THE FUNCTION OF STAINS AND PAINTS
Almost 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 dining room wall. The total thickness of the paint that ends up outside of your property is usually about one tenth the thickness of your own skin, and interior paint is even thinner. We ask a whole lot of that coating of skin. What it can do depends on a number of factors, like the quality and kind 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 reduced spattering. An excellent interior stain or clear coat should resist fading, peeling, or yellowing, and also be easy to maintain, free of impurities or waxes that 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 that 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.
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 might have been honey, starch, or gum. You might be wondering why these cave paintings have lasted thousands of years while the paint on the south side of your home is peeling after only three winters. Here's why: The continuous mild temperature, humidity, and dark interiors of caves are ideal preservatives. Your home, on the other hand, is subjected to a myriad 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 warmed and mixed 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, 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 complex varnishes such as, shellac, turpentine, copal, and mastic. The formulas and applications for those varnishes also transformed 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 alternative 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 sealed with a wax or varnish, and is also very durable.
Created from hogs' bristles, badger and goat hair, brushes also transformed 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, are still a preferred brush for oil-based paints.
Pigments originally originated from anything that bore a color, from ground up Egyptian mummies to street dirt. 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 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 printed 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 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 different acids were used as binders and color enhancers. These and other metals made the mixing and painting process dangerous. Paints and varnishes were usually mixed 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 started out to batch ready mixed coatings. While contact with contaminants given off through the mixing process subsided, contact with the harmful substances 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 discover 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.
Inventions in the painting industry have extended well beyond pigments. Water-based latexes have gained in popularity as a safe, quality option 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 yearly with notable improvements, including the ground metal or glass that's now added to reflect damaging UV light.
A milestone in the evolution of coatings occurred in the very early 1990s with the introduction of a new class of paints and stains known as "water borne." Created by the need to adhere to stricter regulations, water borne coatings reduce the volatile organic ingredients, or VOCs, within standard paint and stains. Harmful and flammable, VOCs evaporate as a coating's solvent dries. They can be inhaled or assimilated through the skin, and create ozone pollution when exposed to sunlight.
THE MAKE UP OF PAINT AND STAINS Paints and stains contain four basic types of ingredients: solvents, binders, pigments, and additives.
Paint and Stain Solvents and Binders
Solvents will be the vehicle or medium, for the ingredients 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 contains binders, which form the "skin" when the paint dries. Binders give paint adhesion and toughness. The expense of paint is based 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 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 greater amount of acrylic resins for increased hardness and durability.
Alkyds and oil-based paints are basically the same thing. The word alkyd comes from "alcid," a mixture 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 industrial use and a urethane modified alkyd for home use. Urethane boosts toughness.
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 solid wood grain and require sanding between coats.
Paint and Stain Pigments
Pigments will be the costliest element in paint. In addition to providing color, pigments also have an effect on paint's hiding power - its capacity to hide a similar 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 more easily.
Stain and Paint Additives
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 capacity to flow and level; they go on smoother than latex and dry more slowly, so brush streaks have a chance to smooth out. That's why oil-based paints have a tendency 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, thanks to 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 would have to allow it to settle for a couple of hours. This is no longer the situation with better paints, that 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 conditions from 50°F to 120°F. With added coalescents and, believe it or not, antifreeze, some latexes can be applied in the same temp range, and even lower. Some outside latexes can be properly applied at temperatures as low as 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 responsible for a lot 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. UV blockers in paint may consist of finely ground metals and ground glass which is currently being added for increased reflection of natural sunlight.
If you stay in a region 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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