Hand-blown Domestic Glassware 03

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Hand-blown Domestic Glassware 30 1947

5. Production


The industry employs for the most part a lead-potash glass, the general formula of which was discovered by Ravenscroft in England in the seventeenth century. The glass is obtained by melting in closed pots, in a furnace, a mixture of sand, red lead, potassium carbonate, cullet or broken glass scrap and small quantities of other materials included for special purposes such as decolourising, colouring or improving melting conditions. A typical batch composition is 100 parts by weight of sand, 66 parts red lead, 33 parts potassium carbonate normally melted with 100 to 150 parts of cullet. The lead-potash glass is characterised by its softness or slow setting, and by its brilliant appearance, which is much enhanced by cutting. Its slow setting properties make it suitable for working to shape by hand, though it is less well adapted to quick hand manufacture and to machine working than soda-lime glass.

To a comparatively small extent the industry uses soda-lime glass, the type of glass which is in general use for all normal purposes, e.g., the manufacture of flat glass, glass containers and common domestic glassware. This glass is produced by melting together sand, limestone and soda ash with small amounts of other materials added for special purposes.


Sand. The sand used has to be of a high degree of purity. The impurities which are specially objectionable are those, such as iron and chromium, which impart colour to the glass. To some extent the colour due to the presence of iron can be neutralised by the use of decolourisers such as nickel oxide and manganese dioxide, but the aim of the glassmaker is to start with a very pure sand. The iron content should be below 0.02 per cent. The grain-size, also, is important, under and over-size grains being equally undesirable.

Before the war the industry used a very pure and uniform sand, mainly obtained from Fontainebleau, France. Dutch and German sands were beginning to replace the French, being cheaper and generally better. When these sources of supply were cut off during the war, a satisfactory alternative source was discovered at Loch Aline, Scotland, which enabled the quality of the glass to be reasonably well maintained. First quality Loch Aline sand is considered to be at least equal to the best continental sands.

Manufacturers are conscious of the advantages which would be derived from the existence of a home source of cheap, high quality sand, and are, therefore; following with interest the efforts which are being made to market a sand of the highest quality from Loch Aline.

Red Lead. This material is manufactured in this country from imported lead. Supplies have been difficult since the war, but the industry has been fortunate in being allocated all its needs. Red lead is one of the more expensive ingredients and accounts for some 70 per cent. of the total cost of the batch. As the industry steps up its output the demand for red lead will go up correspondingly; we trust that adequate supplies will be assured by the Government Departments concerned.

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Potassium Carbonate. We have to depend on imports for all our requirements of the raw material from which potassium carbonate is made, but supplies of the carbonate to the glass industry have been maintained even during the war, when the usual sources on the Continent were cut off.

The supply position of this essential ingredient has now very seriously deteriorated, and there is a risk of production of lead glass being considerably reduced, if not actually stopped, unless adequate supplies are forthcoming in the immediate future. We would strongly urge the Raw Materials Depart­ment of the Board of Trade to see that present and future supplies are maintained at a satisfactory level.


The factories in this industry vary greatly in age, construction and condition. The nature of the existing buildings and sites have in some instances proved obstacles to modernisation in accordance with up-to-date practice.

In certain cases, plans for improvement were drawn up before the outbreak of war, but could not be carried into effect because of lack of building materials and labour. Experience during the war years has indicated that many of these plans are now capable of further improvement, and this has been confirmed by visits abroad. The plans are accordingly being modified so as to ensure that in general construction and lay-out the new British factories shall not be surpassed by any in Europe or America. We indicate (Plate overleaf) a simple glasshouse lay-out, prepared at our request by a British designer of glass factories, that typifies accepted current practice.

As shown, the glasshouse unit is compactly arranged on two floors, giving the advantage of reduced ground area and avoiding costly excavations for the lower part of the furnaces. The glasshouse shown is lofty and well ventilated and should, therefore, provide comfortable working conditions; the batch mixing room is beneath, in a position suitable for receiving raw materials and for transferring the mixed batch to the furnaces by the shortest route.

