MORE ABOUT STAINS AND PAINTS - PART TWO
This is part 2 of a 2 part series of articles on paints and stains.
Take The Headache Out of Finding Interior Paints Coatings for Each 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 may 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 interior surface. Exterior paints contain special additives made to withstand the outside. 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: strength and elasticity, as well as ease of use, clean-up, and disposal. Latexes have fewer VOCs than oil-based paints. Some, including the Pristine collection made by Benjamin Moore, are created with no VOCs in any way. Today's latexes are created with top quality pigments and binders that provide them more body, so each goes on thicker.
Latexes enjoy quite a lttle bit of attractiveness for interior applications, specifically for walls and ceilings. Alkyds continue to be the professionals' choice for trimming work because oil based paints are easier to paint on detailed surfaces like molding and hardwood 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.
Exterior Paints Coatings for Each Job
Moisture is an important concern for exterior paint selection. Every day a family group of four will generate several gallons of vaporized water inside a 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 surfaces. Vapor barriers help to contain wetness, but vapor always seeks to escape. The structure of a house, the type of vapor barrier it has, ventilation, and moisture all make selecting the right paint critical.
In wetter climates you require 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 dampness pass through, unlike alkyd paints, which form a waterproof seal. Alkyds also don't flex with areas that expand and contract, as wood will, especially in colder climates. Latex paints have significantly more elasticity, allowing better adhesion.
I favor using latex on all exterior surface areas, including wood siding, stucco, and masonry. Latexes resist 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 perform 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 will choose it over an oil-based product that should be cleaned with a thinner.
Latex only needs water. Thinners add one more 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 could spend a life 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 products available. Scan the label, along with any product information you can get, and talk to the personnel 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 a priority with exterior stains. Most include built-in sealants to increase durability 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 covering. 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 much easier 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 provides what you want in one coat (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 require touching up, so make certain to consider ease of maintenance in your selection 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 has had almost all 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 troublesome to cover evenly with out a toner. Gel stains do a great job of bringing out the grain on embossed metal or composite surfaces. I don't recommend working with 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 designed to prime. They're more like 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 offer a better bond for clear coats.
Shellacs are often added to sanding sealers to fortify the resin and provide a quick 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 impact on the stain. Shellacs tend to yellow aver time and contain toluene, that has a high VOC content. Shellacs are slowly offering ways to new sanding sealer formulas with lower VOCs and better performance.
Alkyd resin sanding sealers also have high VOCs, although significantly less than their shellac based cousins. Pittsburgh Paints makes a slow drying out alkyd resin sanding sealer without shellac called 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 purely for interior wood and must not be used under a water borne polyurethane.
Oil-based sanding sealers also can be utilized to seal outdoor 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, and most top quality deck stains are excellent water repellent sealers that can also be utilized for priming outdoor wood.
Method for Wood and Stain Sealers on 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 coat on unstained wood trim. They can be used for just about any type of wood trim, including windows, entrance doors, 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 endure as long as separately applied stain and sealers.
Varnishes contain natural oils such as Tung oil, a very hard, durable sealant that can be brushed on and dries slowly. Varnishes are easy to completely 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 is no wax in your cleaner, because wax clogs wood pores. I favor to work with Hope's Tung Oil varnish for a wipe-on maintenance overcoat. Lacquer is a quick dry sealer that almost always must be sprayed, since it becomes tacky almost immediately.
Polyurethanes do almost everything shellac can do, but they're easier 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 smell 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 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 super hard finish but contain very 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 borne 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 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 set up or "flash off" quickly at temps 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 little more slowly. In this case, flashing-off simply means that the solvent evaporates and leaves the resins to finish the drying process. A contractor I know once used water borne 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, and others.
Method for Stains and Sealers on Exteriors
Because of their better penetration and sealing ability, 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 it is better 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 stronger. I recommend buying a high-end stain that is semi-transparent or what's called a trans-oxide. Until lately, 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 different sealer coating, although you can include one (such as Olympic Water Guard) if you believe extra protection is needed to combat dampness and sun exposure. Better deck stains retail for approximately $35 a gallon and cover 300 to 400 sq. ft.
Avoid using deck stains that contain silicone. Despite their low price, they are not a good deal. Advertisements for silicon stains and deck sealers often show beaded up water on the deck, and many people are fooled into thinking that this is actually the indication of a successful coating. However, silicon deteriorates quickly, usually in 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 outside siding, nevertheless they are too soft to be used on your deck. Eliminating these coatings requires gallons of wood cleaner and a significant amount of work.
Water based exterior stains, such as Sherwin Williams Woodscapes, combine the features of oil-based and latex coatings. They run and drip less than oil based stain, and dry faster, allowing for two coatings the same day. Water based stains have the resilience and overall flexibility of any latex stain, giving them stamina. They're a great choice for some applications. But bear in mind that clearing up water based stains needs 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
In the event that you still have questions about which paint or stain to work with, please ask people in the know. A skilled, competent 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 particular application and ask to see 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's why they're in business. Painting contractors may not be impartial, either. They need to sell their experience. I get tons of phone calls from people needing assistance with their painting problems. Most painters, including myself, don't object to giving one hour of time, but if you want in depth answers, consider hiring a contractor for a professional analysis. Rates vary, but I charge about $60 for a written and oral evaluation, depending on the driving time involved. A paid evaluation will tell you 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 require specific answers.
Sound Quality Painting
824 90th Dr SE suite B
Lake Stevens WA 98258
(425) 512-7400
