In days gone by...Glazing

Home >> Glazing >>>

Cleaning Paintwork in days gone by.

Preparation and painting in days gone by.

Renewal in days gone by.

Signwriting in days gone by.

Paperhanging in days gone by.

Classic signwriting in days gone by.

GLAZING. In days gone by.

Sheet Glass.
The commonest and most useful glass, as far as the jobbing builder is concerned, is sheet, made by blowing the molten glass into cylinders 5 ft. or more in length, which are afterwards cut or split open and flattened on a kiln. Most of the sheet glass used is either Belgian or English. Generally the Belgian has a more greenish cast or colour than the home-made variety. Its different thicknesses are distinguished as 15, 21, 26, and 32 oz., the numbers indicating the approximate weight per foot.
Sheet glass is further divided and graded by selection namely, best, seconds, thirds, and fourths. The defects looked for are waviness and air bubbles. Air bubbles in sheet glass are elongated; in plate glass they are spherical. This is one of the simplest guides in determining whether a sample of glass is sheet or plate.
Sheet glass is usually purchased by the crate, made up of about 700 sup. ft.
The extreme dimensions of 15-oz. glass are: length, 55 in. ; width, 38 in.; of 21-oz.-length, 85 in.; width, 49 in.; and of 26-oz.-length, 85 in.; width, 49 in.
It is often convenient to purchase glass in cut sizes.
Obscured Glass.
Obscured or ground glass is the sheet glass obscured by sand blasting.
Fluted glass is often used where only partial shading or obstruction is required.
Enamelled sheet glass or embossed glass is also used for screening purposes.
Crown glass is now almost out of date. It was made in flat discs by a process of spinning. Thus all the waves are concentric, and the broken-off centre shows a knob or bulb, known as a bull's-eye. Crown glass in cutting up entailed a good deal of waste. Further, it was never particularly flat. It may generally be detected by its unusual thinness, and white colour. The bull's-eyes are to be seen in houses of the Queen Anne period. The windows also, by their irregular mode of glazing, placing some squares with the bowed side outside and others the reverse, are a sure indication that the glass is crown. To-day bull's-eyes are sought for by the connoisseur, and the architect who knows his business will not have repairs done to broken windows of the period with ordinary 15-oz. sheet glass. Bull's-eyes are in such demand that they are manufactured specially, and are imitated by casting. They have been responsible for fires in many cases by acting as a burning glass.
Roofing Glass.
Rough-cast and rough-rolled plate may be had in thicknesses from i to i in. There is practically no limit to size. These varieties are useful for roofs, and the thick glass may be used for walking on and carrying heavy weights.
Hartley's roll, 1 in., and Hartley's plate, i in. thick, are used on roofs. A most useful roof glass is wired plate, which,. even when fractured, will not drop to pieces.
Plate Glass. Polished plate is made from rough-cast plate by grinding and. polishing with various abrasives, including emery and rouge. It varies in thickness from 1/2 to i in. The most usual thickness is inch plate, the 1 being often called patent plate. Plate glass is made in tremendous sizes, as may be seen from some of the leading store windows. So far as furnituremaking goes, 1/4" plate is the favourite, but the trend for ordinary glazing tends more to the thin variety. Glass fascias are generally i in. thick. The less they are cut up the better, as the joins present an easy prey to moisture.
Rolled Glass.
Quite a number of useful varieties, all of them rolled, are known as figured rolled, oceanic, arctic, and stippolite. These may be had in white, that is, transparent, or in various tints.
Quite a number of useful glasses come under the head cathedral, which may be had in white or in tints. Flemish glass includes varieties of rolled glass of a wavy surface, made in white and tints.
Opalescent rolled glass provides broken-colour effects.
Opal Glass.
Opal glass is of two kinds-pot opal and flashed opal. Pot opal, as its name implies, is white all through, whereas flashed opal is really clear glass with a fired-on opal coating.
Pot opal is useful for sign purposes in connection with fluoric acid or the sand-blast. The surface of the opal may be engraved and filled up with paint in various colours, presenting a practically permanent sign.
Flashed Glass.
Flashed glass has a film of colour on one side only, generally ruby, blue, amber, green. The reason for this method of manufacture is to be found in the great colouring power of the oxide.
