THE FUNCTION OF STAINS AND PAINTS - PART 2
This is part two of a 2 part series of articles on paints and stains.
Take The Headache Out of Finding Interior Paints Coatings for Every Job
Do you ever wonder about the difference between interior and exterior paints? I once used exterior paint on an inside ceiling, reasoning that it could last longer. It could endure longer, but as I then found out when I needed to touch up the ceiling only 2 years later, exterior paints will discolor on an inside surface. Exterior paints contain special additives made to withstand the outside. Interior paints have additives that help the paint dry out to a durable, uniform finish.
A lot of the advances in painting technology have been with latex. In fact, latex has overtaken oil-based paint in several areas: durability and elasticity, as well as ease of application, clean-up, and disposal. Latexes have fewer VOCs than oil-based paints. Some, including the Pristine brand created by Benjamin Moore, are made with no VOCs at all. Today's latexes are created with higher quality pigments and binders that provide them more body, so each goes on thicker.
Latexes enjoy quite a lttle bit of recognition for interior applications, especially for walls and ceilings. Alkyds continue to be the professionals' choice for trim work because oil based paints are much easier to paint on detailed surfaces like molding and trim. However, that traditional school of thought is slowly changing as better latexes, including Pratt & Lambert's Accolade Interior Acrylic Semi Gloss, come on the market.
Exterior Paints Coatings for Each and Every Job
Moisture is an important concern for exterior paint selection. Each day a family of four will generate several gallons of vaporized water in the house.
Combined with naturally occurring humidity, this may mean a lot of moisture moving through the wall surfaces and siding. Water is highest in the baths and kitchen. If these rooms aren't sufficiently ventilated, water will migrate through the walls. Vapor barriers help to contain wetness, but vapor always seeks to leave. The structure of a home, the sort of vapor barrier they have, ventilation, and humidity all make selecting the right paint critical.
In wetter climates you need a paint that will let moisture pass through the wood, so water doesn't get trapped under the paint and cause blistering and peeling. Latexes are porous and let moisture pass through, unlike alkyd paints, which form a waterproof seal. Alkyds also don't flex with floors that expand and shrink, as wood does, especially in colder climates. Latex paints have significantly more elasticity, allowing better adhesion.
I prefer using latex on all exterior surfaces, including wood siding, stucco, and concrete. Latexes resist fading much better than most oil-based paints, and they will cover either oil-based or latex primer (most oils have to go over an alkyd primer).
Latexes do a great job of covering concrete. Despite its hardness, concrete is very porous, and oil-based paints don't always stay well. For greatest durability, I would recommend latex enamel.
In general, if I know of a latex product that will provide superior performance, I will choose it over an oil-based product that must be cleaned with a thinner.
Latex only needs water. Thinners add yet another expenditure, are hard to get rid of, and usually end up spattered on my skin or clothes, no matter how careful I am.
How to Stain Interior Surfaces
You are able to spend a life time studying stains and sealers, but there's nothing mysterious about them. The bottom line in determining which stain to utilize is to become acquainted with the product lines available. Read the label, along with any product information you can get, and speak to the staff at a professional paint shop.
Exterior stains come in oil based, varnish, polyurethane, and water-borne solvents. Stains have less colorant than paint and even more solvents, providing them with higher wood penetration. Waterproofing is important with exterior stains. Most come with built-in sealants to increase sturdiness and help maintain the wood. The color in stains can be pigments, dyes, or both. A semi-transparent stain has more dye for grain penetration. A solid stain has more pigment for surface coating. Pigment is a finely ground coloring that doesn't penetrate the grain as deeply as a dye. That's why a pigmented stain is usually accompanied by a sealer such as urethane or varnish.
Some high quality interior stains have dyes to penetrate and pigments to draw out the richness of the grain. Others contain only pigments, which are easier to apply, blend, and touch up. Pigmented stains are lighter in color and bring out more of the wood grain. If you're looking for darker results, a dyed stain will provide what you would like in one layer (be sure to use a conditioner on porous wood, such as pine and birch wood, to avoid splotching). Dyed stains are almost impossible to touch up. Every coating eventually will require touching up, so make sure to consider ease of maintenance in your use of stains. You'll get the best results by using better stains such as Minwax, Pratt & Lambert's Tonetic, Pittsburgh's Rez, or Wood-Kote.
