FEATURES OF PAINTS AND STAINS
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PAINTS AND STAINS
Almost 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 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 great deal of that layer of skin. What it can do depends on a variety of factors, like the quality and brand of paint or stain, and exactly how well the surfaces are prepared and painted.
Paint and stain should be durable, resisting fading and abrasion and allowing repeated washings. Interior paint can go on with minimal spattering. A quality 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 grime 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 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 exterior should give a similar high performance.
A Timeline of Stain and Paint
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 may be wondering why these cave paintings have lasted thousands of years as the paint on the south part of your home is peeling after only three winters. Here's why: The constant mild temperature, humidity, and dark interiors of caves are ideal chemical preservatives. Your house, on the other hand, is exposed to all kinds 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 warmed and blended with Earth and plant dyes to paint images which may 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 would 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 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 dates back to Egyptian times, was widely used up 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 must be covered with a wax or varnish, and is very durable.
Fashioned 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 came from anything that bore a color, from ground up Egyptian mummies to pasture 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 valuable stones such as lapis lazuli. Hundreds of organic and natural pigments from plants, insects, and animals comprised 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 published 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 durable paint, and in the 1500s the Dutch artist 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 combined on site, in which a ground pigment was blended with lead, oil, and solvents over sustained high temperature. 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 toxins given off through the mixing process subsided, exposure to the harmful materials 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 started out 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 notable 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 very early 1990s with the introduction of a new category of paints and stains known as "water borne." Created by the need to comply with stricter regulations, water borne coatings reduce the volatile organic compounds, or VOCs, within standard paint and stains. Dangerous and flammable, VOCs evaporate as a coating's solvent dries. They could be inhaled or absorbed through the skin, and create ozone pollution when subjected to sunlight.
STAINS AND PAINTS... THEIR CHEMISTRY
Paints and stains contain four basic types of ingredients: solvents, binders, pigments, and additives.
Paint and Stain Binders and Solvents
Solvents will be the vehicle or medium, for the materials in a paint or stain. They regulate how fast a finish dries and exactly how it hardens. Water and alcohol are the main solvents in latex. Oil-based solvents range between 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 durability. The expense of paint will depend on in large part upon the quality of its binder.
Because water is the vehicle in latex paint, it dries quickly, allowing for 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 include a higher amount of acrylic resins for higher hardness and durability.
Alkyds and oil-based paints are simply the same thing. The word alkyd comes 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 professional use and a urethane improved alkyd for home use. Urethane boosts durability.
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 solid wood grain and require sanding between coats.
Pigments
Pigments are the costliest component in paint. Besides providing color, pigments also affect paint's hiding power - its potential to protect a similar color with as few coats as you can. Titanium dioxide is the principal 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 easier.
Additives; Paint and Stain
Additives regulate 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 potential to flow and level; they go on smoother than latex and dry more slowly, so brush stridations have more time to smooth out. That's why oil-based paints tend to drip on vertical surfaces 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, thanks to 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 had to allow it to settle for a couple of hours. This really is no longer the truth with better paints, which is often opened 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 temperatures from 50°F to 120°F. With added coalescents and, contrary to popular belief, antifreeze, some latexes can be employed in the same temperature range, and even lower. Some outdoor latexes can be securely applied at temperatures 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 temperature. Because the wetting agents have been removed, the latex dries faster.
UV blocking additives have been added to paints and stains to help slow deterioration. 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 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 the sun's rays.
If you live 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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