Wood trim, wood cabinetry, and other woodworking projects usually receive a finish of wood stain followed by a protective coat of some kind of varnish. Unless the natural wood is top-coated in its natural state or is painted, stain-and-varnish is the finish of choice for the vast majority of woodwork and woodworking projects. Staining is particularly well suited for bringing out the best in the appearance of quality hardwoods, and it also helps highlight a woodworker's skill. Paint, on the other hand, is often used to cover up blemishes or hide woods that are less than ideal, such as inexpensive pine.
Will Stain Enhance the Project?
It perhaps goes without saying, but the first step in a good stain job is making sure the project is one that will be truly enhanced by a wood stain. Is it a project that you really want to show off? If the wood a type that is beautiful enough to highlight with a stain? For example, if you've built a large cedar-lined blanket chest with full through dovetails on each corner, you might not be too eager to show it off if the dovetails don't line up properly, or if there is glue run-out on the joints that causes blotchiness and uneven absorption of the stain. Such a project is almost certainly better suited to painting. And a project built from fine walnut demands a finer treatment than one made from plain poplar with almost no visible grain.
Assuming the project and the wood is worthy, what are the next steps?
Choosing the Right Stain
Not only are there hundreds of stain colors to choose from, with each of those colors you have a variety of choices when it comes to the type of stain.
Pigment stains vs. dye stains. All stains can be categorized as one of two types. In basic terms, pigment stains contained colored dirt that is ground up into fine particles. Dye stains, on the other hand, are soluable salts. When mixed with solvent, the dye crystals break down into individual moelcues that are much smaller than pigment particles. This means that dye stains can get into spaces where pigments cannot. In woods with dense grain, such as maple, pigment stains tend to wipe off while leaving little color behind, while dye stains do a good job of adding color. But with open-grained woods with large pores, such as oak, pigment stains lodge into the pores and do a somewhat better job of coloring than do dye stains.
Most commercial stains that you buy off the shelf in cans will be pigment stains, though there are a few dye stains sold this way. Usually, dyes are prepared by mixing dry powders in solvent, and thus are used mostly by professional woodworkers. If you want to experiment with dye stains, a woodworking store is where you should shop; you won't find these on the shelves at your big box home improvement centers.
Oil stains. Most widely available, these are what most people think of when they think of stain. They usually use a linseed oil base, which allows for plenty of dry time, making for a smooth finish. Oil stains can be identified by the type of thinning and clean-up solution that's called for. If the product calls for mineral spirits (paint thinner) as a clean-up solution, or lists "petroleum distillate" as an ingredient, it is a oil stain.
Most oil stains contain a mixture of both pigment and dye, and some contain only dye. Oil stains can be either wiped on or brushed on, but they are more suitable for brushing than are water-based stains.
Water-based stain. As the name implies, these stains use water as the binder and solvent. This makes them easier to apply and less toxic and smelly. They can be identified by labels that list water as the thinning agent and clean-up solution. Water-based stains are best if you plan to use a water-based top finish; water-based varnishes often don't bond well over oil-based stains. But water-based stains can be more difficult to apply because they dry very quickly and tend to raise the grain on the wood. Special preparation steps are required, including "raising the grain" with water and lightly sanding before staining. Water-based stains are usually rubbed on.
Gel stains. The stains known as gel stains are really nothing more than very thick oil-based stains. They clean up with mineral spirits. Gel stains are rather messy to apply (rubbing is the standard method), but they provide a smooth color and rarely cause blotching, even on pine. Gel stains are really the only choice when you are staining pine or another softwood.
One-step stain-and-finish. A recent time-saving innovation is a combination wood stain and varnish product that mixes the coloring agent and the top coat in one product. They are sometimes called varnish stains. They come in both oil-based and water-based forms, and are sold under labels like "One-Step Stain and Poly." These products are similar to finish known as Danish oil, which has been used for many years. Stain-and-poly products are usually brushed on, while Danish oils are applied in a single flooding coat that is quickly wiped off.