If you wish to stay away from the watery nature of stains, try a gel stain, which has had most of the liquid solvent removed. Gels are easy to use. They spread on, dry fast, and cover evenly. Since they're colored with pigment, gel stains don't penetrate that well. They're a great choice for porous woods that are challenging to cover evenly without a toner. Gel stains do a great job of showing off the grain on embossed metal or composite surfaces. I don't recommend working with them for hardwoods, which need a good dye stain to emphasize the depth and beauty of the grain.
How We Improved Our Painting With Sanding Sealers
Sanding sealers are interior primers that both penetrate and seal wood. You should use them under clear coats or on top of stains as sealers. Sanding sealers are different from a sealer like polyurethane, which is not made to prime. They're similar to varnish, but diluted with solvents to allow better penetration for priming. The hardness of varnishes and lacquers helps prevent them from soaking into the wood pores. Sanding sealer can provide a better adherence for clear coats.
Shellacs are often put into sanding sealers to strengthen the resin and offer an instant drying agent. They also add an amber tone, so if you are utilizing a sanding sealer with shellac, make sure it won't impact the stain. Shellacs tend to yellow aver time and contain toluene, which has a high VOC content. Shellacs are gradually providing ways to new sanding sealer formulas with lower VOCs and better performance.
Alkyd resin sanding sealers likewise have high VOCs, although significantly less than their shellac based cousins. Pittsburgh Paints makes a slow drying out alkyd resin sanding sealer without shellac named Rez 77-1. This particular primer/sealer is wonderful for both interiors and exteriors. Pratt & Lambert's Latex Sanding Sealer has suprisingly low VOCs, but is strictly for interior wood and must not be used under a water borne polyurethane.
Oil-based sanding sealers also can be used to seal outside wood, especially decking, which is constantly exposed to sun and water. For color consistency in areas like decks, it's best to completely coat, or back prime, the lumber before it goes up, using the same sealer or stain. Olympic Water Guard, Messmer's UV Plus, Behr's, and most high end deck stains are great water repellent sealers that also can be utilized for priming outdoor wood.
Wood and Stain Sealers for Interior Wood – Safely
Sealers, including varnishes, lacquers, urethanes, and shellacs, are put into the stain itself, applied as a top coat on top of a stain, or used as a clear coating on unstained wood trim. They can be used for any type of wood trim, including windows, doorways, and the casing around them. Although you can purchase stain/sealer combinations, they have a tendency to yellow, are difficult to keep up, and don't last as long as separately applied stain and sealers.
Varnishes contain oils such as Tung oil, a very hard, durable sealant that may be brushed on and dries slowly. Varnishes are easy to completely clean and keep maintaining with soap and water accompanied by a wiped on varnish, which usually keeps a wood surface looking ideal for years. Make sure there's no wax in your cleaner, because wax clogs wood pores. I prefer making use of Hope's Tung Oil varnish for a wipe-on maintenance coat. Lacquer is a quick dry sealer that more often than not must be sprayed, since it becomes tacky almost immediately.
Polyurethanes do almost anything shellac does, but they're better to maintain. While shellacs act like paint, polyurethanes act more like a clear coating that permeates the wood instead of resting on top of it. Polyurethanes brush on and dry quickly, with little scent and VOCs. They have more or less replaced shellacs as a clear sealer. Another reason urethanes have grown to be such popular sealers is the fact that they don't require sanding sealers.
The smells associated with many paints and stains can become more than just offensive, they can be toxic. Solvent based varnishes, lacquers, and shellacs provide a super hard coating but contain very high VOC levels. Water borne sealers, like the stains, match the performance of several solvent based sealers, with fewer VOCs. The VOC content of water borne sealers such as Sherwin Williams Kern Aqua Lacquer average about 250 grams per liter, or 2 pounds per gallon, half the most common VOCs of oil-based lacquers. The ethers in water based sealers aren't combustible, another advantage, but they still have enough VOCs to warrant a respirator.