In place of the multi-pot furnaces hitherto employed, single-pot furnaces are shown, thus permitting the chairs to be disposed more conveniently in relation to the annealing ovens or lehrs. Another advantage is that the single-pot furnaces would avoid the need for pot arches, i.e., auxiliary furnaces used for heating up the new pots before introducing them into the furnace. The lay-out is elastic as regards size, in that the eight single-pots units shown in the plan could be easily increased to ten, twelve or more, and as regards method of melting the pot furnaces could be replaced by small tanks.

The lehrs have extensions which serve the chairs, reducing the work of the takers-in, i.e., boys who carry the ware to the lehrs. The extensions are kept warm so as to avoid breakage of the glass before it enters the annealing stage proper. Two lehrs are shown, since light articles such as stemmed wine glasses are usually being made at the same time as heavier ware, such as jugs and salad bowls, and it is useful and economical to have available two or more independent annealing schedules.


In many factories, as they are arranged at present, the location of these operations and the methods employed are capable of considerable improvement.

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Consideration is being given to the installation of facilities for mechanical handling, optimum conditions of storage, accurate weighing and efficient mixing of ingredients. If proper conditions of storage are not provided, powdered ingredients agglomerate into hard lumps which must be re-ground; and, in addition, if moisture is absorbed from the atmosphere, the blending of the ingredients becomes inexact. Apart from this, it is only by providing good conditions of work that contamination can be avoided. Quite a small trace of iron will spoil the quality of the glass. The need for the greatest accuracy of weighing cannot be stressed too much; the weighing should be accurate to 1 part in 1,000 wherever possible. Variations give rise to differences in melting rates, in the viscosity of the molten glass and in refractive index, with the result that streaky, non-homogeneous glass is produced. The materials must be very thoroughly mixed, especially when a particular mix is used to fill more than one pot.

The Factory Inspectors, who attended one of our meetings, stressed the dangers of silicosis and lead poisoning amongst the batch mixers (who form an extremely small proportion of the workers), but such cases are extremely rare. Nevertheless, all dust should be removed at the source by means of localised exhausts. The industry, management and workers, have meanwhile collaborated with the Factory Inspectorate on the task of devising the best methods of dust extraction, and suitable plant is now being installed.


A batch, even when thoroughly mixed, can become “de-mixed” if subjected to vibration. The shorter the journey from the mixing house to the furnace the better. In some instances the distance is too great, floors are uneven and the wheels of the barrow have to pass over broken glass on the floor. One well-known method of preventing de-mixing is to moisten the batch with 2-4 per cent. of water during the last stages of mixing. Efforts are being made to render the transport smoother either by siting the mixing-room better, by attention to the floors, or by the use of overhead runways.

The batch is melted in covered pots, which are set inside the furnace with their mouths projecting through the furnace walls. The batch is usually thrown on in shovelfuls, a practice at which the men become very skilful. Schemes to do this work mechanically are at present being examined, but it is realised that the problem is difficult. In view of the possibility of melting in tanks instead of in pots (to be referred to later), it would seem that any expenditure here should be postponed pending the results of experiments now in progress.


The furnaces at present used are circular in plan and take 6 to 12 pots each, usually of about 15 cwt. capacity. The pots are evenly spaced round the periphery with their mouths projecting outwards through the filling and working holes in the furnace wall. Most of the furnaces are fired by gas, usually raw producer gas generated on the spot. The gas is mixed with pre­heated air coming up through a central hole in the bottom of the furnace and is drawn out through ports in the furnace pillars between the pots, so that the flames play over and around the pots. Recuperators are provided to pre-heat the air.

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{Glass-Study: text from drawing. Drawing reference code: 1054.3181.C.6506.4M.11/47. (Ty.P.) original was a fold out insert, layout changed here to give clearer image.}

Layout of Glass House for the Manufacture of Finest Hand Made Crystal Glass Ware with Single Unit Furnaces.

Cross section: Glass House, Batch Mixing.

Longitudinal Section: Batch Mixing, Lehr, Discharge of Raw Materials & Loading Bay, Warehouse, Continuous Conveyor, Additional Loading Platform.

Sectional Plan: Chimney: Single Unit Pot Furnaces & Auxiliary Equipment, Lift, Pot Furnace (2), Glass House, Lehr (2), Single Unit Pot Furnaces & Auxiliary Equipment, Lift, Continuous Conveyor, Glass Processing, Glass Processing, Continuous Conveyor.