It should be possible to get all round the bench. Placing it with the wall behind and at one end is a mistake, even though it suggests space economy. Some prefer the bench tilted a little one way. but that is a detail. The bench should b~ larger -considerably larger-than the glass that is to be cut. If the general run is sheet glass, the size of the crate will be a good guide. Let the bench be as large as conveniently possible. Cover it all over with green baize or thin felt, bringing it over the edges and tacking it underneath. Afterwards screw a thin oak strip, I! in. wide, the length of the bench, one side only countersinking the screws. Use long squares, and have a place to hang them when not in use, so that they do not get knocked out of shape. Several long laths with a short piece screwed at each end are useful. The lath may be placed over the glass near the guide marks, and since it may be pulled close up to the edge of the glass, there is no fear of its slipping when pressure is brought against it with the diamond.
Glass Cutting.
For plate glass use a plate diamond; for sheet, a 21-oz. diamond will answer. The diamond should always be personal and not public property, since no two people will hold it alike. It is the angle at which a diamond is held which determines its cutting quality.
Several wheels are necessary for cutting intricate shapes and rough-surface glass. There are at least two good makes, and nothing is to be gained by trying to save pence on glass cutters. The glass firm will probably put the jobbing builder on the right tack.
A pair of wide-mouthed pliers, made specially for glaziers, should be handy for gripping narrow strips and breaking or pinching them off. An old well-worn rasp is often a handy tool for rough edges, as will be learned after the experience of a few deep flesh cuts.
It is advisable to use the sheet-glass diamond for clear sheet only. A good diamond, or rather a good cut, makes but little noise. Old-time glaziers used to say of a good diamond, "It sings," and, truth to tell, once the ear has become accustomed to the sound, it is easy to know whether a cut is a good one or not before attempting the" break."
A deep scratch is no good, going, in fact, no deeper than it looks.
When cutting sheet glass, keep the rounded side downwards. After breaking a few sheets by doing the reverse, this will, no doubt, be understood. For marking on glass use a piece of hard soap cut to a chisel point, or even a piece of chalk. For cutting sheets it is not a bad plan after the cut to bring the cut line along the wooden slip screwed to the bench. A slight jar with downward pressure will assist in a clean cut. For short pieces this is unnecessary. Sometimes tapping the glass directly underneath the cut, beginning at the edge nearest the glazier, will start the glass.
It may be necessary on occasion to tap the whole length of the cut, but do it gradually and gently.
When glazing sashes, "allow ^1/16 in. all round" is quoted as a rule, but so long as the glass is free, that is all that matters.
~Glazing Window-sashes.
Previous to glazing, all sashes should have at least one coat of paint. Bare wood absorbs the oil in the putty, and detracts from its life.
Use the putty quite soft, bed freely, since what putty is squeezed out behind may be used over again for bedding, and it is a ticklish job having to fill up afterwards.
The glass should be secured with short sprigs, and the front putty used stiffer.
A glazier who knows his business will be sparing with front putty, and keep the angle well within the rebate.
When the usual run of painters glaze a sash, the putty is brought beyond the rebate, so that it shows inside the room. So long as the edges of the glass are sealed, the angle is sufficient. Use brings the certainty of correct angle. What looks worse than putty in different angles on the same sash.
See that finger and putty marks are removed at the time of glazing. If a little dry powdered whiting is dusted on, the marks will come away quite easily; left to get hard, they will be a source of trouble, being scarcely amenable to turpentine. Putty is an important item in glazing. The usual specification stipulates best whiting and cold drawn linseed oil. Such a putty will always give satisfaction, but chalk and fish oil are anathema.
Glazing Repairs.
Repairs are often troublesome by reason of the frailty of the sash and the hardness of the putty. It is often easier to cut the wood than the putty.
Glass should be cut free, irregular parts being nipped off with the pliers.
Glazing Greenhouses and Garden Lights.
Greenhouses provide a deal of work for the glazier. If the glass is well bedded and sprigged, front putty is unnecessary. A lap of 1 to i in. seems sufficient. Glass on front of greenhouses may be butt-jointed, and if cut clean, will effectually resist the weather.
Cutting Plate Glass.
Plate glass often presents a problem to the jobbing builder. To watch glass-cutting at a large glassworks is an object lesson. It is all so easy, all so sure. Uncertainty would be ruinous.
For plate glass use a plate-glass dIamond, and ignore the fairy tales about the cutting properties of cheap wheels. After the cut, place a thin lath underneath extending the length of the cut and beyond, then lightly tap the' end near the glazier. Bring the cut level with the edge of the lath and apply pressure. If the cut is good, the glass will break along the diamond mark. The chief point to remember for long pieces of glass is that the thin lath should be longer than the glass, otherwise with the pressure the glass may break off diagonally from the end of the lath.
