8.—The clear size is prepared as follows: Take one part of the melted glue, as already prepared, and mix it with two parts of water, adding a little of the ox-gall for the purpose already mentioned, and apply this mixture hot, when required, using a bristle brush for the purpose.
9.—The next step will be to prepare, for the purpose, those portions of the frame which require to be burnished. They must be coated with from three to four coats of burnish-size. Those portions of the composition work which are to be burnished should have one or two preliminary coats of Paris white, applied rather thicker than the white coats of pipe clay; and these coats of Paris white are prepared in the same manner as are those of pipe clay. These coats, of course, must only be applied after the portions of the moulding which are to be burnished have been filled up and smoothed down. The filling up is done with thick whiting, and the smoothing down is to be done with a wet rag.
10.—Many gilders use, as a primary coating for the burnish-size, a preparation which is called yellow clay. This yellow clay is supplied by dealers, and is to be mixed in just the same way that the burnish-size is. It gives a more elastic bed for the burnishing process; but the same result may be had by giving an extra coat or two of the burnish-size. I do not recommend its use, particularly for beginners. It only serves to complicate a process that is already complicated enough.
11.—The burnish-size, as it is supplied by the dealers, is not in a condition to be at once used, but must be prepared for that purpose in the following manner:
Take some of the crude burnish-size and mix it in a cup with water, add but little water at a time, and mix thoroughly, until the mixture barely drips from the spoon with which it is being mixed. Now add a teaspoonful or two of the hot glue already prepared. On stirring this up, the mass becomes very thick. Continue to add cautiously more glue until the whole begins to thin down, which it will do almost immediately. Perfect success in the burnish work depends almost entirely upon the proper mixing of the burnish-size. The various stages of the process must be invariably observed, just as they have been here described. If the operator exercises ordinary care only, he will rarely make a failure; though sometimes failure will occur, in spite of all precaution.
This lot of burnish-size may be treated also as a stock to be used from as required. Owing to the carbolic acid which has been mixed with the glue, it will keep from decomposition an indefinite length of time. Without that antiseptic quality imparted to it, it would spoil in a few days.
As now mixed, it will be found rather hard for the final coat or two, and it must be thinned down with thinner glue, or simply with water, for these coats; but for the first two coats it will be about right, and it must be made thin enough to lay smoothly and evenly on the flats and hollows without clogging the brush. When applied to the ornamental parts, it may be applied thicker. This burnish-size must be strained through the strainer. These strainers are procured from the dealers in gilding materials. Of course, the size will not run through the strainer, but it must be worked through by means of a bristle brush. It may as well be said here that all preparations should be strained, so as to avoid any particles of sediment which may be in the materials.
12.—Two or three coats of this prepared burnish-size must now be applied to those parts which are to be burnished, using a round camel’s hair brush for the purpose. These coats must be laid on very smoothly and uniformly. The first coat will go on rather crudely, owing to the absorption of the size by the under surface; but the succeeding coats go on more freely. The size should be applied warm, not hot, and the brush used for the purpose should be stirred up frequently, so as to separate the hairs and allow it to work freely. The surplus quantity must be removed from the brush by drawing it across the sides of the cup. The two final coats should be applied in the same manner, but the size used must not be so strong with glue.
When the final coat is dry, it will then be ready for the application of the gold leaf.
13.—The burnishing of a frame is generally done before the oil gilding. The application of the gold leaf is made in the following manner: