FEATURES OF STAINS AND PAINTS
Nearly every kind of surface, from drywall to concrete, needs protection from the elements. These hazardous elements can range from 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 property is usually about one tenth the thickness of your skin, and interior paint is even thinner. We ask a lot of that covering of skin. What it can do is determined by a variety of factors, like the quality and brand 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 can go on with little spattering. An excellent interior stain or clear coat should resist fading, peeling, or yellowing, and also be easy to keep, free of impurities or waxes which could collect dirt and make cleaning or recoating difficult. External paints should dry with a toughness that resists deterioration from all sorts 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 outdoor surfaces should give a similar high performance.
Historical Development of Paint and Stain
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 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 house, on the other hand, is subjected to all types 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 vegetable dyes to paint images which may have lasted a large number 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 to preserve wood. The Chinese used gums and resins to make advanced varnishes such as, shellac, turpentine, copal, and mastic. The formulas and applications for those varnishes also evolved little over the centuries.
Milk paint dates 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 should be covered with a wax or varnish, which is very durable.
Created from hogs' bristles, badger and goat hair, brushes also changed 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 pasture dirt and grime. Most mineral or inorganic pigments originated from rust, potassium, sea salt, sulphur, alum (aluminum), and gypsum, among others. Some extravagant works incorporated valuable stones such as lapis lazuli. Hundreds of organic pigments from plants, insects, and animals made up 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 released in 1773 was reprinted 14 times until 1900, with only small 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 during 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 dangerous. Paints and varnishes were usually combined on site, where a ground pigment was mixed with lead, oil, and solvents over sustained high temperature. The maladies that arose from toxic exposure were common among painters at least before late 1800s, when paint companies started out to batch ready mix coatings. While exposure to 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 replacement for the natural pigments and dyes that came from Germany. They started out 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 popularity 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 each year 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 early 1990s with the introduction of a fresh category of paints and stains known as "water borne." Created by the necessity to adhere to stricter regulations, water borne coatings decrease the volatile organic materials, or VOCs, within standard paint and stains. Toxic and flammable, VOCs evaporate as a coating's solvent dries. They can be inhaled or absorbed 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 are the vehicle or medium, for the substances in a paint or stain. They determine how fast a covering dries and 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 longevity. The cost of paint will depend on in large part upon the grade of its binder.
Because water is the vehicle in latex paint, it dries quickly, allowing for 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 include a higher amount of acrylic resins for better hardness and durability.
Alkyds and oil-based paints are simply the same thing. The word alkyd is derived from "alcid," a combination 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 commercial use and a urethane revised 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 swell wood grain and require sanding between coats.
Paint and Stain 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 a similar color with as few coats as is feasible. Titanium dioxide is the primary the 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; Paint and Stain
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 streaks have a chance 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 time. 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 triggered when the soap wetting agent rises to the top as it dries. The better the paint, the less pin holing you should 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. It is no longer the truth with better paints, which can be opened and used right out of the shaker with no danger 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 temperatures from 50°F to 120°F. With added coalescents and, contrary to popular belief, antifreeze, some latexes can be employed in the same temperatures range, and even lower. Some outdoor latexes can be securely applied at conditions 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 deterioration. 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. UV blockers in paint may consist of finely ground metals and ground glass which is currently being added for even greater reflection of natural sunlight.
If you reside in a region with lots 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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