Hand-blown Domestic Glassware 33 1947

For melting, the furnaces are brought up to a temperature of 1,350° to 1,450° C, according to the type of glass being produced. When well melted the glass is reduced to a lower temperature, to bring it to the correct consistency for gathering and working.

The thermal efficiency of the present type of furnace itself is low. The efficiency in terms of fuel used in relation to glass melted and worked depends also on the way in which the furnaces are operated. There is a wide divergence between factories in the number of melts per pot per week, depending largely on the size and style of ware being made, and the number and skill of the operatives available.

There seem to be good grounds for believing that a greater efficiency would result from the replacement of the multi-pot furnace by smaller units, thus giving more economical firing, better temperature control of individual melts, and reduced idle time of pots. Investigations to which we attach great importance are now being made into the practicability of melting in open pots in small furnaces or in small tank furnaces working continuously or discontinuously.

The merits of the various types of fuel have been fully considered. Provided a reasonable tariff and supply could be obtained, the best fuel is town’s or coke-oven gas. Fuel oil is satisfactory, so is “raw” producer gas, though neither is considered suitable if open pots or tanks are used for melting, because of the danger of contaminating the glass with impurities from the fuel itself.


There are three major ways in which glassware is fabricated, and these may be referred to as (a) the hand-made or off-hand method, (b) the so-called mould-blown method, and (c) the “new process” method.

These methods are carried out by a team of men known as a chair, of which there are many variations, a typical one being described below.

In the offhand method (a), an operator known as the blower inserts a steel pipe, the blowing iron, which is about 42 in. long and about Ÿ in. diameter, into the furnace and, by rotation, gathers sufficient glass on its end. He forms the glass into a shape suitable for blowing by rolling it on a metal plate known as the marver, then blows down the pipe, and elongates the glass by swinging, so that the blown or hollow part of the article begins to take its intended shape. The final shaping of this part is done by further blowing and rubbing down with tools.

At this stage, the next worker, known as the servitor, takes over the blowing iron with the attached glass. Further glass is now added by casting on from an iron rod which carries glass obtained from the furnace by a gatherer, who is generally a less skilled worker. This further glass is then formed with tools to make a stem or foot as is necessary. The hollow (blown) bowl part, with such stem or foot, is then severed from the blowing iron by localised chilling and picked up by a rod or “pontil,” or a “gadget” (a device of steel claws) applied to the base of the article.

The final stage of the operation is then undertaken by the workman or gaffer, who re-heats the open end of the glass in a small auxiliary furnace known as a glory-hole, so that the waste glass may be cut off by shears. By further re-heating and the use of tools, this open end is shaped and finished. If a handle has to be

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added, or a lip has to be made as on a jug, it is done by the workman at this stage. The article is then separated from the pontil or gadget, and carried away to be annealed.

In the mould-blowing method (b), the blower carries out his part of the process by extending the blown part of the glass to the final shape by blowing it up in a mould, whilst rotating the pipe and consequently the glass thereon. This mould, which is usually of cast iron, is coated internally with a carbon deposit obtained by firing a carbonaceous paste on it, and is known as a paste mould.

In the “new process” method (c), the article may be finished off by removing the waste glass at the top by cracking-off, and then grinding and remelting the top edge, instead of going through the hand shearing operation.

Generally, a superior finish is obtained by the offhand method, but the rate of production is generally slower than by the “new process.”

No one who has seen glassmakers at work in our factories can fail to be impressed by the craftsmanship they display and by the speed at which they work. It is difficult, if not impossible, to compare output per man-hour or per chair-hour in this country with corresponding production in other countries owing to the difference in constitution of the chairs and other factors, such as the type of glass worked. With the present constitution of chairs, the rate of production per person employed is substantially the same in this country as in Sweden or America. In both these countries, however, the chairs include a larger number of the less skilled workers, and the heads of the chairs carry out only those operations requiring the highest degree of skill. As a result there is more economy in the use of skilled men and a greater efficiency of production.

It must be pointed out, however, that the worker’s week in Sweden and on the Continent, in general, is 48 hours as against about 37œ nominal and 34 actual here. In the U.S.A., the worker’s week is 40 hours nominal. As labour costs in this country account for about 50 per cent. of total cost, it is clear that every effort will be required to step up our production per man-year if we are to compete with foreign producers on level terms. There are two ways in which we can do this, (a) by securing improved efficiency in hand-making and by reconstitution of chairs, and (b) by replacing hand operations by such mechanical processes as give equally good results.

