Restoring Lacquer And Varnish Finishes
A QUICK HISTORY OF VARNISH AND LACQUER FINISHES FOR FURNITURE
The terms "lacquer" and "varnish" are both used as generic terms referring to any finish which builds a resinous surface layer over the wood to beautify and protect it. Until sometime in the 1930s, the resins used in all finishes were extracted from natural sources, most commonly resins from a variety of species of trees. Synthetic resins, such as urethanes and acrylics have largely replaced the natural resins in modern finishes.
Although the two terms, varnish and lacquer, are used somewhat interchangeably, they do refer to two different types of finishes.
Varnish refers to finishes that combine one of a number of vegetable oils, such as linseed, tung, soybean or walnut, with one of a number of resins, and a dissolving solvent, usually turpentine. Varnishes formulated with these components have been in use since at least the late Medieval period. Synthetic resins developed in the past century are typically combined with mineral spirits. For all varnishes, the percentage of oil to resin determines the penetration, flexibility and drying time of the varnish, although varnishes are always relatively slow drying.
Lacquer is generally distinguished from varnish by the fact that it dries quickly and does not include any oils in its formulation. However, furniture and other items have been lacquered since prehistoric times in Asia using a slow drying non oil based formula that yielded a beautiful and durable finish. The resins used in most of those lacquers could cause severe allergic reactions and the lacquers needed to be applied and dried in an environment combining high heat and high humidity. For these reasons the craft of lacquering was highly regarded but not easily accomplished. Modern nitrocellulose lacquer was invented in 1921 and combines a cellulose resin with a combination of fast drying solvents. The speed of cure, efficiency of use, durability and beauty of these finishes quickly made them the finish of choice for furniture. Primarily to increase hardness and chemical resistance, synthetic resins and new curing technologies were developed in the later half of the twentieth century. Due to the toxicity and flammability of the solvents used in lacquers, solvent based coatings are in the process of being replaced with water based coatings.
PROS AND CONS OF LACQUER AND VARNISH AS FURNITURE FINISHES
WHAT CAN BE DONE TO RESTORE VARNISH AND LACQUER FINISHES?
One of the most common problems with most finishes is that they are simply dirty. The accumulation of waxes, polishes, smoke and dust can become so heavy that the the beauty of the finish and the pattern of the wood grain can be obscured. This problem can be successfully remedied by virtually anyone. There are solvents formulated specifically for this work, such as the Wax & Polish Remover by Liberon. Mineral spirits, also known as paint thinner, works well, as do some of the new citrus based cleaners. Murphy's Oil Soap is a very mild cleaner and may or may not be aggressive enough for your need, you would need to test it. The technique for cleaning with these is simple. With the solvent, use 0 to 0000 grade steel wool. The general rule is that the glossier the sheen of the finish, the finer the grade of steel wool, however, the coarser the grade, the more aggressive at cleaning. For most cleaning, we use 0 or 00 grade steel wool, but you will need to determine which will be the best grade for your project. We like the wool made by Liberon best, it is worth the extra expense. Wet the steel wool with the solvent and gently scrub the surface. You may start out gently scrubbing with a circular motion but then finish up scrubbing with slightly more force in the grain direction. Wipe the surface down with disposable towels. If the surface is sufficiently clean, you are done, otherwise, repeat this process until the surface is clean. Many older lacquer finishes have become soft and tacky feeling in places, especially when warm. This degraded finish will usually come off in cleaning, which creates a bigger job, but enables you to see more clearly the true condition of your furniture's finish.
Finishes that still adhere to the wood but even after cleaning are dull or worn, hazy or opaque, may possess the capacity to be revived and thus saved. For historically valuable pieces this is important, and for any of us who may not possess pieces of that import but who still value the features and appearance of the old, this is good news.
After cleaning, most pieces simply appear dull or worn and may have minor nicks or scratches. Applying a coat of a fine paste wax with an appropriate color blended in will eliminate the discoloration of the nicks or scratches and give the piece an even, soft, satiny sheen. For this we use Liberon's Black Bison paste wax, and strongly recommend that you do too. We have tried every widely regarded wax we have heard of, none are better than Black Bison. Black Bison uses highly refined liquifying solvents and so has a very low and not unpleasing odor. It buffs well and has an appropriate sheen. Black Bison waxes are sold in liquid and paste forms and in the paste form is offered in fourteen colors as well as neutral. Have we convinced you yet? In addition to the minor appearance flaws listed above, there may be areas where the color has worn off or perhaps there is a cloudy area from excessive water contact. Issues like these should be addressed before waxing. Re-stain with an appropriate color of wood stain to replace missing color. Use Liberon's Ring Remover to eliminate most cloudy discolorations.
