THE PURPOSE OF STAINS AND PAINTS
Nearly every kind of surface, from drywall to concrete, needs protection from the elements. These dangerous elements can range between raging blizzards to innocent looking sunlight on a living room wall. The total thickness of the paint that ends up outside of your house is usually about one tenth the thickness of your own skin, and interior paint is even thinner. We ask a whole lot of that coating of skin. What it can do depends upon a variety of factors, including the quality and type of paint or stain, and exactly how well the areas are prepared and painted.
Paint and stain should be durable, resisting fading and abrasion and allowing repeated washings. Interior paint should go on with minimal spattering. An excellent interior stain or clear coating should resist fading, peeling, or yellowing, and also be easy to keep, free of impurities or waxes that could collect dirt and make cleaning or recoating difficult. Outside paints should dry with a toughness that resists deterioration from all sorts of exposure, and an elasticity which allows for constantly expanding and contracting surfaces. With their deep penetration and amount of resistance to ultraviolet (UV) light, the stains and finishes on your home's outdoor surfaces should give a similar high performance.
Historical Development of Paint and Stain
The oldest known paint was used by the painters of Lascaux, who ground natural pigments with water and a binder that may have been honey, starch, or gum. You might be wondering why these cave paintings have lasted a large number of years as the paint on the south part of your property is peeling after only three winters. Here's why: The regular mild temperature, humidity, and dark interiors of caves are ideal chemical preservatives. Your home, on the other hand, is subjected to all sorts of weather and conditions.
The Egyptians knew as early as 1000 B.C. that paint could protect as well as decorate. Beeswax, vegetable oils, and gum arabic were heated and mixed with Earth and herb dyes to paint images that have lasted thousands of years. The Egyptians used asphalt and pitch to protect their paintings. The Romans later used white lead pigment, developing a formula that could exist almost unchanged until 1950.
The Chinese used oil from the Tung tree to cement the Great Wall, and also to preserve wood. The Chinese used gums and resins to make complex varnishes such as, shellac, turpentine, copal, and mastic. The formulas and applications for those varnishes also evolved little in the following centuries.
Milk paint goes back to Egyptian times, was widely used until the late 1800’s when oil-based paints were introduced. Odorless and non-toxic, milk paint today has been revived as an excellent interior paint. Cassein, the protein in milk, dries very flat and hard, and can be tinted with other pigments. Like stains, milk paint must be sealed with a wax or varnish, and is very durable.
Fashioned from hogs' bristles, badger and goat hair, brushes also transformed little for several centuries. Bristles were hand bound, rosined, and greased, then hand laced into the stock of the brush. Hog's hair brushes, called China bristle brushes, remain a preferred brush for oil-based paints.
Pigments originally originated from whatever bore a color, from ground up Egyptian mummies to road dirt and grime. Most mineral or inorganic pigments originated from rust, potassium, sea salt, sulphur, alum (aluminum), and gypsum, along with others. Some extravagant projects incorporated precious stones such as lapis lazuli. Hundreds of organic and natural pigments from plants, insects, and animals made-up all of those other painter's palette.
Paints and stains changed little from the time of the Pharaohs to the Industrial Revolution. A book on varnishes publicized in 1773 was reprinted 14 times until 1900, with only slight revisions. However, the colder climates of northern Europe did bring about the need for more lasting paint, and in the 1500s the Dutch artist Jan van Eyck developed oil-based paint.
Starting around the Middle Ages lead, arsenic, mercury, and different acids were used as binders and color enhancers. These and other metals made the mixing and painting process dangerous. Paints and varnishes were usually mixed on site, where a ground pigment was blended with lead, oil, and solvents over sustained high temperature. The maladies that arose from dangerous exposure were common among painters at least before late 1800s, when paint companies commenced to batch ready mixed coatings. While contact with contaminants given off during the mixing process subsided, exposure to the harmful substances inherent in paints and stains didn't change much before 1960s, when companies ceased making lead based paints.
World War I forced the U.S. painting industry to modernize. Manufacturers had to find a alternative to the natural pigments and dyes that came from Germany. They began to synthesize dyes. Today many pigments and dyes are chemically synthesized.
Enhancements in the painting industry have extended well beyond pigments. Water-based latexes have gained in attractiveness as a safe, quality alternative to oil-based paints. Latexes have changed from simple "whitewashes" to highly advanced coatings that can outlast oil-based products. Both oil-based and latex coatings are emerging yearly with distinctive improvements, including the ground metal or glass that's now added to reflect harming UV light.
A milestone in the evolution of coatings occurred in the early 1990s with the introduction of a new class of paints and stains known as "water borne." Created by the necessity to adhere to stricter regulations, water borne coatings decrease the volatile organic ingredients, or VOCs, within standard paint and stains. Poisonous and flammable, VOCs evaporate as a coating's solvent dries. They could be inhaled or consumed through your skin, and create ozone pollution when subjected to sunlight.
