Practical House, Wagon and Automobile Painter / including sign painting, and valuable hints and recipes

by W. F. White

The tools and materials required for glass gilding are the same as used for gilding in oil, excepting the gold size. Oil gold size would never do for glass work. In glass gilding the object is to get a size or mordant which will have the least possible tendency to destroy or mar the burnish of the gold leaf. This is absolutely necessary, when we consider that in this kind of work the size is before the gold, not as in oil gilding—behind it. For a mordant nothing can be better than the best isinglass. To prepare this for use the utmost care and cleanliness should be exercised. The water must be quite pure—free from grease or impurities of any kind. In preparing the size the following may be relied upon as a first-class recipe: Boil about one pint of water in a perfectly clean pan. Should any scum rise during the operation remove it with a large spoon. Then add about as much isinglass as will lie on a dime to the boiling water. This is best done a little at a time to prevent it gathering in a mass before it has a chance of dissolving. When the isinglass is dissolved strain the size through a fine silk handkerchief, folded double or fourfold, or, better still, through some white blotting paper. This straining or filtering will remove any bits or impurities that may have lodged unperceived in the isinglass. When cool the mordant is ready for applying to the glass. Some gilders like to add spirit in some form—generally spirits of wine—to their size. Their reasons for doing this are not always very explicit. Some do it because they have seen others do it. Others add it, they say, to give the gold a better burnish, or to make it better adhere to the glass. This is a delusion. The most sensible reason for its use was imparted to me by a veteran in the trade. He used spirits of wine to take out or kill any slight greasiness that may have been in the water or isinglass. I must confess that until I learned this, spirits always formed part of my mordant, because others used it. However, on further consideration, its use has been discarded, and, if anything, a better burnish on the gold is the result. In making the size it must be borne in mind that the less isinglass used the brighter will be the gilding when completed. Of course, if too little be used, the gold will not adhere to the glass as it should, and this would cause much damage and annoyance when the isinglass size was floated on again to proceed with the second gilding. When the size is too strong, or contains too much isinglass, no amount of burnishing will remove it altogether from before the gold. These are important points and should be carefully studied. But a little practice soon teaches the gilder how to arrive at the happy medium.

There are a variety of purposes to which ornamental glass gilding may be applied besides sign work, shop fronts or glass doors. It is now much used for show cases, window tablets, druggists’ bottles, fixtures and pilasters for shop fronts. Very often the design is embossed or bit into the glass, and worked up with gold and silver leaf, besides being picked out in colors. This is both a costly and effective method of decorating, which shall have full consideration in a future chapter. For the present it will, no doubt, be advisable to consider the simpler form of glass gilding. When this is thoroughly understood very little further instruction is needed for high-class work.

For the sake of example we will suppose a glass slab about three feet six by twelve inches is the subject to be treated. This is to have black letters without thickness or shadow on a gold ground. There are two methods of doing this. One is to first paint on the glass the letters with japan black and afterwards gild the plate. The other consists in first gilding the plate solid and then painting in the background with japan black. By this method the lettering is left untouched. The gold on these is then washed off, the edges trimmed, and the letters themselves painted black or any other desired color. This latter is, perhaps, the most satisfactory. However, a few lines of explanation will be devoted to each process.

First in order comes a plate, the letters on which are painted with japan black previous to gilding. To the learner, no doubt, the plain block letters will prove an attraction, because of their simplicity. This should be set out correctly on a sheet of lining paper. It will only be necessary to run in an outline of the letters. When completed to the satisfaction of the operator it may be pasted round the edges and fixed on the face of the glass. The back of the glass, that is the side upon which the work is done, should be quite clean. When the plate is fixed on an easel or stand, which is the most convenient place for working, the letters will, of course, read backwards. In this form they must be painted. When quite dry and hard, should the outlines of the letters be irregular, they may be set right in a very simple manner. All that is required to accomplish this is a metal straightedge and a sharp quarter inch joiner’s chisel. The straightedge is laid across the tops and bottoms of the letters and the chisel is employed to cut them sharp and true. The sides of the straight letters are then similarly treated; curves must be perfected with a writing-pencil. The paper may now be taken from the face of the glass and the plate examined all over. Should any specks of black be found on it they must be removed before the gilding is gone on with. The smallest speck shows up before the gold leaf. If convenient, before gilding, have the plate fixed at an angle of about 45 degrees. While in this position take a flat gilder’s mop and float the isinglass size over the glass. Then take up the cushion, take out a few leaves of gold from the book, and whilst the glass is wet cover it with gold, lifting the gold from the cushion as described in the last chapter. If possible lift a whole leaf at once, but should this at first prove troublesome try half a leaf. Keep the glass wet with the size and overlap slightly each successive leaf of gold until the whole of the glass is covered.

The glass must now dry before it can be re-gilded, and must then be gently rubbed with the finest cotton wool. It is an easy matter to ascertain whether it is dry or not. When wet the gold, if looked at from the front of the glass, has a dead look, but if dry it shows up bright. If possible leave the plate till next day before giving it a second coat of gold. The advantage of this delay is obvious. The gold has time to get hard, which materially reduces the risk of its being removed when a second application of size is necessary.

To the novice it will, no doubt, appear at first sight both a waste of time and gold to gild all over the work again, but if the plate be held up to the light it will show many imperfections in the shape of small holes, cracks and imperfect joinings. Another coat of size floated on and another layer of gold over the whole of the work should turn out a so far satisfactory finish. Let the glass dry again and be subjected to a further examination for faulty places. Should any be found cover them with more gold. But if the work is satisfactory it is ready for the burnishing process. The first stage is to polish the gold by gently rubbing with fine cotton wool, care being taken not to scratch the gold. This is, of course, only a repetition of the polishing after the first layer of gold.

There are several methods in general use for obtaining that brilliant burnish so much admired in glass gilding. But the one that meets with most favor and success is what is called the “hot water burnish.” It will be advisable to practice on the glass under consideration. After the cotton wool polishing is completed warm the glass either by holding it before a fire or gently pouring warm water over it. This is only a precaution against breakage by sudden expansion. Now let it dry, and while warm polish again with the cotton wool. Repeat the pouring of water, hotter than the last, and when the glass is dry, after this operation, gently rub it again with cotton wool. This hot water flushing should be carried on until the burnish is quite satisfactory. But it must be very carefully done, else the gold runs a risk of being washed off in patches.

HOW TO ESTIMATE WORK.

Measure your work with the tape-line and be sure you get all there is in it; projections, depressions, mouldings, edges, etc.