Finishing wood is both easy and more complicated than you may think. It’s easy because its requirements are not extensive. The tools are nothing more than brushes, rags, and spray guns. Only three essential substances make up most finishing materials—binder, pigment, and solvent. And in contrast to wood carving, little hand/eye coordination is required.
Finishing is complex because there are so many variables and so many things that can go wrong. And there is so little good information available about what to do when something does go wrong. One of the purposes of this blog post is to provide this information.
Overcoming The Fear of Finish: A page from Flexner
Many beginner carvers are afraid to attempt a finish any more complicated than brushing on a few coats of polyurethane or wiping on and wiping off some oil. They don’t understand finishes, and they’re afraid of ruining their carving. To remedy the situation, they look for techniques (tricks). What they really need is an understanding of the materials.
Because finishes are more difficult to understand than they are to apply, this article is devoted to explaining how stains, sealers, finishes, and polishes work and how to put these materials on the wood. This may be confusing at first, especially to a carver accustomed to finishing wood tutorials that emphasize techniques. But you’ll quickly see the more excellent value in learning about materials. And then, the techniques will make sense, too.
Why finish wood carving anyway
Finish a carving or just finishing, in general, is a step that not many in the woodworking crafts enjoy. It Finishing in most cases is smelly and messy and anything could go wrong at any moment. Additionally, most finishes will have a long drying period which will make you anxious while waiting. So why bother with this step? Let’s see.
Stabilization.
to new hobbyists, wood may seem like a stable material but it’s quite the opposite. Wood is both porous and hygroscopic properties that allow the wood to absorb and release moisture into the atmosphere.
A piece of wood will absorb and release moisture whenever the environment is extreme. For instance, if a piece is placed in water it will absorb the water and swell. Similarly, if a piece is brought to a very dry room or heated workshop it will shrink as it loses water in the dry environment.
These dimensional changes in wood are called ‘wood movement.’ The main problem with these movements is they do not occur consistently all through a piece of wood. The surface of the wood will respond more rapidly than the core. So a wooden board will shrink, warp or form splits on the width and thickness of the board, not the length.
using a finish seals the wood pores ensuring minimal or slowed moisture exchange in the wood hence stabilizing the wood.
Sanitization
Wood is a porous material that can collect and accumulate dust and grime over time. This can make the wood look unattractive and a health hazard. It is also hard to clean wood that is not finished as the rub only makes a smudge. Finishing wood ensures that the pores are sealed. Additionally, when we finish wood we make it easy to clean.
Finishing wood as a decorative approach
Finishing wood is not only good for stabilizing the wood and protecting it from dirt but also a decorative move. using a simple finish like oil does more than offer protection. As simple a finish as it may seem it make the grain of the wood pop. In the decorative finish we talk of three things; color, sheen, and texture. We discuss each below.
Changing the color
When we talk of color in finishing wood we are talking of paint and stains mostly. Paint is one of the best and easiest to apply finishes available. using paint will definitely prolong the carving or wood. maintenance is also easy. However, painting wood hides the wood, and at times that takes a lot from the piece. therefore as convenient as paint as a finish is it’s not always ideal for certain carvings.
Stain
Stain applied to a wood surface will pop the grain. Staining will also magnify imperfections in the carving such as tool marks, scratches, and uneven density in the wood. But this is not all bad and at times can be used for that reason to create artistic exaggeration, especially in whittling figurines.
Glazing
another type of staining is called glazing. Glazing is when color is applied in between coats of finish. When glazing is applied thinly it normally makes the wood appear of age and creates a depth by highlighting the pores and recesses. When applied thickly it can be artistically manipulated to imitate wood grain marble or leather. This technique is common in finishing wood cabinets.
Shading and Toning
When the color is added directly to the finish we call this shading or toning. the difference is how much impact it has on the color. This technique is quite useful when color matching is desired. For instance, carving a replica of a vintage piece and wanting to match the tint of the original. we have covered shading and toning vanish here.
Sheen
sheen is the amount of gloss a particular finish has. Some carvings call for high sheen and knowing how to achieve it is crucial. To control sheen there are two ways to approach it. one by picking a finish that’s inbuilt sheen. The options here are high gloss, flat or satin. The other is polishing the cured finish to the desired sheen.
Special texture effect for wood carving
Whatever the nature of the carving, striking effects can be obtained by processes that depend on the further development of the wood surface before applying a protective finish.
Burnishing
Burnishing is a method of producing a sheen on the wood by rubbing with a hard object such as wood, bone, or glass—or alternatively with a fistful of excelsior or shavings. Rubbed with a solid object, the wood develops beautiful, polished highlights.
Use the excelsior or shavings to obtain an overall sheen on a tool-marked surface. Steady, hard pressure is required as you rub. The softer the rubbing material, the longer the job will take. Machine burnishing can be done by mounting a smooth dowel in a power drill and carefully working the spinning dowel over the surface.
This is tricky, but it can be done effectively. Suppose lathe work has been involved in mal the carving. In that case, you may return the piece to the lathe and simply press a bit of hardwood against the smoothed surface as it turns.