For short pieces, draw the glass over the front of the bench, and with slight taps start the break. Push the glass back on the bench, and place the end of thin lath under the cut. Apply slight pressure and the glass will break clean. Really once the knack is acquired, cutting plate is easier than cutting sheet.
Cutting Shaped Glass.
For shapes use a template made of i-in. plywood if a number of pieces of the same shape are required. If a single shape, mark it out with chalk on the green baize, and cut to it freehand. When cutting shapes it is advisable to cut the square first; there must of necessity be waste.
Cutting Rough-surface Glass.
Cast and rolled plate may be cut with a wheel or a diamond. Considering the hard usage, a good wheel for the jobbing builder seems the more useful. Cast plate, Hartley's roll, wired glassall are cut after the same fashion. Let the lath sail from end to end of glass as for ordinary plate.
Weather has an unsuspected effect on glass. Glass exposed to all kinds of weather, especially frosty weather, will defy safe cutting. Glass that is wet is also difficult. Of course, cutting is always done on the smooth side.
Glazing Roofs.
Glazing roofs of factories or doing glazing repairs are ticklish jobs. It is always more difficult to repair than to glaze. At one time a good deal of roof glazing was done with wooden bars, tar string, and screw-on wooden caps.
The weak point in this kind of glazing was the tar string, which in dry weather became hard and harsh, often twisted or formed into loops. By substituting rubber of the same diameter as the tar string, watertight roofs result.
Glazing Skylights.
Roof or flat lights are often troublesome. Being high up, the builder often takes the word of the operative as to their condition. There is nothing better calculated to set a customer on edge than a leaky roof, for a roof leaks when everybody is more or less a little below par. Further, it is next to impossible to deal successfully with leaky skylights in wet weather. Experience goes to prove that these parts of a building are the most neglected Many a skylight has been condemned as leaky when the fault has been condensation. Painters in an excess of zeal often seal up the bottom squares of glass on sky and flat roof lights with putty. Consequently condensed moisture cannot drain away, but has perforce to drip inside the building.
Glass on lantern and lay-lights is often cut short, not from economy, but ignorance; consequently the water, instead of draining oft, tails back and is drawn under the glass by capillarity. Glass should always sail an inch at least over the woodwork.
Wired Glass.
Owing to the danger of falling glass, lay-lights and roofs generally should, where possible, be glazed with wired glass.
Glass Subject to Jarring.
Glass in wooden partitions, or doors that are continually on the move, may be fitted with grooved rubber sheeting similar to that used round glass on motor-cars, being afterwards secured with beads. It will be found more serviceable and better in every way than using strips of chamois leather. In fact, ordinary window glazing, especially where the squares of glass are of a good size, could be done more expeditiously and be repaired more easily if glass were fixed this way with wooden beads instead of putty.
As a general rule, all slightly rough and rolled glass can be cut best with a wheel. These varieties are usually very brittle and require expert handling. Arctic glass is especially hard, though, being smooth, or comparatively so, on one side, the diamond is sometimes preferred to the wheel. Cutting wheels vary considerably in quality, and, once suited, it is advisable to stick to one make.
Glazing with Ground Glass.
Ground sheet glass, though not used so much as formerly, is a useful variety for many purposes. It is, of course, cut on the smooth side, and in glazing this side should be outwards, that is, exposed to the weather.
The edges of the ground side should be coated with weak size or gelatine, and be allowed to dry before glazing, otherwise the oil from the putty will run on the glass and show a practically transparent irregular border.
The size may be coated on an inch wide or more, as it may be removed quite easily afterwards with warm water.
Grinding or Frosting Glass.
At one time a good deal of glass was ground by hand on the bench. Plate glass, being level, is easier to manage than sheet. The glass to be ground should be laid flat on a bench, which should be covered with clean felt free from grit or particles of glass. Under pressure, if the glass moved, the surface could be readily marked.
For a grinding tool, use a piece of thick plate glass 6 in. by 4 in. This should be fixed to a piece of flat wood of convenient size with a handle, using melted resin to fix the glass. If the base of the wood is sunk slightly, the glass will be firmer. For grinding, wet the glass and use medium or fine emery powder. After a while use fine emery alone. Continue grinding until a matt of the required density is obtained. The movement during grinding should be circular, and when removing the rubbing block, slide it off one side of the glass, and do not attempt to move it by raising it bodily.