PAINTS AND STAINS... THEIR CHEMISTRY Paints and stains contain four basic types of materials: solvents, binders, pigments, and additives.
Paint and Stain Solvents and Binders
Solvents will be the vehicle or medium, for the materials in a paint or stain. They regulate how fast a covering dries and exactly how it hardens. Water and alcohol are the primary solvents in latex. Oil-based solvents range from mineral spirits (thinner) to alcohols and xylene, to napthas. The solvent also contains binders, which form the "skin" when the paint dries. Binders give paint adhesion and longevity. The expense of paint is based in large part upon the grade of its binder.
Because water is the vehicle in latex paint, it dries quickly, enabling recoating the same day. The odor that you see when utilizing a latex paint or stain is the "flashing," or evaporation, of the binder and solvents. The binders in latex are minute, suspended beads of acrylic or vinyl acrylic that "weld" as the paint dries. Latex enamels contain a better amount of acrylic resins for increased hardness and durability.
Alkyds and oil-based paints are basically the same thing. The word alkyd is derived from "alcid," a combo of alcohol and acid that acts as the drying agent. Both have the same binders, which may include linseed, soy, or Tung oils. Oil based and alkyd enamels may contain polyurethanes and epoxies for extra hardness. Alkyd paints come in powerful combinations such as two part polyester-epoxy for industrial use and a urethane improved alkyd for home use. Urethane boosts resilience.
Water borne coatings use a two part drying system: water is the drying agent, and oils form a hard-drying resin. These new coatings match and sometimes out perform their oil-based cousins. They resist yellowing, are more durable, require only water clean-up, have little odor, and are non-flammable. One disadvantage: They swell wood grain and require sanding between coats.
Stain and Paint Pigments
Pigments will be the costliest element in paint. Besides providing color, pigments also have an effect on paint's hiding power - its capacity to hide a similar color with as few coats as is possible. Titanium dioxide is the primary and most expensive ingredient in pigment. Top quality paints not only have significantly more titanium dioxide, but also more finely ground pigment. Inexpensive paints use coarsely ground pigment, which doesn't bind well and washes off more easily.
Additives; Stain and Paint
Additives determine how well a paint contacts, or wets, the surface. They also help paint flow, level, dry, and resist mildew. Oil is the surfactant, or wetting agent, in oil-based paint. These paints have a natural thickness and capacity to flow and level; they go on smoother than latex and dry more slowly, so brush streaks have more time to level out. That is why oil-based paints tend to drip on vertical areas more than latexes do.
Latex paint has been playing catch up with oil-based paint over the years. Today many latexes outperform oil-based paints and primers, thanks to thickeners, wetting agents (soapy substances that are also known as surfactants), drying inhibitors, defoamers, fungicides, and coalescents. Defoamers keep latex paint from bubbling and leaving pinpricks (called "pin holing") in the paint as it dries. Bubbling is brought on when the soap wetting agent rises to the surface as it dries. The better the paint, the less pin holing you will have. It used to be that if latex paint was shaken at the paint store you had to let it to settle for a few hours. That is definitely no longer the situation with better paints, which is often opened up and used right out of the shaker without threat of pin holing.
Coalescents help latex resins bond, especially in colder weather. Oil-based paint, because it dries slowly and resists freezing, can stick and dry in temperature from 50°F to 120°F. With added coalescents and, contrary to popular belief, antifreeze, some latexes can be applied in the same temperatures range, and even lower. Some outside latexes can be properly applied at temps at only 35°F. Companies including Pratt & Lambert, Pittsburgh Paint, and Sherwin Williams have removed the surfactants to help their latex paints be applied in lower temperatures. Because the wetting agents have been removed, the latex dries faster.
UV blocking additives have been added to paints and stains to help slow the aging process. Sunlight is accountable for much of the breakdown of any covering. It fades colors, dries paint, and adds to the expansion and contraction process that makes paint crack and peel off. UV blockers in paint may consist of finely ground metals and ground glass which is now being added for even more reflection of natural sunlight.
If you stay in an area with plenty of humidity, rainwater, and insects, you may want to consider adding a biocide or fungicide to your paint. Biocide deters insects, and fungicide counters mildew. Many coatings already contain some fungicide, but only in small concentrations because of strict interstate regulations.
Sound Quality Painting
824 90th Dr SE suite B
Lake Stevens WA 98258
(425) 512-7400
OUR EVERETT PAINTING LOCATION WEBSITE
OUR LYNNWOOD PAINTING LOCATION WEBSITE
OUR MARYSVILLE PAINTING LOCATION WEBSITE
OUR EDMONDS PAINTING LOCATION WEBSITE
