How To Color Your Wood

While just about all wood is beautiful, not all the pieces of wood we work with are perfect.  Sometimes they need a bit of color. Normally we pick and choose through various stacks of lumber looking to acquire boards that match reasonably well in grain and color. Sometimes we end up with boards that have a bit too much sapwood in an otherwise field of darker heartwood. In cases like this, when the appearance is less than harmonious, we can choose to color the wood to even out those variations. Stains and dyes are the two most common ways of coloring wood.

Choosing a stain can be a confusing experience, as there are numerous types of stains. In a broad sense, a stain is any liquid that contains a coloring agent (usually a pigment, but can be a combination of pigment and dye) and a binder that bonds the pigment to the wood. Pigments are finely ground, insoluble, natural or synthetic materials suspended in a binder, which is why they typically settle to the bottom of the can. Dyes, on the other hand, are colored soluble substances that dissolve in the binder, which is why you don’t get any goop at the bottom of the can.

Pigment stains remain on the surface of wood, lodged in pores and surface scratches, while dyes saturate wood fibers. Dye stains come in a much wider range of colors than do pigment stains, and they are more uniform in coloring wood, but they fade much more quickly in direct sunlight than do pigment stains. Stains that contain both pigments and dyes obviously benefit from the qualities of both. In most hardware and home improvement centers you will find oil stains, varnish stains and water-based stains. Oil and varnish stains also come in a ‘gel’ formulation, which contains a substance that resists flowing.

On a lot of projects woodworkers use the same wood species in both a solid wood form and as a plywood. Cabinet sides, shelves, and doors are often made of plywood, with the framing done in solid wood. Typically any exposed edges of plywood are covered with solid wood edging. Again, this can pose a problem when applying a stain. The veneer on plywood is very thin, so thin on some brands that you can easily sand through the top in a matter of seconds with a random orbital sander. The veneer is usually rotary cut and then glued, heated and pressed onto the plywood core, and finally sanded. Not only will the wood fibers be crushed, it stands to reason that some of that glue will migrate to the top surface of the veneer. It’s no wonder that the plywood will take stain differently than the solid wood.

Proper sanding of both solid wood and plywood is a key to achieving optimal results when staining. Make sure that you do a final sanding by hand, in the direction of the grain. Shine a light across the surface of the wood at a 45º angle; it will help you see any imperfections that need attending to. On coarser open grained wood you can sand up to 180 or 220 grit, but on close tight grained wood (such as maple and cherry) sand up to 120 or 150 grit. If you sand these woods too smooth they will have difficulty absorbing the stain.

Pay special attention to end grain. The deep open pores provide cavities for the stain to lodge, which is why end grain usually stains darker than face or edge grain. You can reduce this by either sanding the end grain much smoother or you can apply a wood conditioner. It’s also important to remove excess glue completely, particularly around joints.

It’s good practice to make sample boards to test the stain that you plan to use. If you anticipate using the same type of wood and color of stain again, record details on the back side of the sample boards and retain them for future reference. It’s very discouraging to discover that the stain you just applied to a finished project is much too dark. If it’s a pigment stain you’ll likely have to sand down to bare wood in order to apply a lighter stain. If you used an aniline dye you can easily lighten the stain by applying its solvent, even after the dye has dried.

Some woods, such as pine, cherry, and birch, are blotch prone – they absorb stain unevenly. There are two options to deal with woods that blotch. One way is to simply to use a gel stain. These thicker stains don’t penetrate wood grain as much as thinner liquid stains. The second option, which you can try if you choose to use an oil or water-based stain, is to apply a wood conditioner before staining. The wood conditioner will help the wood absorb the stain more evenly. Be generous with the conditioner and remember to wipe it off before it dries on the wood.

Liquid stains, particularly water-based stains, dry fairly quickly, so on large surfaces you want to maintain a wet edge, to avoid lap marks. If they do occur lay on a second coat of stain after the first one has dried. The best way to avoid this problem is to spray on the stain. On any project that will likely be exposed to direct sunlight, use a pigment stain – it’s much more lightfast. For projects that require vibrant, bright colors, or where you need to match an existing stain as closely as possible, use dyes. Any stain will result in a darker color if you leave it on longer, or if you re-apply it after the initial stain has dried.

You really need to try several different stains to find one that suits your needs. Most are available in half-pint sizes for around $5 a can. Once you’ve latched onto a stain that you like, experiment with it on the woods that you typically build with. Try different finishes on top of the stains as well.

You wouldn’t expect to cut perfect dovetails the first time you try, so you shouldn’t expect to get perfect staining results without some practice. But you will be surprised just how easy it is once you’ve invested a little time in honing your staining skills.