Glazing, as it is now practised, embraces the cutting of all the varieties of glass manufactured for windows, together with fixing it in sashes by means of brads and a stopping of putty; also the forming of casements, and securing the glass by bands of lead fastened to outside frames of iron. The most ancient species of glazing was in head-work, as our numerous cathedrals and religious houses still extant demonstrate; and fixing glass in leaden frames is still continued for the same description of buildings. The business of a glazier, if considered in its most simple operations, consists in fitting all the various kinds of glass manufactured and sold into sashes previously prepared to receive them. The sashes, as they are now made, have a groove or rebate formed on the back of their cross, and vertical bars adapted to receive the glass; into these rebates the glazier exactly fits the squares, which he beds in a composition called putty. The putty consists of pounded whiting beaten up with linseed oil, and so kneaded and worked together as to make a tough and tenacious cement, and is of great durability; this the glazier colours to suit the sashes he may have in hand; if they are common deal sashes, the putty is left and used as first manufactured; but if they are mahogany, it is coloured with ochre till it approaches more nearly that of the sashes.
In glazing windows the colour of the glass is that on which the greatest beauty is given to the work; and to effect this successfully, many different manufactories have been established. The most usual kind of window glass now employed by the glaziers is called crown glass; it is picked and divided at the manufactory into the several different kinds, which are known as first, seconds, and thirds, and which particularly denote the qualities of the several kinds of glass, the first being known as best crown, the next in quality second crown, and the last, thirds, or third crown, the price of each varying according to the quality. The glass is in pieces called tables, of about three feet in diameter each, and, when selected and picked as above, they are packed in crates, twelve of such tables being put in each crate of best glass, fifteen in the seconds, and eighteen in the thirds.
Green glass is another of these species, and which is greatly in demand for all the purposes in which colour is not so particularly sought for. This sort of glass is used in the glazing of the windows of cottages, also for green and hothouses, to which it is found to answer every purpose: it is not more than one-half the cost of the crown glass. The green glass appears to have been the most ancient kind made use of, as most of the vestiges remaining in the old windows approach very nearly in their quality to what is now sold under that designation. The glaziers also prepare the crown glass so as to produce an opaque effect, to prevent the inconvenience of being overlooked; it is technically called ground glass, which is not improper, inasmuch as it is rendered opaque by rubbing away the polish from off its surface, to do which the glazier takes care to have the sheets or panes of glass brought to their proper size; then they are laid down smoothly as well as firm, either on sand or any other substance which is adapted to admit of its lying securely; he then rubs it with sand and water, or emery, till the polish be completely removed; it is then washed, dried, and stopped into the window for which it was prepared.
There was a species of glass made at Venice originally, which was manufactured wholly for this purpose, and is now to be seen in many counting-houses and old buildings; its general appearance presented an uneven surface, appearing as though indented all over with wires, leaving the intervening shapes in the form of lozenges. This glass was very thick and strong, and is of the description known as plate glass; it is now, however, generally substituted by the ground crown glass. A very beautiful plate glass is manufactured by the British Plate-Glass Company, at Ravenscroft, in Lancashire, and at their depot in Albion-place, London, plates of every size, up to those of very great dimensions, may he obtained, the thickness varying from an eighth to a quarter of an inch. The cheapest kind of glazing is the old fashioned mode, in small squares of the diamond or rhombus shape, technically called quarries, which are fixed in rebated leaden bars in outbuildings, cottages and in some kind of church windows. The lead for this purpose is cast and drawn through an instrument called a glazier's vice, which gives it the exact form required, and perfects the grooves for the reception of the quarries. These leads being cut to the proper lengths, they are soldered together at the intersections.
This metal, which is used instead of the cross bars of sashes, is so soft as to be easily bent where the groove is left in it for the glass, and to be bent up again to inclose the glass after it is inserted. Window lights of this kind are further strengthened by vertical or horizontal bars of iron or wood, secured to them by bands of lead twisted around the bar. Glaziers now cut all their glass with a diamond; whereas, formerly, an instrument was made use of for the purpose, called a grozing-iron. The diamond used by glaziers is left in its natural state, or with its outward coat; when polished, it is said to lose its property, making a perfect fracture of the glass; it is fixed in lead, and secured by a ferrule in a handle of hard wood, and is used by drawing the diamond point over the glass, straight lines being effected by the assistance of a straight edge, also of hard wood. The other tools used by the glazier chiefly consist in "stopping-knives," for spreading the putty over the edges of the glass and rebates of the frames; in " hacking-out tools," which are strong-backed knives, capable of bearing the blows of a hammer, and used in clearing out the old putty, or making repairs; also in a pair of compasses, a three-foot rule, and a few other common tools, the uses of which require no explanation.
New sashes should always be primed, that is painted once over before they are glazed, as the putty thereby holds much more firmly to the work.