Many new modern and synthetic products were introduced in the 20th and 21st century, leaving much of the traditional ways of finishing wood long forgotten. However, woodworking and finishing is an ancient craft and the oils, waxes, and resins historically used still produce beautiful results that are hard to achieve from most any other process. Whether you are restoring an antique or building a new piece of furniture, consider using a traditional finish.
Following are finishing techniques dating from the mid-1600’s to the mid-1900’s.
Oil Finishes
Linseed and tung oils are most commonly used, but other oils include walnut, soybean, sunflower, safflower, perilla, oiticica, and poppyseed. Linseed is pressed from the seed of the flax plant while tung oil is obtained from the nut of the tung tree. Oil finishes bring out natural characteristics of the wood and are relatively easy to apply. While it generally produces a satin sheen, applying many coats can produce a high gloss.
Varnishes
When natural resins produced from plants, trees, and insects are added to the oil or to alcohol (spirits) a varnish is created. In most cases, spirit varnishes are more transparent and colorless, but an oil varnish is tougher and more water-resistant. Oil varnish is difficult and dangerous to make due to the hazards of heating a mixture of highly flammable materials, so consider ready-made traditional varnishes. Shellac is by far the best of the spirit varnishes and is much more flexible and durable.
French Polish
Earlier recipes used other combinations and natural resins, but since the 1800’s, shellac, dissolved in alcohol, has been the main ingredient in a French polish. Applied with a pad, a good French-polish finish is very desirable and closely associated with fine furniture.
Shellac is made from the secretions of a lac bug and varies in color. Since it is solvent in alcohol, be careful of wine spills.
Stains
Classic stains consist of dyes or pigments derived from plants, trees, and insects and are used to color the wood. Dye stains are transparent and soak deep into the wood, while pigment stains contain crushed minerals resembling very thin paint. Colors will fade with prolonged exposure to sunlight. However, the newer developments of synthetic aniline dyes are more lightfast and often cheaper.
Stains which chemically alter the color of the wood have also been used for centuries. These stains can be very beautiful and enhance the natural beauty of the wood, rather than obscure the grain patterns, but dangerous chemicals are used such as ammonia and tannic acid.
Wax Finishes
Wax can be used alone as a finish or as a final protective coat. It is the most impervious to water compared to other natural products, but is relatively soft and damages easily. However, it is quickly repaired by adding another coat, protects against humidity, and produces a beautiful finish that is still preferred by many woodworkers.
Types of wax include beeswax, paraffin, carnauba wax, candelilla wax, lac wax, japan wax, and other waxes produced from trees, petroleum, minerals, and insects.
Milk Paint
Paint has been found on early Egyptian furniture and used for centuries to protect, decorate, and to hide crude joinery. Milk paint is one type from ancient origin that is very durable and has a distinctive look not easily replicated. Colors will fade with exposure to sunlight and the natural pigments of the earth are more subdued than other types of synthetic paint.
The main ingredients in milk paint are milk, lime, and earth pigments. You can purchase milk paint in dry powdered form with authentic pigments and correct coarse texture.
While there are advantages and disadvantages to each type of finish, it is these characteristics together that help make an antique look and feel old. Before disregarding a finish based on what you might think is an undesirable effect, remember that the faded colors of a stain, the dirt embedded into wax, or the rougher texture of milk paint is was gives furniture the distinct feeling of character, age, and patina.