FEATURES OF PAINTS AND STAINS
Almost every kind of surface, from drywall to concrete, needs protection from the elements. These hazardous elements can range between raging blizzards to innocent looking sunlight on a dining room wall. The total thickness of the paint that eventually ends up on the exterior of your property is usually about one tenth the thickness of your skin, and interior paint is even thinner. We ask a whole lot of that coating of skin. What it can do depends on a number of factors, including the quality and type of paint or stain, and 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. A quality interior stain or clear coat should resist fading, peeling, or yellowing, and also be easy to keep up, free from impurities or waxes which could collect dirt and make cleaning or recoating difficult. Exterior paints should dry with a toughness that resists deterioration from all types of exposure, and an elasticity which provides for constantly expanding and contracting areas. With their thorough 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 utilized 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 thousands of years as the paint on the south part of your house is peeling after only three winters. Here's why: The frequent mild temperature, humidity, and dark interiors of caves are ideal chemical preservatives. Your home, on the other hand, is subjected to a myriad of weather and conditions.
The Egyptians knew as soon as 1000 B.C. that paint could protect as well as decorate. Beeswax, vegetable oils, and gum arabic were warmed and blended with Earth and vegetable dyes to paint images which have lasted a large number of years. The Egyptians used asphalt and pitch to protect their paintings. The Romans later used white lead pigment, making a formula that would 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 superior varnishes such as, shellac, turpentine, copal, and mastic. The formulas and applications for those varnishes also evolved little during the 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 is being revived as an excellent interior paint. Cassein, the protein in milk, dries very level and hard, and can be tinted with other pigments. Like stains, milk paint needs to be coated with a wax or varnish, which is very durable.
Fashioned from hogs' bristles, badger and goat hair, brushes also evolved 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, are still a preferred brush for oil-based paints.
Pigments originally came from whatever bore a color, from ground up Egyptian mummies to street dirt and grime. Most mineral or inorganic pigments came from rust, potassium, sea salt, sulphur, alum (aluminum), and gypsum, along with others. Some extravagant works incorporated valuable 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 shared in 1773 was reprinted 14 times until 1900, with only modest 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 hazardous. Paints and varnishes were usually mixed on site, where a ground pigment was mixed with lead, oil, and solvents over sustained high heat. The maladies that arose from dangerous exposure were common amongst painters at least before late 1800s, when paint companies began to batch ready mixed coatings. While exposure to toxins given off through the mixing process subsided, exposure to the harmful elements inherent in paints and stains didn't change much until the 1960s, when companies ceased making lead based paints.
World War I forced the U.S. painting industry to modernize. Manufacturers had to discover a replacement for the natural pigments and dyes that originated from Germany. They began to synthesize dyes. Today many pigments and dyes are chemically synthesized.
Innovations in the painting industry have extended well beyond pigments. Water-based latexes have gained in attractiveness as a safe, quality option to oil-based paints. Latexes have evolved from simple "whitewashes" to highly advanced coatings that can outlast oil-based products. Both oil-based and latex coatings are emerging every year with well known improvements, such as 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 category of paints and stains known as "water borne." Created by the necessity to comply with stricter regulations, water borne coatings decrease the volatile organic chemical substances, or VOCs, found in standard paint and stains. Toxic and flammable, VOCs evaporate as a coating's solvent dries. They could be inhaled or absorbed through your skin, and create ozone pollution when subjected to sunlight.
PAINT AND STAINS MAKE UP 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 ingredients in a paint or stain. They regulate how fast a finish dries and exactly how it hardens. Water and alcohol are the key solvents in latex. Oil-based solvents range from mineral spirits (thinner) to alcohols and xylene, to napthas. The solvent also includes binders, which form the "skin" when the paint dries. Binders give paint adhesion and longevity. The cost of paint is based in large part upon the quality 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 by using 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 include a higher amount of acrylic resins for increased hardness and durability.
Alkyds and oil-based paints are basically the same thing. The word alkyd comes from "alcid," a mixture of alcohol and acid that acts as the drying agent. Both have the same binders, which might include linseed, soy, or Tung oils. Oil based and alkyd enamels may contain polyurethanes and epoxies for extra hardness. Alkyd paints come in high performance combinations such as two part polyester-epoxy for professional use and a urethane modified alkyd for home use. Urethane boosts sturdiness.
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 stronger, require only water clean-up, have little odor, and are non-flammable. One disadvantage: They swell lumber grain and require sanding between coats.
Pigments
Pigments will be the costliest component in paint. In addition to providing color, pigments also impact paint's hiding power - its potential to cover an identical color with as few coats as you possibly can. Titanium dioxide is the principal and most expensive ingredient in pigment. Top quality paints not only have 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 ability to flow and level; they go on smoother than latex and dry more slowly, so brush marks have a chance to level out. That's why oil-based paints have a tendency to run on vertical walls 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, because of thickeners, wetting agents (soapy substances that are also called 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 caused 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 would have to allow it to settle for a few hours. This is no longer the truth with better paints, which is often opened up and used right from the shaker without danger of pin holing.
Coalescents help latex resins bond, especially in colder weather. Oil-based paint, because it dries slowly and resists freezing, can adhere and dry in temperature from 50°F to 120°F. With added coalescents and, believe it or not, antifreeze, some latexes can be applied in the same temp range, and even lower. Some outdoor latexes can be safely applied at temps as low as 35°F. Companies including Pratt & Lambert, Pittsburgh Paint, and Sherwin Williams have removed the surfactants to help their latex paints go on in lower heat. 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 responsible for a lot of the break down of any covering. It fades colors, dries paint, and increases the expansion and contraction process which makes paint crack and peel. 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 are in an area with plenty of humidity, rainfall, and insects, you may need 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
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