Productivity per man-hour depends on the skill and energy of each operator, but most of all on the way in which the individuals work together as a team. Hence, we consider that a careful study of the constitution and functioning of the chair is of the highest importance in order to ensure that each man works, with the minimum of idle time, at work which is at the highest level of which he is capable. Arrangements should be made to ensure that each man is supplied with the right material in the right quantity at the right moment, so that the minimum of effort is entailed in his obtaining it.

The extent to which hand operations can be mechanised without a deteriora­tion in quality is uncertain. Great advances have been made in mechanical production, and the difference between the hand and machine-made article is being steadily reduced

British lead crystal glassware is essentially a craft product having a world­wide reputation for the high quality of its glass, design, fabrication, and decoration. The whole range of its output is made to-day in very much the same way as for hundreds of years past, little change having taken place apart

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from improvements in the design of furnaces and lehrs and a great advance in the chemistry of glass. The introduction of the “mechanical boy” in mould blowing (a device enabling the blower himself to open and close the mould) is of the nature of a mechanical aid, but machines which replace the blower himself have not yet been introduced in this class of production, either here or, so far as we know, on the Continent.

It was one of the principal objects of the mission we sent to the United States to ascertain to what extent the hand factories there had succeeded in mechanising production. Although semi-automatic machines designed to replace hand blowing were seen and heard of, results being said to be good, only one such machine was seen in action. The majority of the factories relied still on hand blowing. The American factories have, however, developed the use of hand pressing as an auxiliary to or as a substitute for hand blowing.


A striking instance of how this has been done to the great gain of output is seen in the production in American factories of half-crystal stemware with a pressed stem, the bowl and foot being hand-made. In what is known as the “Moundsville” method, an eleven-man chair is employed. The glass for the bowl is hand-gathered and is blown in a paste mould by the blower. The bowl is detached from the blowing iron and fitted upside down in a hand press where the stem, the material for which is hand-gathered from the pot, is pressed on to it from above. The foot is then added by hand in the normal way. The output of the chair was said to be as high as 350 champagne glasses per hour. The blower was timed blowing five to six bowls per minute. The chair is much larger than the largest employed here, but consists mainly of less skilled men and girls. The wine glasses produced were of excellent quality. The stem inevitably showed mould marks, but these were largely eliminated by fire polishing and could, of course, be removed by suitable cutting of the stem.

Serious consideration should, we think, be given to the introduction of the pressed stem process into our factories to supplement, not to replace, our present methods. It would enable the output of stemware, of which we are so short, to be expanded considerably, using a few only of our limited supply of skilled men helped by less skilled workers.


The mechanisation of the manufacture of stemware would be carried a stage further by blowing the bowl mechanically and pressing on both stem and foot. This has been done on completely automatic lines in the Libbey processes developed by the Libbey Division of the Owens-Illinois Glass Co., Toledo, U.S.A. This process, even if the rights to use it were available, would not be suitable for adoption by the hand-blown section of the industry. This is not to say that automatic methods may not find application even by the hand-blown section of the industry, particularly if high quality glassware were to be produced along restricted lines only. It is possible, however, to envisage mechanisation applied in lesser degree, using semi-automatic machines for blowing the bowl, and hand presses for pressing on the stem and foot. Ware of a quality inter­mediate between that turned out by hand and by the fully automatic processes

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should be obtained. Such ware would find a ready demand from railway and steamship companies, hotels and other caterers, who usually purchase goods of an intermediate quality, previously largely imported from the Continent.

A number of semi-automatic paste-mould machines have been developed in the United States in which the glass is hand-gathered on a blowing iron and, after having been marvered, is then inserted by the gatherer in the machine for the blowing up, and the blown article is removed by a taker-in, who knocks it off the pipe for insertion into the lehr. We consider that the possibilities of these machines should be thoroughly investigated by the industry with a view to deciding whether any of them will give results sufficiently good to enable them to be used for making stemware in half or full crystal. It would be still better to have a suitable semi-automatic machine designed and made by one of our own glass machinery manufacturers. The design and manufacture of the hand presses for pressing the stem and foot on to the bowl should present little difficulty to our machinery firms, as hand presses are quite well known and commonly used in this country.


