FEATURES OF STAINS AND PAINTS
Nearly every kind of surface, from drywall to concrete, needs protection from the elements. These dangerous elements can range from raging blizzards to innocent looking sunlight on a bed room wall. The total thickness of the paint that eventually 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 covering of skin. What it can do is determined by a number of factors, including the quality and brand of paint or stain, and how well the walls prepped 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 coating should resist fading, peeling, or yellowing, and also be easy to keep, free from impurities or waxes which 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 that allows 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.
A Timeline of Paint and Stain
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 a large number of years while the paint on the south part of your house is peeling after only three winters. Here's why: The constant mild temperature, humidity, and dark interiors of caves are ideal chemical preservatives. Your home, on the other hand, is subjected 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 seed dyes to paint images which have lasted a large number of years. The Egyptians used asphalt and pitch to maintain 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 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 improved little during the centuries.
Milk paint goes 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 alternative interior paint. Cassein, the protein in milk, dries very smooth and hard, and can be tinted with other pigments. Like stains, milk paint must be coated with a wax or varnish, and 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 road dirt. Most mineral or inorganic pigments came from rust, potassium, sea salt, sulphur, alum (aluminum), and gypsum, amongst others. Some extravagant works incorporated valuable stones such as lapis lazuli. A huge selection 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 published 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 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 blended on site, in which 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 to batch ready mixed coatings. While exposure to poisons 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 discover a replacement for the natural pigments and dyes that originated 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 popularity as a safe, quality option to oil-based paints. Latexes have transformed from simple "whitewashes" to highly advanced coatings that can outlast oil-based products. Both oil-based and latex coatings are emerging yearly with noteworthy 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 early 1990s with the introduction of a new class of paints and stains known as "water borne." Created by the need to comply with stricter regulations, water borne coatings decrease the volatile organic ingredients, or VOCs, within standard paint and stains. Toxic and flammable, VOCs evaporate as a coating's solvent dries. They can be inhaled or assimilated through your skin, and create ozone pollution when subjected to sunlight.
THE CHEMISTRY OF PAINTS AND STAINS Paints and stains contain four basic types of substances: solvents, binders, pigments, and additives.
Paint and Stain Solvents and Binders
Solvents are the vehicle or medium, for the materials in a paint or stain. They determine how fast a finish 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 expense of paint will depend 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 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 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 powerful combinations such as two part polyester-epoxy for professional use and a urethane modified alkyd for home use. Urethane boosts strength.
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 hardwood grain and require sanding between coats.
Stain and Paint Pigments
Pigments will be the costliest component in paint. In addition to providing color, pigments also influence paint's hiding power - its capacity to protect an identical color with as few coats as you can. Titanium dioxide is the primary 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 ability to flow and level; they go on smoother than latex and dry more slowly, so brush streaks have more time to smooth out. That is why oil-based paints tend to run 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, 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 induced 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 couple of hours. This really is no longer the case with better paints, which is often opened and used right from the shaker without threat of pin holing.
Coalescents help latex resins bond, especially in colder weather. Oil-based paint, because it dries slowly and resists freezing, can adhere and dry in temperatures 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 safely applied at temperature ranges at only 35°F. Companies including Pratt & Lambert, Pittsburgh Paint, and Sherwin Williams have removed the surfactants to help their latex paints be applied in lower temperatures. As the wetting agents have been removed, the latex dries faster.
UV blocking additives have been put into paints and stains to help slow the aging process. Sunlight is accountable for a lot 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 contain finely ground metals and ground glass which is now being added for even greater reflection of natural sunlight.
If you reside in a region with a lot of humidity, rainfall, and insects, you may want 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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