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Project Difficulty:
Moderate
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A well-applied stain can draw out the natural character of wood, highlighting the grain and giving it a luster that can turn what might have been an average-looking project into a vibrant work of art. But to get satisfying results like these, you have to do three things right:
1) Choose a stain that is compatible with the wood that you are using and that will create the look you want to achieve.
2) Prepare the wood properly to accept the stain.
3) Apply the stain correctly.
Fortunately, it is easy to perform these steps well once you understand the basics. You need to know the types of stains that are available and when it is best to use each one.
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1.
Types of Stains
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Almost all stains can be put into one of two categories:
Pigmented stains. These stains are made from colored pigments that are suspended in a vehicle, which consists of a base liquid (oil and/or resin solvents of various types) and a binder. The binder consists of ingredients that hold the pigment particles in suspension and affix them to the surface being finished. When you apply a pigmented stain to wood, the pigments lodge in the wood’s pores and lie on the surface of the wood, rather than actually changing the color of the wood’s fibers. Depending upon whether they are semi-transparent or solid color stains, pigmented stains will allow the grain and texture of the wood to show through in varying degrees. Also, you have to stir pigmented stains constantly to keep the pigment suspended in the liquid. These stains are usually applied with a brush, although you may wipe them onto the surface with a lint-free cloth.
Dye stains. Dye stains are soluble in water, alcohol, and other types of solvents. Because they dissolve in the base liquid, these colored stains can penetrate deeply into the wood, coloring the fibers in much the same way that clothing dyes color the fiber of cotton. Dye stains may be applied with a brush, cloth, or paint sprayer, and you can get quite a variety of effects, depending on how thickly the stain is applied or the extent to which it is wiped off with a soft, lint-free cloth (Fig. 1). The drawback to dye systems is that they have a tendency toward fading and bleeding.
The above categories of stain can be further divided into the following subcategories:
Non-grain-raising stains (NGR). These are a type of dye stain mixed with a fast-drying coating such as lacquer. Rapid drying inhibits the wood grain from swelling. This eliminates the need for re-sanding after stain is applied to wood that is susceptible to grain raising, such as oak. Using long even strokes, apply the stain with a brush in several layers, rather than brushing on a heavy coat at the outset.
Penetrating stains. These stains combine pigment and dye, but have less pigment than standard pigmented stains. As the name implies, penetrating stains penetrate the wood, leaving very little color pigment on the surface. These types of stains are popular at home centers and hardware stores because they produce richer colors than plain pigmented stains. You can apply penetrating stains with a brush (usually recommended) or with a lint-free cloth.
Gel stains. These stains are made from either pigment or dye. What makes them stand apart is their physical consistency. Gel stains are so thick that they do not fill the wood grain. This makes them an excellent choice when you are working with a wood that tends to blotch, such as pine or woods that are highly figured (patterned), such as curly maple. You can lay on the gel stain, wipe away the excess, and get an even finish across the entire piece of wood. Gel stains are usually applied with a lint-free cloth. (Fig. 2)
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2.
Terminology
The liquid into which stain is mixed may be either water or solvent. Water-based stains are non-volatile, while solvent-based stains are typically volatile. Solid ingredients, called binders, are added to the water- or solvent-based liquid. Solvents dissolve the binders, which form the film of a coating and hold dry solids, or pigments, to the substrate (surface) being coated. Binders may consist of various synthetic or natural resins, such as acrylic, alkyd, copal ester, epoxy, polyurethane, polyvinyl chloride, or silicone. Together, base liquids and binders are the two basic components of paints and stains and form what is called a vehicle.
Water-based stains consist of dry ingredients mixed with water to form the vehicle. Because they do not contain volatile organic compounds (VOCs), they do not to have a noxious odor.
Solvent-based stains containing VOCs emit vapors when they evaporate. Aside from being noxious, such solvents are often highly flammable and can be dangerous if you don't follow the label directions regarding the use of protective clothing, equipment, and safety practices for preventing fire and explosion. (A rag soaked in a solvent may be subject to spontaneous combustion). When applying stain, be sure to wear a respirator and rubber gloves, and work in a well-ventilated area.
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3.
When to Use Each Type of Stain
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The type and color of stain you choose will depend on the wood you’re staining and the look you want to achieve. Here are some points to consider.
Wood grain: If your wood has distinct, interesting graining, such as cherry or walnut, choose a stain that will go deep into the wood and highlight the grain, such as a dye (non-grain-raising) or penetrating stain. Figure 3 shows a dye stain used to enhance the subtle grain patterns in a maple board.
If the wood you are staining has just average graining, such as pine, or is made from a highly patterned wood, like birds-eye maple, choose a pigmented or gel stain. This will darken the wood without causing the grain or pattern to stand out artificially.
Stains also react differently to a wood if it is tight grained or open grained. For example, with open-grained woods, such as walnut, mahogany, oak, or hickory, the pigment in the stain tends to become embedded within the grain, exposing itself in dark shadows. The effect is pleasing in some applications, but you may not care for it.
Wood species: Softwoods like pecan, pine, and some firs, may darken quickly once stain is applied. You may have trouble restricting how dark the wood gets. The opposite is usually true of hardwoods. Hardwood does not absorb stain readily; you may need to apply several coats of stain to achieve the degree of darkness that you desire.
As a general rule, choose lighter stains for softwoods and darker stains for hardwoods. You may even find that you get great results from simply brushing a clear finish, such as lacquer or varnish, onto hardwoods, instead of applying a stain.
Of course, the very best way to know how a stain will look is to apply it to a test section of your actual project. If you aren’t satisfied with the results, you can always choose a different stain.
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4.
Working with Stain
Here are a few finishing tips that you may find handy when working with stain:
* Work in a planned finishing area that is well lighted, well ventilated, and as free from dust and dirt as possible. This means that you should vacuum or sweep the area beforehand so that all dust can settle, instead of ending up on your surface.
* Working temperatures are important, ideally at about 70 degrees Fahrenheit.
* Avoid temperatures 50 degrees Fahrenheit or under or above 90 degrees Fahrenheit. Some manufacturers rate finishes by temperature. If it’s too cold or too hot, a stain may not dry well. Be sure to check the container label and take all safety precautions recommended, such as proper ventilation.
* Beware of high humidity. This can cause stains to remain wet for too long periods of time, allowing the grain to rise or dust to settle into the stain.
* Do not work near forced air heating or cooling ducts. These can stir up lots of dust to settle into wet finishes.
* Be careful. Many finishes are volatile.
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