PAINTS AND STAINS - PART TWO
This is part two of a 2 part series of articles on paints and stains.
Problem Solved - Finally, Interior Paints Coatings for Each and 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 would last longer. It could last longer, but as I then found out when I needed to touch up the ceiling only 2 yrs later, exterior paints will discolor on an interior surface. Exterior paints contain special additives made to withstand the outdoors. Interior paints have additives that help the paint dry to a durable, uniform surface finish.
Most of the advances in painting technology have been with latex. Actually, latex has overtaken oil-based paint in a number of areas: toughness and elasticity, as well as ease of application, clean-up, and disposal. Latexes have fewer VOCs than oil-based paints. Some, including the Pristine collection created by Benjamin Moore, are created with no VOCs in any way. Today's latexes are created with top quality pigments and binders that give them more body, so they go on thicker.
Latexes enjoy quite a lttle bit of level of popularity 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 approach is gradually changing as better latexes, including Pratt & Lambert's Accolade Interior Acrylic Semi Gloss, are introduced to the market.
Take The Headache Out of Finding Exterior Paint Coatings
Moisture can be an important concern for exterior paint selection. Every day a family group of four will create several gallons of vaporized water inside a house.
Combined with naturally occurring humidity, this can mean a a large amount of moisture moving through the wall space and siding. Dampness is highest in the baths and kitchen. If these rooms aren't sufficiently ventilated, water will migrate through the surfaces. Vapor barriers help to contain wetness, but vapor always seeks to leave. The structure of a home, the kind of vapor barrier they have, ventilation, and humidity all make selecting the right paint critical.
In wetter climates you require a paint that will let moisture go through the wood, so water doesn't get trapped under the paint and cause blistering and peeling. Latexes are porous and let moisture go through, unlike alkyd paints, which form a waterproof seal. Alkyds also don't flex with areas that expand and shrink, as wood does, especially in colder climates. Latex paints have more elasticity, allowing better adhesion.
I prefer using latex on all exterior surface areas, including wood siding, stucco, and concrete. Latexes withstand fading better than most oil-based paints, and they'll cover either oil-based or latex primer (most oils have to go on top of an alkyd primer).
Latexes do a great job of covering cement. Despite its hardness, cement is very porous, and oil-based paints don't always stick well. For very best durability, I would recommend latex enamel.
In general, if I know of a latex product that provides superior performance, I will choose it over an oil-based product that has to be cleaned with a thinner.
Latex only requires water. Thinners add yet another cost, are hard to dispose of, and usually end up spattered on my skin or clothes, no matter how careful I am.
Take The Headache Out of Using Stains
You could spend a life learning about stains and sealers, but there's nothing mysterious about them. The bottom line in determining which stain to work with is to familiarize yourself 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.
Outside stains come in oil based, varnish, polyurethane, and water-borne solvents. Stains have less colorant than paint and more solvents, giving them greater wood penetration. Waterproofing is important with exterior stains. Most include built-in sealants to increase toughness and help maintain the wood. The colouring 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 definitely used along with 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, that are better to apply, combine, 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 provides what you want in one coating (make sure to use a conditioner on porous wood, such as pine and birch wood, to avoid splotching). Dyed stains are extremely difficult to touch up. Every coating eventually will need touching up, so make certain 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 want to avoid the watery nature of stains, try a gel stain, which had the majority of the water solvent removed. Gels are simple to use. They spread on, dry out fast, and cover evenly. Because they're colored with pigment, gel stains don't penetrate that well. They're a great choice for porous woods that are hard to cover evenly without a toner. Gel stains do a excellent job of showing off the grain on embossed metal or composite surfaces. I don't recommend using them for hardwoods, which require 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 can 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 prevents them from soaking into the wood pores. Sanding sealer can provide a better adherence for clear coats.
Shellacs tend to be put into sanding sealers to strengthen the resin and provide a quick drying agent. They also add an amber tone, so if you are by using a sanding sealer with shellac, make sure it will not impact the stain. Shellacs have a tendency to yellow aver time and contain toluene, which has a very high VOC content. Shellacs are slowly offering 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 dry alkyd resin sanding sealer without shellac known as Rez 77-1. This specific 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 shouldn't be used under a water based polyurethane.
