This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
Several species of glass are employed for this kind of glazing. Amongst these may be specified "sheet" and "plate" glass of various kinds; "coloured glass," either "pot-metal" or "flashed" ("pot-metal" being coloured throughout its substance by the addition of metallic oxide while the glass is in a state of fusion, while the " flashed " glass is white, with one surface covered by a thin film of coloured glass); "flashed" glass being made in ruby, blue, opal, green, violet, and pink. These colours can be also modified to red, orange, amber, and lemon colour by staining. Another species, called "cathedral glass" (rolled and sheet), is generally applied to light tints of a positive colour, and is principally used for glazing the windows of churches. " Antique " glass is made in various shades of colour, and is usually employed in figure work in stained-glass windows. It is an imitation of that which is found in old leaded lights, and is rough, nubbly, and of uneven thickness. It has recently been made with the colouring oxides encased, and also striped with various colours to produce a more striking effect in the fold of garments in figure work. "Aveuturine" is a glass made in slabs, and used occasionally in mosaic figure work.
It is generally of a brown semi-transparent colour, and has a peculiar striking effect, caused by the suspension of metallic particles, principally copper filings, which is the chief ingredient. "Ambilti" (single and double) is a sheet glass, originally of Italian manufacture, and much prized by glass painters on account of its softness for staining, and generally brilliant appearance. " Quarries " is the term applied to small square pieces of stained glass, such as are used in the borders of windows; and "roundels" and "bullions" are small discs of glass, some made with a knob in the centre, and used in fretwork with cathedral glass.
The Use of lead "calmes" for fixing window panes is of venerable antiquity, the employment of wooden sash-bars being quite a modern innovation. The calmes or leads for the fretwork are slips prepared in the tool known as the " glaziers' vice," wherein a slip of lead is drawn between 2 horizontal rollers of the thickness of a piece of glass, and the calme, as it emerges from the mill, has a section exactly like the letter I. The German vices are the best, and turn out a variety of lead of different sizes. There are moulds with these vices in which bars of lead of the proper sizes are easily cast. In this form the mill receives them, and turns them out with 2 sides parallel with each other, and about | in. broad, and a partition connecting the 2 sides together, about 1/8 in. wide, forming on each side a groove near 3/16 by 1/8 in. and 6 ft. long. At the present day most glaziers buy their calmes at the warehouse. The ancient calmes were apparently cast in a mould. Antique calmes are nearly of one uniform width, and much narrower in the " leaf " than modern leads.
That this was the case, can be proved not only by the existence of the original leads themselves, but more satisfactorily perhaps by the black lines drawn upon the glass, with which the glass painters were accustomed sometimes to produce the effect of leads without unnecessarily cutting the glass. The process of compressing the modern calmes between rollers to the proper dimensions makes them more rigid than the old leads.
The ordinary leaded casement is still to be found plentifully in cottage windows in the provinces. These are formed of every shape and size, some glazed with rectangular and some with diamond-shaped panes. The calmes in which these are set are often very broad in the leaf, much more so than could be used for fretwork. Glaziers differ as to the best tool for soldering the calmes, some adhering to the old soldering iron without a handle, while others prefer the ordinary copper bit (see Soldering, p. 108). The cutting knife, used for dividing the calmes, has sometimes the form shown at a, Fig 1364, and is sometimes shaped as at b. In the latter, the blade has its cutting edge at c, and the top of the handle d is usually formed of a lump of solder, which is handy for driving home the panes in the calmes, driving a brad or tack, etc. e is the "ladikin," which is a small tool of bone, box, or beech, about 6 in. long. 1 in. in width, and 3/8 in. thick, with one end bevelled off for about 1/2 in. as shown. This is used for opening the leaves of the calme as shown at f.
The first step in making a lead-light of square panes is to measure the opening and set out on a board or the work-bench in chalk the number of panes decided on; next the glass can be cut, not forgetting to allow for the thickness of the calme, and, this being done, proceed to put the casement together as shown, Fig. 1365.
