Part 10

_The Wire Form._--Concrete cement cannot be modelled like clay. In its formative state it is too soft for such manipulation. It must be supported in some way while it is being worked into the desired shape and until it has hardened. In general there are two methods of giving the necessary support: _viz._, by employing an interior framework or skeleton, generally of wire lath, which is permanently encased in the cement; or by using a plaster or wooden mould into which the material in a soft and plastic state is poured and from which it is removed when hardened. The latter method has been elaborated quite extensively for commercial purposes, because it readily yields an indefinite number of marketable results from the same moulds. The simpler wooden moulds may be easily made by a clever boy; and after a little experience he can soon learn how to mix the cement properly and mould a form successfully. For single pieces of concrete work, however, the wire forms are to be preferred. A suggestive illustration of this method is found in the following problem:

A CYLINDRICAL GARDEN VASE

The dimensions called for in this design are a diameter of 10 inches and a height of 8 inches. The wire form must therefore be made to approximate quite closely to these dimensions. A good material for the form is galvanized wire lath of 1/2-inch mesh. This problem will require a piece about 8 inches wide and 34 inches long for the convex side, and a piece about 10 inches square for the base. From the square piece a circle 10 inches in diameter should be cut out. A strong pair of tinners' shears will be needed for this purpose. In bending the long piece into the cylindrical form it is well to proceed slowly in order to produce an evenly curved surface--_i. e._, one free from angular bends. A good way to accomplish this result is to lay the piece down on a bench top and bend it up over a cylindrical wooden block. If nothing better is available a rolling pin will serve this purpose. When the bending is nearly complete, the two ends of the piece should be brought together, lapped over about an inch, and bound together with free ends of the strands of wire. A pair of pliers will be of great assistance. If this part of the process has been carefully done, there will result a cylindrical form 10 inches in diameter. The circular piece should now be attached to one end of this form by means of the free ends of the strands found there, bending the projecting wires over and clinching them at convenient points on the circumference of the circular piece where there are uncut meshes of the wire. The form is now ready for covering with the cement.

The first step is the mixing of the cement for what is known as the scratch coat. This is made by mixing Portland cement with fine, clean sand in the proportion of one part cement to two of sand. These ingredients should be thoroughly mixed together in the dry state, and then there should be added a small quantity of goats' hair, well picked apart. For the problem at hand about five pounds of cement will be needed and as much goats' hair as can be held in the hand. The whole should be thoroughly wet down with just the right amount of water. It is important that the mixture should not be made too soft. A scratch coat should be given a consistency that will enable it to be easily spread over the wire form and, at the same time, to hang well together.

When a sufficient amount of the right mixture has been obtained, it should be spread upon the wire form by means of a small mason's trowel or a large knife. It is well to begin at the bottom of the convex side of the cylinder, working upward, taking no pains to make this first coat smooth, since roughness is desirable, and paying no attention whatever to the inside of the cylinder, excepting to see that the cement is forced well through the meshes so that the whole mass will be held together firmly when dry. The inside is given a smooth coat as a part of the later finishing process. When the convex surface has been well covered, the form should be turned bottom up and the cement spread upon the base of the cylinder in the same way. After the wire has been completely covered, the form, which is likely to be somewhat distorted, should be corrected by careful manipulation till a true cylinder has been obtained. This is allowed to stand for about five hours until the cement has thoroughly hardened. It is then ready for the finishing coat.

The next step in the process is to make the cement for the finishing coat. Considerable variety is possible here, depending upon the colour and other surface effects that are desired. In this design a light, sparkling surface when finished is required. To produce this effect a mixture of one part Portland cement and two parts marble dust will be needed. This should be mixed without hair to a consistency like that used for the scratch coat.

Before applying the finishing coat the surfaces should be thoroughly moistened by means of a brush well filled with water. There are various methods of applying this coat. The simplest is carefully spreading it on with a trowel and smoothing it with the moistened hand. When the surface has hardened sufficiently it is sometimes possible to improve the finish by the judicious use of sand-paper or a coarse file. It is not possible to produce perfectly even surfaces in this way; and yet the method has the characteristic freedom of handwork in general, and yields very satisfactory results.

_The Decoration._--A great variety of decorative effects may be obtained in concrete pottery and in other articles made of this material for out-door use. In pottery these decorations may take the form of raised figures or ornaments, of borders or designs cut in the surface, and of inlays in colour. Whatever the form of design, the necessary cutting for it is best made when the cement has become well set but not very hard--_i. e._, from 6 to 10 hours after the finishing coat is applied. A stout, sharp, pointed knife blade is all the tool that will be required. A narrow chisel, however, may be found desirable for deepening the cuts. The knife should be guided by means of a ruler, which should be flexible if used on curved surfaces; and the depth of the cut will depend somewhat upon the size of the piece. In work similar to that described in the problem just given, a depth of 3/16 or 1/4 of an inch is sufficient. This cutting, of course can be made after the cement has hardened, by the use of hammer and chisel; but it will be much more difficult.

