The Useful Arts Employed in the Construction of Dwelling Houses. Second Edition

by Anonymous

The Process of Burnish-Gilding.

We will take, as an instance, a long piece of the moulding which the paper-hanger applies in the way to which we have alluded. This is cut out to the proper hollow or reeded form by a carpenter, who employs planes suited for the purpose. The wood which he uses is of a kind tolerably free from knots and holes: and when the moulding is ready, it passes into the hands of the gilder. The first thing done is to wash it with a mixture of whiting and parchment-size, made quite hot, and almost as limpid as water. The size used for this and for other purposes required by the gilder, is obtained by boiling cuttings of parchment in water until a stiff jelly is produced.

When the moulding is dry from the application of this preparatory wash, any small holes that may exist are stopped up with putty, and the moulding is ready to receive five or six coatings of a very thick mixture of whiting and size. Those coatings are laid on moderately warm, by means of a brush, each coat being thoroughly dried before the next is applied. By this means the moulding is coated to the thickness of a sixteenth or twelfth of an inch, by which the fine squares and hollows produced by the plane (if there happened to be such in the moulding) would be liable to be stopped up: to prevent this, modelling tools of various forms are drawn along the wet whiting, so as to preserve the original pattern in tolerable condition. The whole surface is then smoothed by small pieces of pumice-stone worked to fit the various parts of the moulding. The stones and the whiting being kept constantly wetted, and the former worked steadily over the latter, a smooth and even surface is attained.

When the moulding is dry after this smoothing process, it is further smoothed with sand or glass paper, and is then coated with five or six layers of burnish gold size. This is a very peculiar composition of suet, black lead, clay, parchment-size, and other ingredients, mixed to a stiff consistency. These successive coats or layers are well dried after each application; and after one or two other processes by which the gold size is rendered smooth, the moulding is ready to receive the leaf gold.

Gold, in the form in which it is thus used, is one of the thinnest substances which the art of man has ever prepared in a solid form, since it would require more than a quarter of a million of the small sheets into which it is beaten, to make a pile one inch in thickness. A solid piece of gold is rolled into the form of a ribbon by means of a flatting-mill: and the gold-beater then reduces it to the thickness—or rather thinness—to which we have alluded, by means of hammering.

The gilder receives this leaf gold in the form of sheets or leaves about three inches square, inclosed between the leaves of a small book. He blows out some of these leaves on a leather cushion surrounded by a parchment border on three sides; this border, is to prevent the gold from being blown away, the fourth side being left open for the future proceedings of the workman. The gilder supports the cushion on his left hand, and with a knife in the other, he takes up one of the leaves of gold, and by dexterous management, spreads it out smoothly on the cushion. He then considers the width of the moulding, (which is laid before him,) and determines how he can best cut up the leaf of gold so as to adapt the pieces to the width of the moulding:—if for instance a slip one inch in width will cover the width of the moulding, he cuts the leaf into three equal pieces. He is next provided with a flat camel-hair brush, called a tip, the hairs of which are from one to two inches in length, and laid parallel with great regularity.

His tools being thus ready, he wets a small portion of the moulding by means of a camel-hair pencil dipped in water, and, taking the tip in his right hand, he lays the hairs on one of the slips of gold, which slightly adheres to it. This slip of gold he transfers to the moulding, where it instantly adheres by means of the water with which the latter is wetted. Another portion is wetted in a similar manner, and another slip of gold laid on, one end of which is made to lap a little way over the one first laid on. A third slip is now laid on in a similar manner; and by this time the first leaf of gold is all used. A second is therefore laid out smooth by means of the knife,—cut into three pieces,—and laid on the moulding as before. This process continues until the moulding has been gilt in its whole extent. We may remark, that the moulding is placed in an inclined position, the higher end being first gilt: this is done in order that the water should gradually flow off from beneath the pieces of gold after they are laid on, to facilitate the drying.

When the gold—or rather the wetted gold size which is beneath it—has attained a certain degree of dryness known only by experience, and which occurs in a time varying from one to twelve hours according to the state of the atmosphere, the gold is burnished by means of a burnisher made of flint, agate, or bone. This, if carefully done, produces a brilliant gloss, but could not be at all attained without the layers of whiting and gold size under the gold. Sometimes a portion of the moulding is preferred, for relief and contrast, to be left dead or matt, as it is termed. In this case the burnisher is not used; but the gold, after it is dried, is merely secured by a thin clear cement or varnish of parchment size.