Wire-brushing
Wire-brushing is more a texturing method than an authentic finish. Use a wire brush, working with the grain, to abrade out the softer springwood from between the layers of harder summerwood. This results in a highly textured surface, accentuating the natural grain pattern of the wood, The brushing may be done by hand, or a wire wheel may be mounted in a drill
to speed up the process.
Sandblasting
Sandblasting produces almost the same effects as wire-brushing by using air-blown particles of abrasive. Most large painting contractors and industrial painters can do this for you. It often leaves a slightly more pitted effect in the soft springwood areas.
Charred-and-brushed finishes
Charred-and-brushed finishes are produced by burning the surface with a gasoline, alcohol, Propane, or acetylene torch, then removing the burned material with a wire brush. The surface should
be burnt just enough so that red-hot, glowing lines appear under the flame but not enough so that the wood continues to burn when the torch is removed.
A lightly dampened rag is good for squelching any flames that remain. The end effect is texturally similar to straight wire-brushing. Depth of color is controlled by the severity of brushing. A light brushing, just enough to remove loose charred wood, leaves an alternately dull and shiny streaked black.
Medium brushing leaves the hard summer wood a glossy black and the softer, more charred areas deep chocolate to reddish-brown. Hard brushing lightens the black to gray-brown, the brown approaching the wood’s original color. Fir, pine, and redwoods with prominent spring/summer wood patterns are especially spectacular with this finish.
Surface prep before applying finish
Surface prep is a very important step that many beginners covers will assume. This step starts before the carving begins. It is very important to think of how you will finish your carving when selecting your lumber.
Doing this is very helpful in making the finish phase a success. It’s extremely important to inspect your wood and check the knots, shakes, and defects to see how to either work around them or take advantage of them.
The next step is sanding. Depending on where you stand sanding may be necessary or not necessary in the project. You can see whether to sand a carving or not.
Clean is also vital before we can jump to finish. For joints that were glued extra glue needs to be wiped clean. Remember some finishes will magnify dents and imperfections this is the last checkpoint for any necessary corrections.
Tools for applying finish
In finishing we don’t have a wide variety of tools. Just rugs, brushes, and spray equipment. dependent on your project and the type of finish being used one of the three tools will be sufficient to see you through.
When picking a rug look for something cotton it works better than polyester or synthetic fabrics. Be sure to know what brush works with what finish as not all brushes will give satisfactory results with the particular types of finishes. For instance, the guys at Wood Magazine give tips on finishing brush tips
Simple Finishes for wood carvings
Shellac
Shellac is a substance collected on the back of particular species of trees in Asia. The lac bug lays eggs and in the process produces the resin that is dissolved with spirits to make a shellac finish.
Shellac can be bought ready under several brands. Sanding sealer, Button, and white polish are all based on shellac. When using shellac be quick with your hands as it dries quickly. As the alcohol evaporates it does not lift the grain fiber.
The options when buying shellac are natural shellac usually brown or orange and clear bleached shellac. The natural shellac will usually work well with dark woods. check out how to apply shellac in 3 steps
Oils
Oils will work well with any hardwoods. They make the wood appear richer. Linseed oil is the most common oil finish used in this context. Linseed oil reacts with the chemicals in the wood but for the benefit of the visual appeal of the carving.
The biggest advantage of an oil finish is maintaining the authentic natural look of the wood while still offering a film of protection. There are other oil finishes that are a linseed oil alternative.
Waxes
Waxes are available as wood finishes in three categories.
- Mineral -Paraffin, Benzene
- Vegetable – Carnuba wax
- Animal – Beeswax
waxes are the least protective finish among the finishes. The only reason we use it is for its ability to retain the wood color while giving the wood a sheen finish. Wax doest darken wood like other finishes. Wax is ideal for carvings that are stored indoors and are not regularly touched.
water-based stains
Water-based stains have their pigment dissolved in water. These stains have a tendency to raise the wood grain. These stains are therefore suited for carvings that are sanded. They penetrate wood well and are first drying. Finishing wood with water-based stains can still be furthered with other finishes but sealing is required.
oil-based stains
Oil-based stains have pigments either dissolved in linseed oil or turpentine. they are the exert opposite of water-based-stains. they are not as penetrating and will take way longer to dry. Before furthering with another finish you need to seal with shellac or wax. But not all finishes will accept so experimenting at a small scale is required. They do not raise the grain and therefore are suitable for carvings that are not sanded.
spirit-based stains
These stains have their pigment dissolved in spirits. The stains do not penetrate as well as water-based but are quite first drying.
They do not lift the grain which makes them ideal for carvings that are not sanded. After sealing they are usually accepting of other finishes.
fuming
Woods that can react with ammonia like oak have been darkening by using fuming. Some dilute ammonia is used to paint the wood. The wood reacts by darkening. Fuming should be done in a tightly enclosed space.
conclusion
The finish is very vital to wood carving. it prolongs the life of the carving significantly. However, application of finishes is a skill that needs to be learned via experience and correct practice whatever you pick make sure it goes well with the carving theme and material.