_The Colours._--Colour cement for inlaid designs is made by using the best quality of white Portland cement as a base, colouring it with dry mineral pigments which are sold by dealers under the name of lime or cement-proof colours. Among the pigments suitable for this purpose are red oxide of iron, which produces a red; oxide of cobalt, which gives a good blue; chromate of lead, which produces yellow; carbonate of copper, which gives a good dark green; and burnt umber, which yields a good brown. These come as dry powders and should be mixed with the dry cement and marble dust, making a mixture of uniform colour, before the water is applied. In order to determine the right colour it is well to experiment with a small quantity of the various ingredients until a satisfactory shade has been found. Then with this as a guide a sufficiently large quantity should be mixed, in the same proportions, to the consistency of a thick paste, and applied to the design, which has been previously cut in the surface to be decorated. To insure thorough adhesion of the paste to the concrete, the cutting should be well moistened with a wet brush. A number of suggestive designs are shown in the accompanying drawings.

_Rustic Furniture._--The lighter out-door furniture can be easily made up in a great variety of designs. The form of rustic settles and chairs is determined largely by the material which is available. Very useful and ornamental effects are produced by using sticks cut from the tops or from branches of small trees. Birch saplings, easily found in the second growth of some wood lots, afford a good supply of material. It is not necessary that the sticks be straight; the natural crooks and notches are often very useful in bracing the framework. Chairs, settles, tables, standards for flower boxes, and other articles of furniture may be made out of this rough and unfinished material.

_Lattice Work._--Trellises and garden screens have been made in an almost endless variety of forms. Among the most satisfactory is the plain lattice work in squares and rectangles. Its simplicity and evident durability are points in its favour. Experience proves also that vines and other plants needing support are readily adjusted to this form of trellis. The size of the stock required in making the right-angled lattice work depends upon the uses to be made of it. For a garden screen the uprights need to be of 2 × 2 inch stock and of any convenient length. End posts of 3 × 3 inch stock will be required, to give necessary stiffness; and, if the screen be a long one, intermediate posts of the same size should be placed at intervals of ten or twelve feet. The horizontal pieces may be strips of 7/8-inch stock, 2 inches wide, set their full thickness into the uprights. Spruce furring, which lumber dealers supply in 2-inch widths, is suitable for the small rails; but if chestnut be used for the uprights it is well to use the same wood for the rest of the construction. The top and bottom rails should be of heavier stock, not less than 2 by 3 inches. The best foundation is a line of concrete posts, firmly set into the ground at intervals of 6 feet, to which the bottom rail or the uprights are fastened by means of irons set into the cement when the posts are formed. Two coats of dull green paint will protect the wood and properly subordinate the lattice work to the trailing branches which it supports.

VIII

FINISHING AND RE-FINISHING

'Tis toil's reward that sweetens industry--_Ebenezer Elliot_

In the commercial production of furniture the cabinet-maker has nothing to do with the finishing of his work. This essential part of furniture making is turned over to artisans who are finishers by trade. In a separate part of the factory they attend to the cleaning and filling of the wood and to whatever finish is applied to the work of the joiner. It is hardly necessary to add that the finishing of all kinds of woodwork is quite as important as any other feature in its production; for, however good the lines of design may be and however thoroughly the design may be carried out in the construction of any piece of furniture or other woodwork, it may be and often is spoiled as a work of art in the finishing.

But the amateur cabinet-maker should be his own finisher. He should familiarize himself with the various kinds of finish that may be applied to the different woods. He should know the object of filling wood and how it is done. He should understand the processes of fuming, staining, and varnishing so well that he can produce with certainty the results desired.

CLEANING, SURFACING, AND FILLING

_First Steps in Finishing._--The first step in finishing woodwork is to clean it up and prepare it for the filler. Too great care cannot be taken in examining all surfaces for slight oversights that have occurred in the joinery work or for blemishes that have been acquired in any part of the process of construction. Light planing, chiselling, or scraping, and perhaps a little sand-papering, always with the grain, may be needed to remove these faults and blemishes. The most serious of these generally result from gluing. All surplus glue should be carefully removed, even to the film that soaks into the surface of the wood. The slightest spot of glue remaining will keep the filler out of the wood and show through any kind of finish.

_Importance of Filling._--As soon as the furniture is thoroughly cleaned, if it is to be finished in the natural color, the grain of the wood must be filled with a light, transparent, semi-liquid substance, known as the filler, which, after standing from five to seven minutes, should be thoroughly rubbed off with a piece of coarse cloth or a handful of shavings. This process, as its name indicates, fills the pores of the wood and protects them against the absorption of moisture and the consequent swelling. But this is by no means its chief purpose. Strictly speaking, filling is the ground-work of all subsequent finishing processes and, for that reason, it may be said to be the most important operation connected with wood finishing. If improperly done, no amount of good work with the varnish brush will remove the fault. In fact, good work is impossible after a bad beginning. Good varnishing or good finishing of any kind requires that, before the final finishing processes begin, the surface should be made perfectly level and smooth, free from all unevenness or roughness or minute openings of any kind that might allow the varnish or other finishing material to penetrate the wood. If the filling has not been so thorough that no part of the subsequent finishing material can be absorbed by the wood, a rough surface will be sure to follow. This may, of course, be rubbed down and re-finished, but never with that perfection of result which is assured by laying a good foundation in correct filling. It may be set down as a fundamental principle of wood finishing that the best result is obtained when the filling or surfacing has been so thoroughly done that the thinnest of finishing coats, few in number, are required to produce the desired result.

