The Handyman's Pocket Book: Glass and Glazing.

KINDS OF GLASS:  Glass is obtainable in various thicknesses and textures.  The more frequently used thicknesses vary from 18 0z. per square foot to 32 oz., 24 0z. being generally used for domestic windows.  Polished plate glass ranges from 1/8 in. to 2 in. thick; weights available are: 18, 24, 26, and 32 oz.  Sheet glass is not ground nor polished and shows a certain amount of distortion when looked through, though the modern drawn method of production is very good.  Plate glass is polished and ground on both faces, providing a clear, true surface without distortion.

Fancy glasses, mostly of the cast-plate type, are obtainable and about 3/16 in. in thickness.  Among the varieties are, Hammered plate, Muranese, Cathedral, Hartley's Rolled plate, Muffled sheet, and Cast wired plate, the last being suitable for fanlights or lay lights where a breaking window can be dangerous in falling.  This glass is composed of two sheets of glass with a metal wire mesh between and the whole fused together forming a plate about 1 in. in thickness.

GLAZING.  When glazing a sash or window remove all old putties with a hacking-knife, and clean the rebates of all projections that may interfere with making an even bed.  Paint in the rebates to provide a key for the putty.  The glass should be measured and cut accurately with about 1/16 in. clearance only.  Work the putty in the hands until it is soft, and taking a small ball in the hand, thumb in a thin bed around the rebate (A, Fig. 1).  Place the glass, and carefully press down to a fair seating in the putty (B).  Drive in a few sprigs to secure the glass and then thumb in the retaining fillet of putty and finish off with the knife to an even face (C).  The main point in glazing is to seat the glass on an even bed without forcing or distorting, even when wood glazing beads are used it is desirable to bed the glass in putty.

In some classes of work such as car work and ship joinery, a rubber or velvet fillet is used in place of putty.  By this method a certain amount of creep is allowed without injury to the glass.  In furniture glazing, glasses are often bevelled at the edges.  In this case care must be taken to regulate the glass in the rebates so that the mitres intersect with the frame, particularly in the case of silvered mirrors.

MIRRORS.  The surface of the glass beneath the rebate, also the rebate, should be blacked with spirit black to prevent reflections.  When dealing with silvered mirrors care must be taken not to damage the backing, as once damaged the silvering is impaired, and the only remedy is resilvering.  Old mirrors can be cleaned off and resilvered when they are as good as new again.

Mirrors are fixed in position by small wedge-shaped wood fillets fitted in the rebate space between glass.  These wedges are glued to the frame.  Lay the frame on the bench face downwards and see that it is free of winding - a heavy frame may easily drop out of truth by its own weight.  Place the mirror in the rebate, making sure that it has the same margin all round (a mirror should be about 3/16 in. short all round).  Glue in the wedge pieces so that the sloping surfaces catch the edge of the mirror.  They can be fixed every 6 in. or so, and should not be disturbed until the glue has set.  Fig. 2 shows the process.  It is a good plan also to bevel the top of the wedge so that a pin can be knocked in.  It will then hold even in a damp atmosphere.  For bevelled mirrors it is advisable to work to the right size and add on the rebate overlap rather than work to the rebate.  Note that internal mitres are always more expensive than external ones.

LEADED LIGHTS.  If a single pane is broken the old glass should be removed with pincers, and a cut made at each corner on one side as at A, Fig. 3.  The lead can then be bent outwards as at B, a thin wooden tool shaped like C being used.  The new glass is cut an easy fit because it is almost impossible to turn the lead back to the bottom of the groove.  Put a small bed of sealing compound such as Seelastik in the lead, press in the glass, and turn back the lead.  Preferably the corners should be re-soldered but it is not always essential.  If it is done, scrape the lead clean and use tallow as a flux.