Article: Glazes and Glazing Techniques
In this article we will discuss glazing, what it is, and how you can use this technique on your refinishing project. Glazing is the technique of applying stain in a certain order within your finishing process.
The glaze itself can come in numerous forms, including common stain, oil color, universal-tinting color or a specially made product called “glaze.” Think of glaze as a stain that is thick bodied so it will stay where you put it, even on a vertical surface.
By applying glaze between coats of finish you can add the appearance of age to furniture. For the opening photograph, I applied and left glaze in the recesses on the right side of a ball-and-claw foot.
Glazing is the act of applying, and then manipulating, color over a sealed surface.
The color can come in many forms, including common stain, oil color, Japan color, universal-tinting color or a specially made product called “glaze.” A glaze is simply a stain that is thick so it stays where you put it, even on a vertical surface. Gel stain, for example, makes a good glaze. Note that it’s the position of the colorant in the order of finishing steps — over at least one coat of finish, but under a topcoat — that defines glazing. You don’t have to be using a glaze to be glazing. On the other hand, even if you are using a glaze, you are staining, not glazing, if you apply it directly to bare wood.
Though it’s easy to do, glazing is still a sophisticated decorating technique because of the many effects you can create. These include adding depth to three-dimensional surfaces such as raised panels and moldings, faking the wear and dirt accumulation associated with age, adding definition to painted surfaces, adjusting color after the actual finishing has begun, and creating faux (fake) grain or other decorative patterns.
Besides its ease, glazing is also one of the most forgiving steps in finishing. You can actually practice on the wood you’re finishing, and if you don’t like the effect you get, you can remove the glaze and start over without damaging any of the finish.
Though the application of glaze is not difficult, there is skill involved in knowing the look you want to create (having an artistic sense), and in maintaining consistency when glazing multiple objects, such as all the doors on a set of cabinets.
There are two types of glaze: oil-base and water-base. Oil-base glaze gives a deeper, richer appearance and is easier to control because of the longer working time. You can remove oil-base glaze for up to an hour or more by wiping with paint thinner or naphtha, neither of which will damage any paint or finish.
Water-base glaze is more difficult to work with because it dries so fast. But it has much less solvent smell, so it is less irritating to be around. Once you've applied a water-base glaze, you have only a few minutes to remove it using water before it dries too hard.
Oil-base glaze is best for cabinets and furniture when the finish is lacquer, varnish or shellac, and you’re applying the glaze in a shop with good ventilation.
Water-base glaze is best for faux finishing on large surfaces like panels and walls in buildings where there is very little air movement, and on furniture and woodwork when you’re topcoating with a waterbase finish. To use a water-base finish successfully over an oil-base glaze, you have to let the glaze cure completely, which could take a week or more depending on the weather conditions.
Brands of glaze vary in thickness and drying time, but all brands produce good results. Some manufacturers provide glazes in a range of colors. Others provide only a clear glaze base to which you or the paint store add the pigment. Dark browns and whites (for pickling) are the colors most often used on furniture and cabinets.
If you need to thin a glaze to lighten its color, it’s usually best to thin it with clear glaze base instead of common thinner so you don’t lose the run-resistant quality. If you need to adjust the color of a glaze, you can do so easily by adding pigment ground in oil or Japan (which means varnish) to oil-base glaze, and pigment ground in glycol solvent or acrylic to water-base glaze.
You can use any finish, sanding sealer or paint under the glaze. You can sand this first coat if you want. But sand lightly with fine sandpaper so you don’t sand through, or the glaze will become a stain and color the wood. Sanding or steel wooling has the
benefit of roughening the surface so the glaze can bond better to it.
You can stain the wood under the sealed surface, leave the wood unstained or fill the pores of the wood. But in all cases, you should apply the glaze close enough to the wood so you can still apply one or more topcoats of finish to protect the glaze from being rubbed or scratched off without getting the overall finish build too thick.
Because there’s no build with oil finishes or wax, you can’t glaze successfully between coats of these finishes. You must use one of the film-building finishes.
To apply glaze, wipe, brush or spray an even coat onto the surface. Then manipulate the glaze with the following methods.
• Wipe off the unwanted glaze while it’s still wet. In most cases, this means wiping the glaze off raised surface areas and leaving it in recesses on carvings, turnings, mouldings and raised panels. But it can also mean wiping off flat surfaces in a way that imitates grain or other decorative effects.
• Wipe off the unwanted glaze right after the thinner has flashed off and the glaze has become dull. This is the same as wiping off while still wet, but the glaze is usually a little easier to control at this point.
• Using fine steel wool, abrade off the unwanted glaze after it has dried. There is a risk that you might abrade through to the wood, but it’s nice to know that you can always use steel wool to remove glaze if you don’t get enough off with a cloth before the glaze gets too hard.
• Using an almost dry brush, spread the glaze out thin to achieve the appearance you want. All this amounts to is continuing to remove glaze with a brush you keep fairly dry by wiping with a clean cloth until you achieve the effect you want.
• Adjust the color of the object you’re finishing by brushing glaze out thinly and evenly over the surface. As long as you keep the glaze thin, you won’t muddy the wood much. This is an excellent technique for creating a more perfect color match.
• Using tools such as rags, sponges, brushes, grainers and toothbrushes (to create a spatter effect), create a decorative faux pattern. Here, the techniques and colored patterns you can achieve are endless. Many books explain these techniques. Most are focused, however, on decorating walls rather than woodwork.
• Instead of manipulating glaze you’ve already applied, use a “dry” brush to apply the glaze to raised areas of carvings or turnings, or to flat surfaces to create the appearance of dirt accumulation. Begin with a totally dry brush and swirl it in some thick oil or Japan color you’ve applied to paper, cardboard or wood so that some of the color is transferred to the bristles without making them wet. Then brush lightly.
Most glazing problems occur because you've applied the glaze too thick or not allowed it to cure enough before applying the topcoat of finish. The two are related because a thick layer of glaze takes significantly longer to cure.
Too thick a layer of glaze (most common in crevices and recesses) weakens the bond of the finish to the wood because the glaze layer itself is not strong. The finish applied on top of the glaze could separate if knocked or abraded and this would pull some of the glaze with it and leave some attached to the surface underneath. This problem is even more likely to occur if the glaze hasn’t thoroughly cured.
Not allowing the glaze to thoroughly cure can also lead to the topcoat wrinkling or cracking. If this happens, you’ll have to strip the finish and start over