THE PURPOSE OF PAINTS AND STAINS - PART II
This is part two of a 2 part series of articles on paints and stains.
Problem Solved - Finally, Interior Paints Coatings for Each 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 last longer, but as I found out when I had to touch up the ceiling only two years later, exterior paints will discolor on an inside 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. In fact, latex has overtaken oil-based paint in a number of areas: durability and elasticity, as well as ease of use, clean-up, and disposal. Latexes have fewer VOCs than oil-based paints. Some, including the Pristine line made by Benjamin Moore, are created without VOCs at all. Today's latexes are made with top quality pigments and binders that give them more body, so they go on thicker.
Latexes enjoy quite a lttle bit of reputation for interior applications, specifically for walls and ceilings. Alkyds remain the professionals' choice for trimming work because oil based paints are simpler to paint on detailed surfaces like molding and trim. However, that traditional approach is slowly 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 is an important consideration for exterior paint selection. Each day a family group of four will create several gallons of vaporized water in the house.
Coupled with naturally occurring humidity, this may mean a lot 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 walls. Vapor barriers help to contain wetness, but vapor always seeks to leave. The structure of a home, the type of vapor barrier they have, ventilation, and dampness all make choosing the right paint critical.
In wetter climates you need 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 water go through, unlike alkyd paints, which form a waterproof seal. Alkyds also don't flex with floors that expand and contract, as wood does, especially in colder climates. Latex paints have more elasticity, allowing better adhesion.
I favor using latex on all exterior surfaces, including wood siding, stucco, and concrete. Latexes avoid fading 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 cement. Despite its hardness, cement is very porous, and oil-based paints don't always stay well. For greatest durability, I recommend latex enamel.
In general, if I know of a latex product that provides superior performance, I'll choose it over an oil-based product that has to be cleaned with a thinner.
Latex only requires water. Thinners add one more expenditure, are hard to dispose of, and usually end up spattered on my skin or clothes, regardless of how careful I am.
Improve Your Interior Staining
You can spend a life time learning about stains and sealers, but there is nothing mysterious about them. The bottom line in determining which stain to make use of is to become acquainted with the product lines available. Scan 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 plus more solvents, giving them increased wood penetration. Waterproofing is important with exterior stains. Most come with built-in sealants to increase sturdiness and help protect 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 covering. Pigment is a finely ground coloring that doesn't penetrate the grain as deeply as a dye. That's why a pigmented stain is often 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 better to apply, combine, and touch up. Pigmented stains are lighter in color and draw out more of the wood grain. If you are looking for darker results, a dyed stain will provide 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 choice 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 avoid the watery nature of stains, get a gel stain, which had most of the water solvent removed. Gels are easy to use. They spread on, dry out 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 tough to coat 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 using them for hardwoods, which need a good dye stain to emphasize the depth and beauty of the grain.
No-Fuss Painting Using Sanding Sealers
Sanding sealers are interior primers that both penetrate and seal wood. You can use them under clear coats or over stains as sealers. Sanding sealers are different from a sealer like polyurethane, which is not made to prime. They're more like varnish, but diluted with solvents to permit better penetration for priming. The hardness of varnishes and lacquers stops them from soaking in to the wood pores. Sanding sealer can provide a better adherence for clear coats.
Shellacs are often put into sanding sealers to fortify the resin and offer a quick drying agent. In addition they add an amber tone, so if you are using a sanding sealer with shellac, make sure it won't have an effect on the stain. Shellacs have a tendency to yellow aver time and contain toluene, that has a high VOC content. Shellacs are slowly giving ways to new sanding sealer formulas with lower VOCs and better performance.
Alkyd resin sanding sealers likewise have high VOCs, although less than their shellac based cousins. Pittsburgh Paints makes a slow dry alkyd resin sanding sealer without shellac named Rez 77-1. This particular primer/sealer is good 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 borne polyurethane.
Oil-based sanding sealers also can be utilized to seal outdoor wood, especially decking, which is constantly subjected to sun and water. For color reliability in areas like decks, you need 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 used for priming outside wood.