These products both colors the wood and then harden to a top-coat finish. Applying multiple coats causes the color to deepen. They can also be top-coated with a traditional clear polyurethane varnish once you've achieved the color you want. Some of these products say that they can be applied over the top of existing stain and varnish, making them a good option for rejuvenating worn surfaces.
Some woodworkers are a bit scornful of these time-saving products, but in fact they work fairly well. Very high-quality woodworking pieces might not be the best place to use one-step finishes, but they have a perfectly acceptable role in other applications.
Many otherwise find woodworking projects have been sullied or ruined when the woodwork rushed the preparation steps and applied stain and finish to word that wasn't ready for it. The first step to a great wood stain finish is to sand the project thoroughly. You can decide whether you want to use a sanding block or a random orbital sander to do the lion's share of the work. Either way, begin by sanding the project well a few times using using progressively finer grits of sandpaper as you go. When you're done, finish with a hand sanding with very fine paper for a final touch.
Some woodworkers gauge the quality of the sand job by placing an old nylon stocking over a hand and rubbing it all over the project. If the nylon snags on any portion of the sanded area, you've got more sanding to do.
After sanding the project thoroughly, the next step is to get rid of all of the sanding residue. Start by vacuuming the project as best you can with a wood shop vacuum. Put the brush attachment on the end so that you don't scratch your sanding job with a plastic vacuum tool or hose end. After vacuuming, go over the entire project once or twice with a tack cloth to remove any remaining fine dust.
Before you apply the stain to bare wood, it's helpful to apply a coat of pre-stain conditioner. This conditioner helps prevent streaks and blotches and ensures the stain will be absorbed more evenly. It is a good treatment for all woods, but especially for pine and other softwoods. Make sure to read the instructions before you apply the pre-stain conditioner. In some cases, the manufacturer advises that you wipe the conditioner off after a few minutes, and then apply the stain within two hours. Also, some pre-stain conditioners have a tendency to lighten the color of the stain, but you can combat this by applying a second coat of stain.
Wood stain can be applies with a paintbrush or foam pad, or it can be rubbed in with a clean cloth. Your choice of methods depends partly on your personal preference, but each type of stain is best suited to certain methods. If you're going to use a gel stain, apply it with a rag and wipe it down once the desired color is reached. Gel stains should not be applied with a brush or pad.
With oil-based stain, you have the option of either rubbing them in with a cloth, or applying by brush. If brushing it on, make sure to chose a natural-bristle brush, such as pig-bristles. Some woodworkers like to brush on oil-based stains, then rub the surface with a cloth to ensure even coverage.
Water-based stains dry very quickly, so they are often rubbed on with a cloth, though they can also be brushed on with a synthetic bristle brush. Don't use natural-bristle brushes with water-based products, as the bristle because saturated and limp.
With any stain, a deeper shade can be achieved by applying a second coat of
One-step finishes that include polyurethane topcoat should be applied in very thin coats, using a natural-bristle brush for oil-based products, or a synthetic-bristle brush for water-based products. Where necessary, a second coat can be applied after a light buffing with fine steel wool and wiping with a tack cloth.
No matter which type of brush you use, buy a good one and take care of it. If you're going to spend the money to buy a good brush, keep it clean and it will reward you with better finishes and will last longer.
Applying a Top Coat
The last step is to apply a protecting top-coat layer. There are many options, but most woodworkers today use some form of polyurethane varnish. Most woodworkers recommend matching the top coat with a product that has the same solvent base as the stain—a water-based varnish over water-based stain, or oil-based varnish over oil-based stain. Some manufacturers do claim that their products will adhere to a stain of any type, it is best not to test this unless the manufacturer expressly says it is allowable.
Application should be with a brush—natural bristles to apply oil-based varnishes, synthetic bristles for water-based products. A very common mistake is to shake a can of polyurethane varnish before applying it. While this is a common way to mix paint, it has a disastrous effect with poly, since it introduces tiny bubbles that can badly flaw the wood finish. Instead, thoroughly (and slowly) stir polyurethane varnish before applying it.
Two or even three coats of varnish are often necessary to provide a good protective coat. Apply them in thin layers, lightly sanding with 220-grip sandpaper and wiping down the surface between coats.