The introduction of semi-automatic blowing machines into the factory would also’ allow the semi-automatic production of tumblers and many other articles besides stemware, thus enabling skilled workers to be transferred to the production of articles in which a higher degree of craftsmanship is demanded.


In the American hand factories one does not find the complete divorce between blown and pressed ware production that has hitherto existed in this country. There, both types of articles are made in the same factory from the same glass; decoration by cutting and other processes is applied to both. In this country decoration is reserved mainly for blown ware. The American manufacturer can thus offer his customers a much wider range of articles, decorated suites being extended to include pressed articles.

In the technique of making hand-pressed ware, the American industry seems considerably in advance of ours. In the actual pressing itself there is not much difference to record. Great attention, however, is paid to the hand finishing of the pressed article to eliminate mould marks and give a better surface, and also to obtain a greater variety of shapes. The article after removal from the press is attached to an iron post or pontil by which it is held whilst being re-heated in the glory-hole. During the subsequent hand finishing, which is carried out on the same principle as for blown ware, a different type of tool is used. Manipulation of pressed articles to convert them into other articles, e.g., a vase to a deep bowl or a shallow bowl, or a dish, is also practised extensively.

We are of the opinion that the industry could and should widen the scope of its activities by taking up hand pressing and the manipulation of pressed ware on the same lines as in the American hand factories. It should be possible to make the pressed goods with a higher proportion of less skilled labour than is needed for blown ware. Pressers can be trained in a much shorter time than blowers, and only for hand finishing need it be necessary to call on the services of any of the skilled workers in the hand section.

The suggestion that the hand-blown section of the industry should take up pressing of glassware may be received with some feeling of apprehension by the

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hand pressed section of the industry here. We do not, however, believe that there is any need to fear any competition arising between the two sections. The hand-blown industry caters for a different market, producing goods of high quality in lead crystal, a considerable proportion of which is hand decorated, whilst the hand pressed industry confines its activities, for the most part, to the production from soda-lime glass of much cheaper goods without any applied decoration. The hand pressed and decorated lead crystal ware would, we consider, be creating a new market and not entering an existing one.


We recommend the introduction of mechanical processes so far as it is practicable to replace or supplement hand production in the existing factories, and also (see Chapter 8) the setting up of a new factory co-operatively run and equipped for semi-automatic production. Some reference is therefore necessary to the possibility of obtaining in this country the machinery and plant which will be needed if these recommendations are to be carried into effect.

Ancillary equipment including lehrs, conveyors, cracking-off, grinding and edge-melting machines used in our factories, is mostly derived from home sources. Glass-forming machinery, on the other hand, which, particularly in the container industry, forms the most expensive item in the equipment of semi or fully automatic glass factories, has hitherto largely been imported, principally from the United States and Canada.

It is obviously desirable that we should aim at becoming less dependent on foreign sources of glass machinery, especially when embarking on new mechanical production involving the design and manufacture of new types of machines. There are only a few firms, all of them relatively small, making glass-forming machinery in this country. Some of these, however, should, with the help and encouragement of the industry, be quite capable of providing the equipment which will be required.

The design, production and development of an entirely new type of automatic glass-forming machine of a kind which is likely to prove of use to this section of the glass industry might cost anything up to £10,000 or £20,000. None of the firms making glass-forming machinery in this country is in a position to spend this sum of money on developing such a machine, particularly since the prospect of large sales is slight. Considerable financial support would, therefore, be necessary for such a project; but progress step by step through various stages of mechanisation would, however, appear to be inevitable.

To avoid delay, consideration should, as an interim measure only, be given to the importation and adaptation of suitable machinery from the United States. Our delegation to that country saw several types of machines which should be of interest in this direction. Arrangements should, if possible, be made with the American manufacturers to have these machines built here, but failing this, machines could be imported for trial and use, pending the develop­ment of British types.


The old method of ventilation relied on the stack through which the furnace gases were withdrawn, but to-day temperatures in the glasshouse are kept down

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by means of canopies over the furnaces, and louvre or Robertson ventilators in or near the roof. For the best conditions, a large volume of air has to enter and leave the glasshouse at low velocity so that the workers are subjected neither to excessive heat nor to draughts, which last, too, are apt to raise dust to the detriment of the ware. The Americans obtain good ventilation and cool working conditions by building their glasshouses loftier than ours, enclosing a much greater volume of air, and by feeding air from trunk lines around the furnaces on to the ware and the workers.