In the effort to revive a more severely degraded finish, such as one that has crazing or wrinkling, varnished and lacquered surfaces need to be approached differently. The basic idea in reviving a lacquer finish is to soften the finish so that the surface imperfections level out and heal. This is done by the application of the appropriate thinning solvent, lacquer thinner, plus some other solvents to slow down the action of the thinning solvent. With varnish, for which there is no thinning solvent after the finish has cured, until recently it has not been possible to revive a severely degraded finish. In the last several years, artifact conservators have begun to explore the use of some new coating materials which will heal a varnished surface without altering it.
Although it is a time consuming and somewhat fussy job, most people can revive minimally distressed lacquer and varnish finishes. However, if you have a more severely degraded item or if you just want to be sure to have your piece done as well as it can be done, please bring it to us. We can help you.
There are times when the finish is so badly worn or damaged, or when a water stain has blackened the wood beneath the finish, that the finish simply must be removed and a new coating applied. For the best result possible removing the old finish and applying a new, of course you will want to bring it to us. However, you can achieve a good result on your own using a top quality stripper sold at a hardware or paint store. For more information on how to most successfully remove a finish, see our page on furniture stripping. Varnishes are commonly applied by a brush, so reapplying a varnish finish is quite doable at home. However, lacquer is best applied by spray, so if you want a lacquered finish you will need to consider taking your piece to a refinishing shop, like ours, to have its finish applied. Be aware, however, that in many states, the formulations for these finishes have changed due to environmental concerns and you will not be able to get either a lacquer or a varnish just like the original There are formularies available for varnishes, so if you are very ambitious, create your own varnish, just like they did a few generations ago. If you do decide to try the finishing work yourself, be sure to practice your skills on a scrap before you try working on your furniture item.
CARE OF A LACQUER OR VARNISH TYPE FINISH
The primary cause of degradation in both lacquer and varnish finishes is exposure to light and air, especially polluted air. In order to use and enjoy such furniture it needs to be where we are, in a lighted and airy room. So, the lesson to be learned here is that over time these finishes will age and degrade if we choose to use and enjoy them. However, we can slow the aging process by minimizing the exposure they receive to strong light sources and polluted air.
The second greatest cause of degradation for these types of finishes is the repeated use of polishes or oils, especially those which contain solvents like toluene. These solvents soften the finish and with repeated use can also introduce chemical changes which break down the structure of the finish. Human body oils will also cause degradation of finishes. Doilies over headrests or the hand rest of a chair arm are ways our ancestors have attempted to minimize this source of degradation. If you don't mind the way it looks, these methods will help to save your lacquered or varnished furniture as well.
Lacquered or varnished surfaces can be kept clean by dusting with a dampened cloth. A weak soapy solution can be used if there are oily marks or smudges that will not come off with damp dusting. Polishes could be used to accomplish an emergency clean and shine, but should not be used for routine maintenance. Besides the effects mentioned above, another adverse and unexpected result of regular polishing is the accumulation of a layer of dust trapped in the polish as it slowly evaporates. A layer of wax will protect the finish from the minor scratching and scuffing which come during the course of normal use. Since wax is dissolved in a solvent, repeated, frequent use of waxes containing lower grade or aggressive solvents can have the same degrading effect as oils and polishes. However, waxing a piece once every year or two is a good way to extend the life of a lacquered or varnished finish.
Both Lacquers and Varnishes provide fairly hard, durable finishes.
These finishes accentuate and add to the natural beauty of the wood surface they protect.
These finishes require minimal effort to maintain.
Lacquers dry quickly.
Lacquers can be polished to a mirror-like reflection.
Lacquer finishes are relatively easy to repair.
Varnishes dry very slowly, increasing production cost and risk of damage during production.
Both finishes can crackle or craze with age.
Both finishes darken with age, especially varnishes.
Lacquers, and varnishes which use mineral spirits as their solvent, use solvents which are highly flammable and which are also restricted or prohibited for industrial use by environmental rules.
Both finishes can become cloudy when subjected to prolonged contact with moisture sources.