster, and this became an integral part of oil paints for hundreds of years. By 1978, the use of lead was banned in oil paint throughout much of the world including the US because it was toxic, particularly to children. Modern oil paints are quite safe.
Oil paint is any paint that does not use water as a medium. Rather, it contains natural or synthetic resins or oils as a base. Oil paint typically has a stronger odor than water paint. Since it dries by oxidation when exposed to air rather than through evaporation, it can take significantly more time to dry. It is higher in VOCs (Volatile Organic Compounds, the chemical molecules that vaporize as the paint dries) than water paints and may cause mild upper-respiratory distress in some people. Typically it is more durable than water paints. Brushes and equipment must be cleaned with a solvent, like paint thinner or turpentine, since water will not dissolve oil paint.
Oil paints and varnishes are used in boat and shipbuilding because they withstand the elements and salt water. Many artists prefer them over water-based acrylic paints and claim the colors are richer. Oil paints are often used in architectural painting, for cabinets, woodwork and industrial settings. They are also used in Victorian homes for authenticity.
Take more time when using oil paint. It takes longer to dry and is harder to work with. Most synthetic brushes and rollers work fine with oil paints, but natural bristle brushes and lambswool or mohair rollers give a superior finish. Unlike waterpaints, oil paints cannot be touched up later without showing brush and roller marks. Oil paint may, in most cases, be used over water based paints and primers, but water paints should not be used over oil based paints without deglossing or priming the surface.
Oil paint may not be the best choice for all house painting applications, especially on exteriors. It dries to an impermeable film, and is not as flexible as acrylic paints. This means that as surfaces expand and contract due to temperature changes, it is more likely to crack and peel. Modern water paint technology has come a long way in recent decades, and for most household uses, it remains the better choice.
Oil paint works well on exterior metal. Oil-based wood stains tend to hold up better than water-based stains for exterior wood, and there is no substitute for oil-based stains for interior wood because they impart a richer, more uniform appearance.
Oil-based primers are the best choice for weathered wood, or cedar and redwood which may stain through water-based primers and paints. It is perfectly acceptable to put water-based acrylic paint over an oil-based primer, although rarely advisable to put water-based paint over an oil based non-primer paint.
