THE FUNCTION OF STAINS AND PAINTS - PART TWO
This is part 2 of a 2 part series of articles on paints and stains.
Problem Solved - Finally, Interior Paints Coatings for Each and Every Job
Did 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 found out when I had to touch up the ceiling only 2 yrs later, exterior paints will discolor on an inside surface. Exterior paints contain special additives designed 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. Actually, latex has overtaken oil-based paint in a number of 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 collection created by Benjamin Moore, are created with no 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 popularity for interior applications, especially for walls and ceilings. Alkyds remain the professionals' choice for trim work because oil based paints are 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.
Exterior Paints Coatings for Every Job
Moisture is an important concern for exterior paint selection. Each day a family of four will create several gallons of vaporized water inside a house.
Coupled with naturally occurring humidity, this may mean a a large amount of moisture moving through the wall surfaces and siding. Water is highest in the baths and kitchen. If these rooms aren't sufficiently ventilated, moisture will migrate through the walls. Vapor barriers help to contain wetness, but vapor always seeks to escape. The structure of a home, the sort of vapor barrier they have, ventilation, and dampness 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 dampness pass 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 most exterior surfaces, including wood siding, stucco, and cement. Latexes withstand fading better than most oil-based paints, and they'll cover either oil-based or latex primer (most oils have to go over an alkyd primer).
Latexes perform a great job of covering concrete. Despite its hardness, concrete is very porous, and oil-based paints don't always adhere well. For greatest durability, I 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 needs to be cleaned with a thinner.
Latex only needs water. Thinners add one more expense, are hard to dispose of, and usually end up spattered on my skin or clothes, regardless of how careful I am.
Solution For Staining Inside
You could spend a life time studying stains and sealers, but there's nothing mysterious about them. The bottom line in figuring out which stain to utilize is to familiarize yourself with the product lines available. Scan the label, along with any product information you can get, and speak to the personnel 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 higher wood penetration. Waterproofing is a priority with exterior stains. Most come with built-in sealants to increase sturdiness and help maintain the wood. The coloring 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 is why a pigmented stain is often used along with a sealer such as urethane or varnish.
Some high quality interior stains have dyes to penetrate and pigments to bring out the richness of the grain. Others contain only pigments, that are easier to apply, mix, 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 (be 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 require touching up, so make sure to consider the 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 want to avoid the watery nature of stains, get a gel stain, which had almost all of the liquid solvent removed. Gels are easy to use. They wipe on, dry fast, and cover evenly. Since they're colored with pigment, gel stains don't penetrate that well. They're a good choice for porous woods that are tough to coat 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 working with them for hardwoods, which need a good dye stain to emphasize the depth and beauty of the grain.
Amazing Way to Use 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 provides a better adherence for clear coats.
Shellacs are often added to sanding sealers to strengthen the resin and offer an instant drying agent. In addition they add an amber tone, so if you're utilizing a sanding sealer with shellac, make sure it will not have an effect on the stain. Shellacs tend 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 also have high VOCs, although less than their shellac based cousins. Pittsburgh Paints makes a slow drying alkyd resin sanding sealer without shellac called Rez 77-1. This specific primer/sealer is good for both interiors and exteriors. Pratt & Lambert's Latex Sanding Sealer has very 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 utilized to seal exterior wood, especially decking, which is constantly subjected to sun and water. For color uniformity in areas like decks, you need to completely coat, or back prime, the wood before it is in place, using the same sealer or stain. Olympic Water Guard, Messmer's UV Plus, Behr's, and most high end deck stains are excellent water repellent sealers that can also be utilized for priming exterior wood.
No-Fuss Wood and Stain Sealers for Interior Wood
Sealers, including varnishes, lacquers, urethanes, and shellacs, are put into 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 just about any type of 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 clean and keep maintaining with soap and water followed by a wiped on varnish, which usually keeps a wood surface looking ideal for years. Make certain there's no wax in your cleaner, because wax clogs wood pores. I favor utilizing Hope's Tung Oil varnish for a wipe-on maintenance layer. Lacquer is a fast drying sealer that more often than not needs to be sprayed, since it becomes tacky almost immediately.
Polyurethanes do almost everything 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 out 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 they don't require sanding sealers.
The odors associated with many paints and stains can be more than just offensive, they can be toxic. Solvent based varnishes, lacquers, and shellacs provide a very hard coating but contain high VOC levels. Water borne 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 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 have a tendency to raise the grain. They'll also harden or "flash off" quickly at temperature ranges greater than 60°F. The best working temperature for nearly all 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 process. A contractor I knew once used water based latex polyurethane sealer that flashed off so fast he could only use 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.
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 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 favor oil-based products for semi-transparent stains. Added oil solvents let them penetrate deeper. A number 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 than a typical exterior stain, which will make them stronger. I would recommend buying a high-end stain that is semi-transparent or what's called a trans-oxide. Until recently, the major 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 add one (such as Olympic Water Guard) if you think extra protection is needed to fight water 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 low 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, silicone deteriorates quickly, usually in just a matter of months, producing a discolored, waxy coat that is clearly a pain to remove. The deteriorated silicone also quits 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. Stripping these coatings calls for gallons of wood cleaner and a significant amount of work.
Water based 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 based stains possess the resilience and flexibility of a latex stain, which gives them lasting strength. They're a good choice for some applications. But bear in mind that clearing up water based stains takes work. You will discover a couple of oil components in the solvent which have to be cleaned. First use soap and water, then alcohol. Ask your seller for specific cleaning guidelines for water based stains, and read the label.
When In Doubt, Ask Your Painting Professional
In the event that you still have questions about which paint or stain to use, please ask people in the know. A skilled, experienced salesperson can answer any questions it's likely you have. Choose a paint store with personnel having at least a decade of experience in the business. Inquire further 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 rely upon whom you ask. A paint store will attempt to sell you one their own products, after all, that's why they're in business. Painting contractors might not be impartial, either. They have to sell their experience. I get lots of cell phone calls from people needing assistance with their painting problems. Most painters, including myself, don't mind giving an hour of time, but if you need comprehensive answers, consider finding a contractor for a professional analysis. Rates vary, but I charge about $60 for a written and oral analysis, with consideration to the 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 require specific answers.
Sound Quality Painting
824 90th Dr SE suite B
Lake Stevens WA 98258
(425) 512-7400