Wood and Stain Sealers for Interior Wood
Sealers, including varnishes, lacquers, urethanes, and shellacs, are added to the stain itself, applied as a top coat over a stain, or used as a clear coating on unstained wood trim. They can be used for any type of wood trim, including windows, entry doors, and the casing around them. Although you can buy stain/sealer combinations, they tend 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, an extremely hard, durable sealant that can 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 often keeps a wood surface looking ideal for years. Make sure there is no wax in your cleaner, because wax clogs wood pores. I favor using Hope's Tung Oil varnish for a wipe-on maintenance coating. 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 can do, but they're simpler 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 odour and VOCs. They have more or less replaced shellacs as a clear sealer. Another reason urethanes have grown to be such popular sealers is that they don't require sanding sealers.
The smells associated with many paints and stains can be more than simply offensive, they can be toxic. Solvent based varnishes, lacquers, and shellacs give a super hard finish but contain high VOC levels. Water based sealers, like the stains, match the performance of many solvent based sealers, with fewer VOCs. The VOC content of water based sealers such as Sherwin Williams Kern Aqua Lacquer average about 250 grams per liter, or 2 pounds per gallon, half the usual VOCs of oil-based lacquers. The ethers in water borne 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 tend to raise the grain. They will also set up or "flash off" quickly at temperatures higher than 60°F. The 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 this case, 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 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 borne polyurethane, as do Pittsburgh, Pratt & Lambert, Benjamin Moore, among others.
Stains and Sealers for Exterior Applications
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 which is better to maintain as it ages. However, I favor oil-based products for semi-transparent stains. Added oil solvents let them penetrate deeper. Some of the better stains on the marketplace 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 when compared to a typical outside stain, which will make them more durable. I recommend buying a high-end stain that is semi-transparent or what's called a trans-oxide. Until recently, the significant problem with exterior stains was their low UV resistance, but newer trans-oxides have finely ground metal mixed in for increased 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 believe extra protection is needed to battle moisture content and sun exposure. Better deck stains retail for about $35 a gallon and cover 300 to 400 sq. ft.
Stay away from deck stains that contain silicone. Despite their attractive 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 actually the indication of a successful coating. However, silicon breaks down quickly, usually in a matter of months, leaving a discolored, waxy coat that is clearly a pain to remove. The broken down silicone also stops repelling water.
"High build" coatings such as Sikkens and Messmers work remarkably well on exterior siding, however they are too soft to be utilized on your deck. Eliminating these coatings needs gallons of wood cleaner and way too much work.
Water borne outside stains, such as Sherwin Williams Woodscapes, combine the features of oil-based and latex coatings. They run and drip significantly less than oil based stain, and dry out faster, enabling two coatings the same day. Water borne stains possess the resilience and flexibility of any latex stain, which gives them lasting strength. They're a great choice for most applications. But bear in mind that cleaning up water borne stains requires work. You will find a couple of oil components in the solvent which may have to be cleaned. First use soap and water, then alcohol. Ask your seller for specific cleaning guidelines for water borne stains, and scan the label.
Ask Questions When In Doubt
In the event that you still have questions about which paint or stain to utilize, please ask people in the know. A skilled, proficient salesperson can clear up any questions you might have. Choose a paint store with staff having at least 10 years of experience in the business. Inquire further what has worked best for your particular application and ask to read 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, in the end, that is why they're in business. Painting contractors might not be impartial, either. They need to sell their skills. I get tons of cell phone calls from people hoping for aid with their painting problems. Most painters, including myself, don't object to giving an hour of our time, but if you want in depth answers, consider finding a contractor for a professional evaluation. Rates vary, but I charge about $60 for a written and oral examination, with consideration to the driving time involved. A paid analysis will let you know whether you should paint, stain, or re-side, as well as which coating might be best for your project. Each painting job has unique conditions that require specific answers.
Sound Quality Painting
824 90th Dr SE suite B
Lake Stevens WA 98258
(425) 512-7400
