WHAT STAINS AND PAINTS DO
Nearly every kind of surface, from drywall to concrete, needs protection from the elements. These damaging elements can range between raging blizzards to innocent looking sunlight on a living room wall. The total thickness of the paint that eventually ends up on the exterior of your home is usually about one tenth the thickness of your skin, and interior paint is even thinner. We ask a great deal of that coating of skin. What it can do depends upon a variety of factors, like the quality and type of paint or stain, and exactly how well the walls prepped and painted.
Paint and stain should be durable, resisting fading and abrasion and allowing repeated washings. Interior paint should go on with little spattering. An excellent interior stain or clear finish 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 types of exposure, and an elasticity that allows for constantly expanding and contracting areas. With their deep penetration and level of resistance to ultraviolet (UV) light, the stains and finishes on your home's external surfaces should give a similar high performance.
Historical Development of Stain and Paint
The oldest known paint was employed by the painters of Lascaux, who ground natural pigments with water and a binder that might have been honey, starch, or gum. You may be wondering why these cave paintings have lasted thousands of years as the paint on the south side of your home 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 a myriad 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 blended with Earth and flower dyes to paint images that 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 sophisticated varnishes such as, shellac, turpentine, copal, and mastic. The formulas and applications for those varnishes also changed 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 has been 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 should be sealed with a wax or varnish, which is very durable.
Created from hogs' bristles, badger and goat hair, brushes also evolved little for many centuries. Bristles were hand bound, rosined, and greased, then hand laced in to the stock of the brush. Hog's hair brushes, called China bristle brushes, are still a preferred brush for oil-based paints.
Pigments originally originated from anything that bore a color, from ground up Egyptian mummies to pasture dirt. Most mineral or inorganic pigments originated from rust, potassium, sea salt, sulphur, alum (aluminum), and gypsum, along with others. Some extravagant projects incorporated treasured stones such as lapis lazuli. A huge selection of organic 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 released in 1773 was reprinted 14 times until 1900, with only modest revisions. However, the colder climates of northern Europe have brought about the necessity for more lasting paint, and in the 1500s the Dutch designer Jan van Eyck developed oil-based paint.
Starting around the Middle Ages lead, arsenic, mercury, and various acids were used as binders and color enhancers. These and other metals made the mixing and painting process hazardous. Paints and varnishes were usually blended on site, in which a ground pigment was mixed with lead, oil, and solvents over sustained high heating. The maladies that arose from harmful exposure were common amongst painters at least before late 1800s, when paint companies started to batch ready mix coatings. While contact with contaminants given off through 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 originated from Germany. They commenced 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 acceptance as a safe, quality alternative to oil-based paints. Latexes have improved from simple "whitewashes" to highly advanced coatings that can outlast oil-based products. Both oil-based and latex coatings are emerging annually 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 very early 1990s with the introduction of a fresh class of paints and stains known as "water borne." Created by the need to comply with stricter regulations, water borne coatings decrease the volatile organic chemical substances, or VOCs, found in standard paint and stains. Dangerous and flammable, VOCs evaporate as a coating's solvent dries. They can be inhaled or assimilated through your skin, and create ozone pollution when subjected to sunlight.
PAINTS AND STAINS CHEMISTRY Paints and stains contain four basic types of substances: solvents, binders, pigments, and additives.
Paint and Stain Binders and Solvents
Solvents are 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 key 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 strength. The cost of paint is dependent 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 notice when 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 contain a higher amount of acrylic resins for greater hardness and durability.
Alkyds and oil-based paints are simply the same thing. The term alkyd is derived from "alcid," a mixture 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 high performance combinations such as two part polyester-epoxy for commercial use and a urethane modified alkyd for home use. Urethane boosts longevity.
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 raise real wood grain and require sanding between coats.
Paint and Stain Pigments
Pigments will be the costliest element in paint. Besides providing color, pigments also impact paint's hiding power - its capacity to hide a similar color with as few coats as you can. Titanium dioxide is the primary the 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.
Stain and Paint Additives
Additives determine how well a paint contacts, or wets, the surface area. 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 capability to flow and level; they go on smoother than latex and dry more slowly, so brush streaks have a chance to level out. That's why oil-based paints tend to drip on vertical areas more than latexes do.
Latex paint has been trying to catch up with oil-based paint over time. 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 let it to settle for a few hours. This is certainly no longer the situation with better paints, which can be opened up and used right out of 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 temps from 50°F to 120°F. With added coalescents and, contrary to popular belief, antifreeze, some latexes can be applied in the same temp range, and even lower. Some exterior latexes can be properly applied at heat at only 35°F. Companies including Pratt & Lambert, Pittsburgh Paint, and Sherwin Williams have removed the surfactants to help their latex paints go on in lower conditions. As 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 a lot of the break down of any covering. It fades colors, dries paint, and increases the expansion and contraction process that makes paint crack and peel. UV blockers in paint may consist of finely ground metals and ground glass which is currently being added for increased reflection of the sun's rays.
If you are 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
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