Cutting Opal Glass.
Opal glass is difficult to cut. See that the surface is not greasy. Generally a diamond is preferred to the wheel. Ground opal is a useful glass for many purposes, especially for lettering on. Using the ground side, a properly mixed varnish paint will last for years, while on smooth-surface opal it will not remain intact as many months.
Fixing Glass Tiles. Glass tiles are not always a success owing to faulty fixing. There can be no adhesive better than good linseed oil, putty and paste white lead in equal parts, to which a small percentage of quick japanner's gold size has been added. Failure follows the use of indifferent gold size. Some are no better than boiled linseed oil, whereas a good, quick japanner's gold size is a gum product, and will dry within forty minutes.
Tiles often come away because the ground is all wrong. The ground should possess little suction; a coat or more of paint provides an ideal grip for the adhesive.
When bedding glass tiles, the nature of the job is the best indication as to whether the adhesive should go all over the back or be applied to edges only. Clean up the face at the time of fixing, especially if japan gold size is incorporated in the adhesive, or it will be difficult to remove once it is dry.
Repairing Lead Lights.
Though lead glazing, which once flourished in country shops, has gone into the hands of the large manufacturers, there is always repairing to be done. The new type of glazing is more difficult than the old, owing to the slenderness of the lead. Some lead lights are so knocked about that nothing short of removal and repairing with new lead is of any use. For ordinary repairs, however, such drastic methods are unnecessary. Some glaziers cut the glass to shape before removing the broken parts, others remove the glass first.
Turn up the lead as far as possible, using a smooth or roundpointed knife. The difficulty is at the soldered joints, and often the glass has to be slightly rounded or nipped off with the pliers. Keep the glass as tight as possible, then smooth back the lead. Often a piece of lead-coloured putty is advisable to ensure that the job is perfectly weatherproof.
Cementing Lead Lights.
Lead lights are sometimes leaky owing to the cement deteriorating. To remedy, coat with boiled linseed oil to which a little red lead has been added. Use a mixture of dry powdered whiting and dry vegetable black, and brush it all over the light. This will combine with the oil, which, of course, must be brushed on only sparingly, and form a putty or cement. Clean up with dry wood ashes, using a flat brush or shoe-brush.
Glazing Swing Signs.
Unusual jobs sometimes come the way of the jobbing builder. Double-sided swing signs are sometimes broken during transit or glazing. This happens more frequently when the shape is unusual and complicated. There may be one point where the glass binds on the frame, and this but slightly, but on the least pressure the glass will break.
The glass is generally dropped on to a wooden backing, secured with zinc clips, and front puttied.
A smooth pad of cheap felt or other soft material should be behind the glass. The glass should drop in freely and be secured by sufficient clips to make the pressure uniform, while the putty used should be quite soft.
Glazing Glass Fascias.
Glass fascias are dropped, as it were, in a frame, and secured with mouldings or beads screwed into the frame. Putty is used to make the front watertight. The slightest miss in using the putty will be marked by the first heavy rain. Where the lengths of glass butt or meet is the weakest part in a fascia. The pieces are usually separated by a narrow wooden slip, and the joint is covered with a narrow bevelled strip of glass. If the wooden slip were sunk sufficiently to allow filling up the j oint with putty stained to the colour of the ground, and the superimposed slip were bedded at the same time, a more lasting fascia would result.
Fixing Glass Slips on Windows.
Long bevelled glass slips are sometimes fixed on shop windows. Hard or lumpy adhesive and uneven pressure will snap them. Whenever possible, make a groove at each end of the window or square, as this will add to the slip's security.
Bed edges only with equal parts ordinary putty and white lead. Clean up the edges at once, and to keep the glass in position stick gelatine jubes at intervals under the glass.
Cutting Mirror or Silvered Glass.
Mirror or silvered glass is generally supplied with a waterproof backing. Even so, where the glass has to be cut, the bench covering must be free from grit or the silvering may be damaged. Mirrors are best protected by having a thin wooden backing when placed against plastered walls.
Protection of Mirrors.
Glass mirrors placed in frames should always have their edges painted black or dark, otherwise they show an unsightly reflection; placed against walls, the dryness of which is doubtful, they should be coated with one of the waterproof bituminous paints.