Tack down to the bench a couple of laths at right angles as shown at a b, ac (Fig. 1366). Take a calme, and putting your foot on one end to hold it steady, stretch it out, by pulling, perfectly straight; now cut a piece of about the depth of the window and place it against the lath a b, as shown at d e, and secure it to the bench by a couple of brads as shown. Next cut another length of the calme the breadth of the casements; open the of the calme de with the ladikin, as shown at f, Fig. 1304, insert the end of the calme last cut in the one already fixed at d, taking care to see that this end is bright, and brad this second calme down, as at df, at right angles to the former, and along the lath a c. The calmes are cut with the cutting knife. The pane of glass 1 is now taken, the ends of the calmes de and d f opened out with the ladikin, the square of glass is placed in and tapped up home with the heavy handle of the cutting knife. Having set pane No. 1, cut with the knife a piece of calme of the exact length of the side of the square, taking care to see that the end is bright; open both sides with the ladikin, then place the end in the calme d f, as shown at g; pane 2 is now placed in this, and carefully tapped home with the handle of the knife; then the lead h is cut and placed; next follow pane 3, calme i and pane 4, etc, and the first row is glazed.
Take especial care that each pane has been knocked in home and that the whole row is tight. Now comes the cross calme I m. Stretch another calme and cut it to the proper length and open it up with the ladikin. Insert the end of this in the vertical calme d e, and place the ends of the spurs g h i k in it. Now begin another row with the pane 6, follow this with the short lead n; then the pane 7, lead o, pane 8, and till the second row is complete. When all the panes are fixed in and the casement is complete, the end calme is fixed, and then the side one r s. All is now ready for the soldering. The bit or soldering-iron is heated, and the operator takes a strip of fine solder, in his left hand, of an easily fusible kind. He then sprinkles a small quantity of black rosin at the place to be soldered, places the end of the solder strip to the first and applies the heated bit until a good joint is made, and the solder makes a neat little raised circle at the place. This operation is repeated at each joint until all are secured. Some workmen prefer "killed" spirits of salts (see p. 101) to rosin for the flux. The bit or iron should not be too hot, and should not be held in contact with the calmes too long. It is important that the ends of the lead be bright, or a good joint cannot be secured.
The bands which secured calmes a b d, b e to the brads must now be loosened, the light turned over, and the other side be soldered in a similar manner. Next the "bands" or "ties" have to be fixed. These are small strips of had or little bits of copper wire, intended to secure the lights to the "saddle-bars" of the window. The saddle-bars are horizontal bars of small iron rod crossing the window-opening, their ends being set in the stonework or wood, and are intended to support the glass. As many bands should be soldered on as the glazier deems requisite. Copper wire ties are generally preferred for fretwork. In the rectangular iron frame for opening Basements, to which the lead light is fitted, the smith generally drills small holes all round, and the glazier will require to solder his ties around the lead light at such places as will correspond with these holes and in such a manner that the ties stand up at right angles to the clame to which they are soldered. They must also be of such size that they will pass through the holes. These ties are put through the holes in the casement frame, cut off flush with the top surface of the iron.
A bead of solder is now dropped on the end of the tie, well spread with the bit, and finally pressed down into a nice flat round bottom by the sudden and momentary application of the thumb, well wetted with saliva.
The lead-light is now finished all but the " cementing." This process is adopted for several reasons. In the first place it helps to secure the glass in the lead-work, something as putty does in sash-windows, then it keeps the whole window watertight and windtight, etc. Proceed thus: - Take an old sash-tool and a little stiff lead-coloured paint, and rub the joints and calmes therewith. Then take a small blacklead brush and a small quantity of whiting, and with this brush rub the paint until it appears all brushed out of the crevices, brush off the whiting, and repeat the process with some lampblack, and brush away until the joints become as lustrous as if blackleaded. Finally clear off and clean the glass in the usual way.