Oil-based sanding sealers can also be used to seal outside wood, especially decking, which is constantly exposed to sun and water. For color uniformity in areas like decks, you need to completely coat, or back prime, the lumber before it is in place, using the same sealer or stain. Olympic Water Guard, Messmer's UV Plus, Behr's, & most high end deck stains are excellent water repellent sealers that can also be utilized for priming exterior wood.
Wood and Stain Sealers for Interior Wood – Safely
Sealers, including varnishes, lacquers, urethanes, and shellacs, are added to 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 buy stain/sealer combinations, they have a tendency to yellow, are difficult to maintain, and don't endure as long as separately applied stain and sealers.
Varnishes contain oils such as Tung oil, a very hard, durable sealant that can be brushed on and dries slowly. Varnishes are easy to clean and maintain with soap and water accompanied by a wiped on varnish, which often keeps a wood surface looking ideal for years. Make sure there's no wax in your cleaner, because wax clogs wood pores. I favor using Hope's Tung Oil varnish for a wipe-on maintenance coat. Lacquer is a fast dry sealer that more often than not must be sprayed, since it becomes tacky almost immediately.
Polyurethanes do almost everything shellac does, but they're easier to maintain. While shellacs act like paint, polyurethanes act more like a clear coating that permeates the wood instead of sitting on top of it. Polyurethanes brush on and dry out quickly, with little smell and VOCs. They have more or less replaced shellacs as a clear sealer. Another reason urethanes have become such popular sealers is the fact they don't require sanding sealers.
The odors associated with many paints and stains can be more than simply offensive, they can be toxic. Solvent based varnishes, lacquers, and shellacs provide a ultra hard coating but contain high VOC levels. Water based 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 sufficient VOCs to warrant a respirator.
Although they resist yellowing, water borne sealers such as acrylic latex polyurethanes do have a tendency to raise the grain. They will also set up or "flash off" quickly at temps higher than 60°F. The very best working temperature for most water borne 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 complete the drying out process. A contractor I knew once used water borne latex polyurethane sealer that flashed off so fast he could only apply it between 5 A.M. and 9 A.M. Anything later than that was too warm.
Minwax makes very good water borne polyurethane, as do Pittsburgh, Pratt & Lambert, Benjamin Moore, and others.
Improved Exterior Stains and Sealers
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 get 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 and is also 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 outside stain, which make them stronger. I would recommend buying a high-end stain that is semi-transparent or what's called a trans-oxide. Until just lately, the major problem with outside stains was their low UV resistance, but newer trans-oxides have finely ground metal mixed in for greater protection. A high end deck stain won't need a separate sealer coating, although you can add one (such as Olympic Water Guard) if you think extra protection is needed to combat moisture content and sun exposure. Better deck stains retail for approximately $35 a gallon and cover 300 to 400 sq. ft.
Avoid using deck stains which contain silicone. Despite their attractive price, they are not a good deal. Advertisements for silicone stains and deck sealers often show beaded up water on the deck, and many people are fooled into thinking that this is the indication of an effective coating. However, silicon deteriorates quickly, usually in a matter of months, leaving a discolored, waxy coat that is clearly a pain to eliminate. The broken down silicone also ceases repelling water.
"High build" coatings such as Sikkens and Messmers work remarkably well on exterior siding, nevertheless they are too soft to be utilized on your deck. Eliminating these coatings requires gallons of wood cleaner and a significant amount of work.
Water borne exterior stains, such as Sherwin Williams Woodscapes, incorporate the features of oil-based and latex coatings. They run and drip less than oil based stain, and dry faster, enabling two coatings the same day. Water based stains possess the resilience and flexibility of the latex stain, giving them lasting strength. They're a good choice for most applications. But bear in mind that cleaning up water borne stains can take work. There are a couple of oil components in the solvent which 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, please ask people in the know. A skilled, knowledgeable salesperson can answer any questions you might have. Look for a paint store with personnel having at least 10 years of experience in the business. Inquire further what has worked best for your unique application and ask to read a spec sheet on the product in question.
The answers you get will rely upon whom you ask. A paint store will try to sell you one of their products, after all, that is why they're in business. Painting contractors might not be impartial, either. They have to sell their expertise. I get plenty of phone calls from people desiring assistance with their painting problems. Most painters, including myself, don't mind giving one hour of our time, but if you want comprehensive answers, consider finding a contractor for a professional analysis. Rates vary, but I usually charge about $60 for a written and oral evaluation, depending on driving time included. A paid examination will let you know whether you should paint, stain, or re-side, as well as which coating 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
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