_Liquid Fillers or Surfaces._--There are many kinds of fillers in common use, but they may all be considered as belonging to one or the other of two classes. They are either liquid fillers or paste fillers. Woods differ greatly in the coarseness or fineness of their grain. The coarse or open-grained woods require a filler with body enough to close up the pores of the wood and give that perfectly even surface necessary as a foundation for good finishing. The close-grained woods, on the other hand, do not present the same filling problem. They could not absorb a paste filler. In fact, it is hardly too much to say that the fine, close-grained woods, like maple, gum wood, and birch, do not need a filler at all; and there are some coarse-grained woods, like southern or hard pine and cypress, the pores of which are naturally filled with gummy or resinous substances and will not absorb an artificial filler. But all such woods _do_ need to be given a finishing surface which will prevent the finishing coats from soaking into the fibre of the wood. This is the office of the so-called liquid fillers, which are very properly called "first coaters" or "surfacers."

_How to Make a Liquid Filler._--A standard formula for the preparation of a liquid filler is as follows: Mix four parts by weight of carbonate of soda with six parts of china clay, and grind this mixture in about eight parts of japan, thinning the product with turpentine or benzine to the consistency of linseed oil. Laundry starch may be used in place of china clay, giving a filler which is somewhat easier of application than the clay filler because it does not settle. It lacks in durability, however, especially if it is not well covered. The finest grained woods do not require the addition of any material to the filler to give body. A great variety of liquids may be easily obtained which, without being mixed with anything, will give the necessary surface.

Glue size, water glass, and the cheaper grades of varnish, thinned if necessary with benzine or turpentine, are often used for this purpose. But these are all inferior to the standard surfacers and never should be used on the best grades of woodwork. Shellac is always preferred as a first coater for hard pine, as it keeps the resinous sap in the pores of the wood and preserves the natural colour of the grain. If oil is applied to hard pine without first applying this protecting coat of shellac, the wood blackens with age. Shellac is an excellent first coater for other woods also. It is commonly used in house finishing as the surfacer for the interior trims. But it dries rapidly, and generally with a rough surface. The first coating of shellac, therefore, requires careful sand-papering before the varnish is put on.

_Time Needed for a Shellac Coat to Dry._--It may be well to caution the amateur finisher as to the time required for the thorough drying of shellac. While it may be truly said to dry very rapidly, the first drying is necessarily upon the outer surface, forming a hard coating which delays somewhat the drying throughout, so that a shellac filling is not really dry enough to sand-paper a half hour or so after it has been applied, though it may appear to be. It is a good rule to allow at least twenty-four hours for thorough drying; and it may be well to add that all methods of filling, rubbing off, etc., require for the best results more time than energetic workers sometimes allow.

_Cost of Surfacing._--A practical question that the amateur finisher will ask is, how can one know in advance how much filler is needed for given pieces of work, and what will be its cost? For a good quality of liquid filler it is safe to say that one pint will cover eight square yards with one coat. The cost varies greatly, depending upon the quality of the filler and whether it is home-made or obtained of a dealer. A good commercial filler or surfacer can be bought for $1.50 per gallon, making the cost per square yard of one-coat surfacing about 2-1/2 cents. A small can costs 15 cents. Good work cannot be done with the cheaper grades of filler. Shellac, which is, all in all, the best of surfacers, can be bought for $1.85 a gallon, which would make the cost of surfacing somewhat under 3 cents a square yard.

_How to Make a Paste Filler._--A good paste filler, such as is required for the open-grained woods like oak, ash, baywood, and poplar or white wood, may be made from pulverized and floated silica as a base, thoroughly mixed with raw linseed oil, turpentine, and japan in equal parts, with enough silica added to the liquid mixture to form a good paste of a consistency somewhat thicker than paper-hangers' paste. If the mixture should prove to be a little too thick, it may easily be thinned with turpentine. The final mixing of this filler requires grinding in a hand mill. Unless a considerable quantity of it is needed it is quite as well to purchase a can of the paste filler of a dealer in painters' or finishers' supplies, though commercial fillers are not generally quite so good as a one made on this formula. They often contain wax and whiting and other materials as a base which are not so satisfactory in the long run as the floated silica.

_How a Paste Filler is Applied._--Paste fillers should be spread on the surface to be filled very liberally with a wide, stiff brush, allowed to stand from five to seven minutes, and then rubbed off with a piece of burlap or a handful of fine shavings or excelsior. But it must not all be rubbed off or drawn out of the grain. This is an easy mistake for an inexperienced worker to make. The thing to do is to rub it in and at the same time leave the surfaces smooth. The surfaces should then be allowed to dry for about twenty-four hours before receiving the final finishing coats.

VARNISHING

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.