To screen the workers from the heat radiating from the working holes in the furnaces, various devices have been employed, including asbestos curtains or sheeting and hanging chains. Fans to circulate the air have also been tried with some success.

A report upon tests on ventilation carried out in several glasshouses by H.M. Factory Inspectorate at our request is included in Appendix (E) below. Consultations between the manufacturers and ventilation engineers are being arranged to examine as thoroughly as possible, by heat balance investigation, the extent of the ventilation equipment which these tests indicate is required, and experiments are to be made to determine the effectiveness of this equipment. It is hoped that as a result of these investigations it will be found possible greatly to improve working conditions in the glasshouse.


(a) ANNEALING. The finished article, when it leaves the hands of the glass-maker, is in a state of strain, which, if not relieved, may result in its breaking spontaneously. To remove this condition the ware is heated to a temperature close to but below the softening temperature in an oven known as a lehr. The older types of annealing ovens were intermittent in operation, the ware being inserted in the oven in which it was heated to the temperature required, then allowed to cool, and finally removed. Some of our factories still employ an intermittent type of lehr, but in most the continuous type is used in which the ware is carried on a slowly moving endless belt conveyor, through a tunnel in which it is gradually heated up to the required temperature and then cooled according to an appropriate schedule.

The continuously operating lehrs have many advantages over the discontinuous type. They deal with a large volume of ware at a time, are cheaper to run and more economical in fuel. They provide for precise control of the annealing operation and they allow a flow production line to be introduced into the factory. A limitation is that all the ware in any one lehr is subjected to the same annealing schedule, which has to be set according to the requirements of the largest and thickest articles; the smaller and lighter articles are accordingly subjected to longer treatment than is necessary, though they are not thereby affected adversely. These limitations can be avoided by installing two or more continuous lehrs, or by having two belts which can be run at different speeds through a single lehr so as to have available alternative annealing schedules.

(b) INSPECTION. The best place for inspecting the goods is at the back or delivery end of the lehr. Sometimes inspection takes place at another point, involving extra handling and transportation of expensive articles easily damaged; this should be avoided. The use of fluorescent lighting at the point of inspection

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is recommended where good natural lighting is not available, and is, indeed, already being used.

(c) STORAGE OF BLANKS. Since single-line flow of manufacture has not yet been found possible, some ware requiring no decoration, some a little, and some still more elaborate decoration, the question of storage of blanks is of great importance. The lifting, transporting and laying down of the ware is not only costly but involves the risk of breakage at each handling. It is therefore recommended that wherever practicable arrangements should be made whereby goods sold plain should be packed direct from the back of the lehr, and the packages then sent by conveyor or truck direct to the warehouse.

Further attention should be directed to modern storage facilities which provide cupboards or bins fitted with shelves and easy of access. It is too often forgotten that the height of a building can be utilised as well as its length and breadth. Storage at ground or table level only is not the most economical.

(d) FIRE POLISHING. In this process, which is extensively used in America for treating mechanically produced goods, the ware is rotated in a hot flame to melt the surface slightly and to remove mould marks and other irregularities. A highly glazed, smooth, attractive surface is obtained. In the machines used for this purpose in America the articles are carried on rotating supports on an endless conveyor through banks of gas burners and air coolers.

The machines in general use are of considerable size, having to deal with large outputs, but smaller machines are available. We consider it urgent that attention should be given to the question of introducing this process here, especially for application to pressed ware.

(e) EDGE FINISHING. In the larger factories in the United States, the waste glass or “moil” at the top of the blown article (i.e., at the end where it has been attached to the blowing iron) is removed by burning it off by gas burner flames — a practice already in use in this country. A beaded edge results and it has been represented to the American public as an “improvement,” with a claim that this edge is stronger than the usual type.

So far as our American mission could discover, the attempts which are being made to devise a machine which will burn off the moil without producing a thickened edge have so far been unsuccessful. The development of such a machine would be of great assistance to the industry, since it would enable one process to replace the four which are at present necessary, viz., scoring, cracking-off, grinding and edge melting. We recommend this problem to the earnest attention of our technologists and machinery designers, and suggest that American efforts to solve it be closely followed.

