FEATURES OF STAINS AND PAINTS
Nearly 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 total thickness of the paint that 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 coating of skin. What it can do depends on a number of factors, including the quality and kind 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 can go on with minimal spattering. An excellent interior stain or clear finish should resist fading, peeling, or yellowing, and also be easy to maintain, free from impurities or waxes that 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 level of resistance to ultraviolet (UV) light, the stains and finishes on your home's external surfaces should provide a similar high performance.
Historical Development 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 while the paint on the south part 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 house, on the other hand, is subjected to all varieties 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 seed dyes to paint images which may have lasted a large number of years. The Egyptians used asphalt and pitch to preserve their paintings. The Romans later used white lead pigment, developing 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 evolved little in the following 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 even and hard, and can be tinted with other pigments. Like stains, milk paint should be sealed with a wax or varnish, and it is very durable.
Fashioned from hogs' bristles, badger and goat hair, brushes also changed little for several 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 came from anything that bore a color, from ground up Egyptian mummies to pasture dirt. Most mineral or inorganic pigments came from rust, potassium, sea salt, sulphur, alum (aluminum), and gypsum, among others. Some extravagant works incorporated treasured stones such as lapis lazuli. Hundreds of organic 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 shared in 1773 was reprinted 14 times until 1900, with only modest revisions. However, the colder climates of northern Europe have brought 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 blended on site, where a ground pigment was mixed with lead, oil, and solvents over sustained high temperature. The maladies that arose from dangerous exposure were common amongst painters at least before late 1800s, when paint companies began to batch ready mix coatings. While exposure to toxins given off during the mixing process subsided, exposure to the harmful materials 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 find a replacement for the natural pigments and dyes that came 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 altered from simple "whitewashes" to highly advanced coatings that can outlast oil-based products. Both oil-based and latex coatings are emerging each year with notable improvements, like the ground metal or glass that's now added to reflect destroying 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 need to adhere to stricter regulations, water borne coatings reduce the volatile organic chemical substances, or VOCs, within standard paint and stains. Poisonous 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 exposed to sunlight.
PAINTS AND STAINS... THEIR CHEMISTRY Paints and stains contain four basic types of ingredients: solvents, binders, pigments, and additives.
Stain and Paint Solvents and Binders
Solvents are the vehicle or medium, for the elements in a paint or stain. They determine how fast a coating dries and exactly 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 includes binders, which form the "skin" when the paint dries. Binders give paint adhesion and toughness. The expense of paint depends 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 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 greater hardness and durability.
Alkyds and oil-based paints are simply the same thing. The term 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 powerful combinations such as two part polyester-epoxy for professional 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 more durable, require only water clean-up, have little odor, and are non-flammable. One disadvantage: They raise lumber grain and require sanding between coats.
Pigments; Stain and Paint
Pigments are the costliest ingredient in paint. In addition to providing color, pigments also affect paint's hiding power - its ability to cover an identical color with as few coats as possible. 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 more easily.
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 capability to flow and level; they go on smoother than latex and dry more slowly, so brush stridations have more time to level out. That is why oil-based paints have a tendency to drip on vertical surfaces 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, 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 let it to settle for a few hours. This is no longer the truth with better paints, which may be opened up and used right out of the shaker without 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 conditions from 50°F to 120°F. With added coalescents and, contrary to popular belief, antifreeze, some latexes can be employed in the same heat range, and even lower. Some outside 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 temperature. As the wetting agents have been removed, the latex dries faster.
UV blocking chemicals have been put into paints and stains to help slow deterioration. Sunlight is responsible for much of the breakdown 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 greater reflection of natural sunlight.
If you stay in a region with lots 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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