FEATURES OF PAINTS AND STAINS - PART II
This is part two of a 2 part series of articles on paints and stains.
Finally, 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 last longer, but as I then found out when I needed to touch up the ceiling only two years later, exterior paints will discolor on an interior surface. Exterior paints contain special additives designed to withstand the outdoors. Interior paints have additives that help the paint dry 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 several areas: toughness and elasticity, as well as ease of use, clean-up, and disposal. Latexes have fewer VOCs than oil-based paints. Some, like the Pristine lines made by Benjamin Moore, are created with no VOCs at all. Today's latexes are made with higher quality pigments and binders that give them more body, so they go on thicker.
Latexes enjoy quite a bit of level of popularity for interior applications, specifically for walls and ceilings. Alkyds continue to be the professionals' choice for trimming work because oil based paints are better 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, are introduced to the market.
Take The Headache Out of Finding Exterior Paint Coatings
Moisture can be an important consideration for exterior paint selection. Every day a family group of four will generate 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 surfaces and siding. Water is highest in the baths and kitchen. If these rooms aren't sufficiently ventilated, moisture will migrate through the surfaces. Vapor barriers help contain wetness, but vapor always seeks to leave. The structure of a home, the type of vapor barrier it has, ventilation, and dampness all make choosing 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 go through, unlike alkyd paints, which form a waterproof seal. Alkyds also don't flex with surfaces 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 cement. Latexes resist 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 perform a great job of covering cement. Despite its hardness, concrete is very porous, and oil-based paints don't always adhere well. For very best durability, I would recommend latex enamel.
In general, if I know of a latex product that will provide superior performance, I'll choose it over an oil-based product that should be cleaned with a thinner.
Latex only requires water. Thinners add yet another expense, are hard to dispose of, and usually end up spattered on my skin or clothes, regardless of 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 figuring out which stain to use is to familiarize yourself 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 and even more solvents, providing them with increased wood penetration. Waterproofing is important 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 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 usually accompanied by 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, which are simpler to apply, blend, and touch up. Pigmented stains are lighter in color and bring out more of the wood grain. If you are 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 almost impossible to touch up. Every coating eventually will require touching up, so be sure to consider ease of maintenance in your selection of stains. You'll receive 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 had most of the liquid solvent removed. Gels are easy to use. They wipe 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 hard to coat evenly with out 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 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 over stains as sealers. Sanding sealers are different from a sealer like polyurethane, which is not designed to prime. They're similar to varnish, but diluted with solvents to allow better penetration for priming. The hardness of varnishes and lacquers stops them from soaking into the wood pores. Sanding sealer provides a better bond for clear coats.
Shellacs are often put into sanding sealers to strengthen the resin and offer 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 influence the stain. Shellacs have a tendency to yellow aver time and contain toluene, that has a very high VOC content. Shellacs are slowly supplying 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 alkyd resin sanding sealer without shellac named 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 purely for interior wood and must not be used under a water based polyurethane.
Oil-based sanding sealers can also be utilized to seal exterior wood, especially decking, which is continually exposed to sun and water. For color consistency in areas like decks, it's best to completely coat, or back prime, the wood before it goes up, 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.
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 over a stain, or used as a clear coat on unstained wood trim. They could be used for just about 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, 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 followed by a wiped on varnish, which often keeps a wood surface looking great for years. Make certain 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 coat. Lacquer is a quick drying sealer that almost always 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 coat that permeates the wood instead of sitting on it. Polyurethanes brush on and dry quickly, with little odour 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 become more than just offensive, they can be toxic. Solvent based varnishes, lacquers, and shellacs provide a ultra hard covering 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 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 temperature ranges greater 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 out 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 borne polyurethane, as do Pittsburgh, Pratt & Lambert, Benjamin Moore, among others.
Stains and Sealers for the Exterior
Due to 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 similar to 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. 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 usually have more solids than a typical outside stain, which make them more durable. I would recommend buying a high-end stain that is semi-transparent or what is 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 better protection. A high end deck stain won't require a different sealer overcoat, although you can add one (such as Olympic Water Guard) if you think extra protection is needed to fight moisture 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 attractive price, they aren't 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 the indication of an effective coating. However, silicone deteriorates quickly, usually in just a matter of months, producing a discolored, waxy coat that is a pain to remove. The broken down silicone also quits repelling water.
"High build" coatings such as Sikkens and Messmers work remarkably well on exterior siding, nevertheless they are too soft to be used on your deck. Removing 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, enabling two coatings the same day. Water based stains have the resilience and versatility of any latex stain, giving them stamina. They're a great choice for some applications. However that cleaning up water based stains takes work. There are a couple of oil components in the solvent which may have to be cleaned. First use soap and water, then alcohol. Ask your dealer for specific cleaning directions 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, educated salesperson can clear up any questions it's likely you have. Look for a paint store with staff having at least a decade of experience in the business. Ask them 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 running a business. Painting contractors might not be impartial, either. They need to sell their experience. I get lots of calls from people wanting help with their painting problems. Most painters, including myself, don't mind giving an hour of time, but if you need in depth answers, consider finding a contractor for a professional examination. Rates vary, but I charge about $60 for a written and oral examination, with consideration to the traveling time included. A paid analysis will let you know whether you should paint, stain, or re-side, as well as which covering 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
