Applying Stains - Canadian Woodworking Magazine

Wood Finishing: Try using stain to make even the most ordinary project look extraordinary.

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Applying Stains



Choosing a stain can be a confusing experience, as there are numerous types of stains and quite a few different manufacturers. Basically, a stain is any liquid that contains a colouring agent (a pigment, a dye, or a combination of the two) and a binder that bonds the pigment or dye 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 of stain. Dyes, on the other hand, are coloured soluble substances that dissolve in the binder, which is why you don’t get any goop at the bottom of the can. Synthetic dyes are referred to as ‘aniline dyes; they use solvents rather than binders.
 

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Alder – Unfinished (left), Oil (inside left), Gel (inside right), Water based (right)
 
Pigment stains remain on the surface of wood, lodged in pores and surface scratches, while dyes saturate wood fibres. Dye stains come in a much wider range of colours than do pigment stains, and they are more uniform in colouring 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 centres 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 (sliced off the log as it rotates on a lathe), and then glued, heated and pressed onto the plywood core, and finally sanded. Not only will the wood fibres 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.

For important projects I always buy ‘architectural’ or ‘cabinet’ grade plywood (welbecksawmill.comwoodshedlumber.com). Typically the face veneer on the good side will be one continuous sheet. Building supply stores typically carry a lower grade of plywood (and usually in a few common species). Often, the face veneer is made up of multiple parallel bands of veneer joined together and running the length of the sheet. The bands may not be matched, and more often than not there are even gaps in the glue lines. When a stain is applied, the glue lines will likely absorb stain differently than the veneer. While more expensive, cabinet grade plywood is consistently of better quality. Exercise caution when transporting, storing and milling the plywood; the sheets are unwieldy to handle and it’s very easy to dent or scratch them.

There are several products that simplify the task of carrying sheet goods, including the Gorilla Gripper (woodline.com) and Panel Tote (leevalley.com).

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 species (like ash or oak) you can sand up to 180 or 220 grit, but on close tight grained species (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 (which burnishes the pores and reduces their ability to absorb stain), or you can apply a wood conditioner.
 

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End grain – Sanded to 150 grit, oil stain and conditioner (top), sanded to 150 grit, no conditioner (middle), sanded to 180 grit, no conditioner (bottom)
 
It’s important to remove excess glue completely, particularly around joints.

I let the glue set for around 30 minutes and then remove it with a sharp chisel that I reserve for this purpose. I then use a card scraper or sandpaper to remove any residue that may remain in the pores. Prior to staining, ensure that you remove the dust; you can use compressed air (though you risk contaminating the wood if you haven’t installed an in-line filter to remove oil laden air from the air lines), a tack rag, or wipe the surfaces with a cloth dampened with mineral spirits (if you are using an oil based stain) or water (if using a water based stain). If you wipe it down with water the grain will rise, and you will need to lightly sand the raised wood fibres before applying the stain.

It’s good practice to make sample boards (from cut-offs of the solid wood and plywood from the project) to test the stain that you plan to use. If you anticipate using the same species of wood and colour 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 (or live with the darker 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. My preference is simply to use a gel stain. These thicker stains don’t penetrate wood grain as much as thinner liquid (oil or water based) 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.

Stains can be applied with a paintbrush, foam brush, by rag, or spray. 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. Of course, 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 colours, or where you need to match an existing stain as closely as possible, use dyes. Any stain will result in a darker colour if you leave it on longer, or if you re-apply it after the initial stain has dried.

Over the years I have tried stains from a number of companies, and the ones that I have had consistent success with are Varathane (rustoleum.com), Bartley (woodessence.com), and Circa 1850 (circa1850.com). The Varathane stains are made with clear soya oil to provide maximum colour clarity, and premium translucent pigments in a proprietary anti-settling formula that does away with the need to constantly stir the stain during application.

But don’t take my word for it; 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.




CARL DUGUAY