Although they resist yellowing, water borne sealers such as acrylic latex polyurethanes do tend to raise the grain. They'll also set up or "flash off" quickly at conditions higher than 60°F. The very best working temperature for most water based acrylic latex polyurethanes is between 50°F and 60°F, which lets them flash a bit more slowly. In cases like this, flashing-off simply means that the solvent evaporates and leaves the resins to finish the drying process. A contractor I know once used water based latex polyurethane sealer that flashed off so fast he could only put it on between 5 A.M. and 9 A.M. Anything later than that was too warm.
Minwax makes very good water based polyurethane, as do Pittsburgh, Pratt & Lambert, Benjamin Moore, among others.
No-Fuss Stains and Sealers for Exteriors
Because of their better penetration and sealing power, most exterior stains sold today are oil-based. However, oil-based solid stains peel off as they grow older, making them more difficult to maintain. A solid stain is like paint: It coats more than it penetrates. A latex solid stain peels less which is much easier to maintain as it ages. However, I prefer oil-based products for semi-transparent stains. Added oil solvents let them penetrate deeper. A number of the better stains on the market include Pittsburgh Solid Color Latex Stain, Messmer's U.V Plus, Moorwood Solid Color Exterior Stain, Sherwin Williams Woodscape stains, Pittsburgh Semi-transparent Exterior Stain, Rez Deck Stain by Pittsburgh, and the Sikkens Cetol system.
Deck stains will often have more solids than a typical exterior stain, which will make them more durable. I would recommend buying a high-end stain that is semi-transparent or what's called a trans-oxide. Until recently, the significant problem with outdoor stains was their low UV resistance, but newer trans-oxides have finely ground metal mixed in for greater protection. A higher end deck stain won't require a separate sealer coating, although you can include one (such as Olympic Water Guard) if you believe extra protection is required to battle moisture and sun exposure. Better deck stains retail for approximately $35 a gallon and cover 300 to 400 sq. ft.
Stay away from deck stains that contain silicone. Despite their low price, they are not a good deal. Advertisements for silicone stains and deck sealers often show beaded up water over a deck, and many people are fooled into thinking that this is the indication of a successful coating. However, silicon deteriorates quickly, usually in just a matter of months, producing a discolored, waxy coat that is a pain to eliminate. The deteriorated silicone also stops repelling water.
"High build" coatings such as Sikkens and Messmers work remarkably well on outside siding, nevertheless they are too soft to be utilized on your deck. Eliminating these coatings calls for gallons of wood cleaner and a significant amount of work.
Water borne exterior stains, such as Sherwin Williams Woodscapes, incorporate the advantages of oil-based and latex coatings. They run and drip significantly less than oil based stain, and dry out faster, allowing for two coatings the same day. Water based stains have the resilience and versatility of a latex stain, giving them stamina. They're a great choice for most applications. However that cleaning up water based stains takes work. You will find a couple of oil components in the solvent that have to be cleaned. First use soap and water, then alcohol. Ask your supplier for specific cleaning directions for water borne stains, and read the label.
When In Doubt, Ask Questions
In the event that you still have questions about which paint or stain to utilize, don't hesitate to ask people in the know. An experienced, competent salesperson can clear up any questions it's likely you have. Choose a paint store with personnel having at least 10 years of experience in the business. Ask them what has worked best for your unique application and ask to see a spec sheet on the merchandise in question.
The answers you get will be based upon whom you ask. A paint store will try to market you one of their products, after all, that's why they're running a business. Painting contractors may not be impartial, either. They have to sell their competence. I get tons of phone calls from people hoping for help with their painting problems. Most painters, including myself, don't object to giving one hour of time, but if you want comprehensive answers, consider hiring a contractor for a professional analysis. Rates vary, but I charge about $60 for a written and oral examination, depending on traveling time involved. A paid analysis will let you know whether you should paint, stain, or re-side, as well as which finish might be best for finishing your project. Each painting job has unique conditions that warrant specific answers.
Sound Quality Painting
824 90th Dr SE suite B
Lake Stevens WA 98258
(425) 512-7400
