The importance of a good foundation surface—even, smooth, and free from unsealed pores that would absorb and thus undermine the first coat of varnish—has been explained in the section on filling and surfacing. If this foundation has been well laid, the amateur finisher may enter upon the varnishing stage of his work with confidence; but he will soon learn that there is much call for skill in order to produce the desired results in this part of the finishing process. The selection, preparation, and application of varnish is a special calling, and great skill comes only as the result of experience; but certain main facts and principles are easily learned.
How a Good Varnish is Recognized.—It is hardly necessary to say that a superior varnish must be clear, transparent, and brilliant. These qualities are always associated with this kind of finish. But durability is also a necessary quality. An expert will, with his eyes shut, recognize a high-grade varnish by its peculiar odour, which is to him an agreeable one. He will at once detect inferior grades by the rank, sharp odour of resin and benzine used in their manufacture. The range of quality and cost in varnishes is probably greater and more varied than in any other finishing material. For fine, artistic work only the best varnish is allowable; and this may be bought for $3.00 a gallon.
"Sag" and How Corrected.—A good varnish flows easily from the brush, spreads evenly, and dries slowly, thus allowing plenty of time for its proper distribution over the surface. And time enough should be taken to apply an even coat which will not dry unequally and lead to cracking due to irregular contraction in the process of hardening. It is of the utmost importance that each coat be spread evenly over the surface when first applied. Great care should be taken not to brush long in one place. Re-brushing after a brief interval leaves brush marks which are objectionable. Unequal spreading on broad surfaces often causes the varnish to run or "sag." A tendency to sag may be brushed out if attended to promptly. But, if it is not noticed until the varnish has begun to set, the only way to prevent a bad blemish is to absorb the thickening parts of the coat by means of a partly dried brush; and this must not be attempted three or four minutes after the varnish has been put on. By that time it will have become quite well set and a sag will be beyond repairing by any simple means.
Time Required Between Varnish Coats.—The best varnishes, as has been stated, dry quite slowly, and they seem to dry and harden not, as shellac does, on the top first, but from the under surface outward. This peculiarity emphasizes the need of allowing sufficient time between coats. And it should be added that mere drying is not all that is required. Each coat must harden; and during the process of hardening slight movements take place throughout the mass of the coat until it becomes permanently set or hardened. The time required for this permanent setting or seasoning, as it may be called, varies with the character of the under coat, with the temperature of the room in which the finishing is done, and with the thickness of the varnish coat itself. Five days is usually thought to be a short seasoning period. As many weeks would not be too long for the best results. It is folly to attempt to hurry up a job of varnishing. In the nature of the case it cannot be hurried without yielding disastrous results. There is no other kind of work in which "haste makes waste" with the certainty that it does in varnishing. Great pains must be taken with each coat. Least of all should the under coats be slighted, for solidity and depth in the appearance of the finished surfaces depend upon there being plenty of evenly laid and well hardened varnish before the final or finish coat is applied. All this work should be done in a well-lighted room, free from dust, and with a good supply of fresh air, kept at an even temperature, of about 70 degrees—certainly not colder than this, since a lower temperature prevents varnish from spreading evenly.
Number of Coats Needed.—The number of coats of varnish required vary with the character of the work. What is known as piano finish requires from three to seven under coats of good elastic rubbing varnish, each well hardened and rubbed down to give under surfaces more even than the best brushing can give. In addition to these under coats a final finish coat is needed to give brilliancy and lustre.
How to Rub Down Varnish.—Rubbing down varnish is a unique and important part in the process of finishing. The beginning of the operation consists of long and persistent rubbing with pulverized pumice stone mixed with oil or with water, if the work is such that water would have no chance to soak into the pores of the wood. Whichever liquid is used, a rubbing pad will be found necessary. This is a block about 4 inches square, made of thick, loose cloth like felt or hair cloth. In use it is first moistened in the oil or water and then dipped into a box containing a quantity of powdered pumice. With this the varnished surface is rubbed vigorously, giving a circular movement to the pad in rubbing down the broad surfaces. As the smoothing progresses, less and less of the pumice powder is used. Near the end of the process enough will be found on the surface or adhering to the rubbing pad. What remains on the surface is finally all wiped off carefully with chamois skin, when it will be found that the surface has been levelled down but that it is covered with fine scratches due to the grains of the pumice. These are removed by a second rubbing in rotten stone and oil or water.
Dull Finish and Flat Varnish.—For many purposes good finishing requires but one under coat rubbed down and covered with a finish coat; and this finish coat is often not allowed to retain its natural lustre. For furniture a dull finish is much to be preferred. It is more durable, it harmonizes better with its surroundings, and it is more in keeping with the idea of simplicity and usefulness. In working for a dull finish it is not so essential to secure depth and evenness of surface as it is when a high lustre is required, and therefore fewer coats are necessary. In fact, a dull finish may be given to furniture without any varnish at all. Two or three coats of shellac, each well rubbed down, give a very satisfactory result. Wax finish, to be described later, gives beautiful effects. There are varnishes known as flat varnishes which give a dull finish without rubbing. They are made by dissolving beeswax in turpentine in the proportion of two ounces of the solid to a pint of the liquid, using moderate heat and mixing the wax solution while warm with four times the quantity of warm varnish. What is known as the old Dutch finish is obtained by using over the proper stain one coat of wax varnish. But there is no kind of dull finish so durable as that given by several coats of high-grade varnish, each well rubbed down.
WAX FINISH
How to Prepare and Apply Finishing Wax.—The simplest and at the same time one of the most attractive methods of finishing woodwork is rubbing it with finishing wax. This is one of the old processes which has of late years been revived by the arts and crafts societies and is becoming deservedly popular. Finishing wax may be purchased ready for use or it may be made by dissolving yellow beeswax in turpentine in the proportion of two parts wax and one of turpentine. To do this the wax should be cut into small pieces or shavings, placed in a dish, and covered with the liquid. The solution may be hastened by heating in a water bath; but, if a gas flame be used for heating the water, care should be exercised to extinguish the flame before bringing the turpentine near, on account of the inflammable character of turpentine vapor. This mixture, which is too thick to spread with a brush, may be applied either hot or cold by means of a piece of soft cloth. Soft cloths, like clean cheese cloth, should be used also in rubbing. The rubbing should be continued for a considerable time, but it is by no means so tedious a process as the rubbing down of the several coats of varnish. Less rubbing is required if the wax is applied hot. One of the greatest advantages of the wax finish is that it may be quickly applied and immediately rubbed down, after which the furniture is ready for use. Filling and finishing are accomplished together. It is also easy to apply a fresh coat of wax at any time. In fact, it is desirable to re-finish new pieces of furniture in this way several times during the first few months of their use, and after that about once a year.