THE FUNCTION OF STAINS AND PAINTS
Nearly every kind of surface, from drywall to concrete, needs protection from the elements. These harmful elements can range from raging blizzards to innocent looking sunlight on a dining room wall. The full total thickness of the paint that ends up outside of your residence is usually about one tenth the thickness of your own skin, and interior paint is even thinner. We ask a whole lot of that covering of skin. What it can do depends upon a variety of factors, like the quality and brand of paint or stain, and how well the walls 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 coating should resist fading, peeling, or yellowing, and also be easy to maintain, free of impurities or waxes which could collect dirty residue 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 surfaces. With their thorough penetration and resistance to ultraviolet (UV) light, the stains and finishes on your home's outside surfaces should give a similar high performance.
The Evolution 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 may have been honey, starch, or gum. You may be wondering why these cave paintings have lasted a large number of years while the paint on the south part of your property is peeling after only three winters. Here's why: The continuous mild temperature, humidity, and dark interiors of caves are ideal preservatives. Your house, on the other hand, is exposed to all sorts 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 heated and mixed with Earth and flower dyes to paint images which have lasted thousands of years. The Egyptians used asphalt and pitch to preserve their paintings. The Romans later used white lead pigment, creating a formula that could exist almost unchanged until 1950.
The Chinese used oil from the Tung tree to cement the Great Wall, and 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 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 smooth and hard, and can be tinted with other pigments. Like stains, milk paint should be sealed with a wax or varnish, and is also very durable.
Created from hogs' bristles, badger and goat hair, brushes also improved 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, 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 came from rust, potassium, sea salt, sulphur, alum (aluminum), and gypsum, along with others. Some extravagant works incorporated treasured stones such as lapis lazuli. A huge selection of organic and natural pigments from plants, insects, and animals composed the rest of the 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 modest revisions. However, the colder climates of northern Europe did bring about the need for more durable paint, and in the 1500s the Dutch designer Jan van Eyck developed oil-based paint.
Starting in 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, in which a ground pigment was blended with lead, oil, and solvents over sustained high heat. The maladies that arose from poisonous exposure were common amongst painters at least before late 1800s, when paint companies started to batch ready mixed coatings. While contact with contaminants given off during the mixing process subsided, contact with the harmful ingredients 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 discover 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.
Inventions in the painting industry have extended well beyond pigments. Water-based latexes have gained in acceptance 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 yearly with significant 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 necessity to comply with stricter regulations, water borne coatings reduce the volatile organic substances, or VOCs, within standard paint and stains. Dangerous and flammable, VOCs evaporate as a coating's solvent dries. They can be inhaled or soaked up through the skin, and create ozone pollution when subjected to sunlight.
THE CHEMISTRY OF STAINS AND PAINTS Paints and stains contain four basic types of ingredients: solvents, binders, pigments, and additives.
Solvents and Binders
Solvents will be the vehicle or medium, for the substances in a paint or stain. They regulate how fast a finish dries and 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 durability. 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 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 higher hardness and durability.
Alkyds and oil-based paints are basically the same thing. The term alkyd comes 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 industrial use and a urethane customized 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 raise hardwood grain and require sanding between coats.
Pigments; Paint and Stain
Pigments will be the costliest element in paint. In addition to providing color, pigments also have an effect on paint's hiding power - its capability to cover an identical color with as few coats as it can be. Titanium dioxide is the primary 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 easier.
Additives
Additives determine how well a paint contacts, or wets, the surface area. In addition they 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 potential to flow and level; they go on smoother than latex and dry more slowly, so brush stridations have more time to level out. That's why oil-based paints tend 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 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 top 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 couple of hours. That is definitely no longer the case with better paints, which can be opened up and used right out of the shaker with no threat of pin holing.
Coalescents help latex resins bond, especially in colder weather. Oil-based paint, since it dries slowly and resists freezing, can stick and dry in temps from 50°F to 120°F. With added coalescents and, believe it or not, antifreeze, some latexes can be applied in the same heat range, and even lower. Some outside latexes can be securely applied at temperature 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 temperatures. As the wetting agents have been removed, the latex dries faster.
UV blocking chemicals have been added to paints and stains to help slow deterioration. Sunlight is responsible for much of the break down of any covering. It fades colors, dries paint, and adds to the expansion and contraction process which makes paint crack and peel off. UV blockers in paint may contain finely ground metals and ground glass which is currently being added for even greater reflection of the sun's rays.
If you stay in an area with tons of humidity, rainwater, 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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