The usual manner in which the moil is detached and the edge finished in this country is by scoring the article on an horizontal table by a tool fixed at the correct height above the table. The moil is cracked-off by placing the article on a rotating head with a line of gas jets directed on the scoring. The edge is then ground in machines in which the article is held against a rotating abrasive wheel. Finally the edge is melted to give a smooth even glazed finish by placing it on a rotating head on a multi-head machine in which it is passed through a line of gas jets for edge melting and another line of jets for annealing.

These processes, although carried out by simple machinery and operated by girl labour, add inevitably to the cost of production and take up a considerable amount of space in the factory, but with certain articles produced by the industry it may not be possible to eliminate them entirely. The development of a machine

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which will give an edge showing no thickening by a simple burning-off operation is a matter that deserves attention.

(f) DECORATING. The principal methods used in the decoration of domestic glassware are cutting, engraving, intaglio, etching, sand blasting and enamelling. The decorating in our hand-blown factories is now confined almost entirely to cutting, with some engraving and intaglio. In the United States, the method principally used is etching, and in Sweden, engraving, though some cutting is being done in America, and cutting is being revived to a considerable extent in Sweden.


(A) CUTTING. The blanks are first marked, generally only roughly, to indicate the pattern, which is then cut by holding the article against a revolving abrasive wheel. A V-edged wheel is used for mitre cutting and a flat-faced wheel for fluting. The work is done freehand by the operator. The cutting is generally in two stages, wheels of finer grade being used for smoothing and finishing the cuts preparatory to acid polishing. Overheating of the glass is prevented by directing a stream of water over the cutting edges of the wheel and on to the cut surface of the glass.

In the older type of decorating shops the grinding machines are simple in design, with overhead belt drives and with wooden bearings for the grinding wheel spindles. They are easily manipulated and adjusted when a change of wheel is necessary. More elaborate modern types are also in use in which each machine is separately driven by its own electric motor and has ball or roller bearings. A line of the new machines makes an attractive lay-out, but some doubt has been expressed about whether the penetration of water and abrasives into the bearings can be prevented.

A shallow or lighter type of cutting known as intaglio is carried out by a single cutting, only using fine wheels which produce a fine matt finish.

The mechanisation of the cutting process has been successfully ac­complished, and machines, a battery of which is installed in one of the Stourbridge works, have been developed in Germany for mitre cutting eight blanks at a time with straight line standard patterns. These machines are excellently adapted for the decoration of mass-produced lines. They enable cut-glass with standard patterns to be produced at prices which are competitive with low-priced foreign imports.

(B) ENGRAVING. Small rotating copper wheels fed with an abrasive held in suspension in a liquid are used for engraving and, as in cutting, the work is freehand. Engraving lends itself to a wider range of decoration than cutting and demands a higher skill. Figures, scenes and lined patterns are produced by it; the work may be left in the matt state and not polished. The industry should not neglect this form of decoration.

(C) ETCHING. Before the war some etching was done in our factories, but it has not been resumed. It seems doubtful whether it will be taken up again except perhaps for cheaper ware. In our opinion, the industry will be better advised to concentrate mainly on other forms of decoration in which skilled hand work is required.

(D) SAND BLASTING. This process has not been widely adopted for lead crystal ware in this country, nor do we see any reason to recommend its development on any large scale in the near future. It is used to a limited extent in the United States.

(E) ENAMELLING. Decoration by application of soft coloured glazes, which

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are subsequently fired on, is employed to some extent. The enamels may be applied by transfer, by hand painting or by the silk screen process. Paints are available for applying reflecting rings or patterns of gold or other metals. Much greater use might be made of this process, which offers a wide scope for highly artistic work.

(g) POLISHING. The final process is polishing, which formerly was done by means of circular brushes or soft wood wheels loaded with fine polishing powder. It is now done almost entirely by immersing the article in a bath consisting of a mixture of concentrated hydrofluoric and sulphuric acids. The bath dissolves a small amount of glass from the surface, giving a smooth, polished finish. This process obviates the risk of lead poisoning, but involves that of the acid burning the hands of the operatives. The operatives wear protective rubber clothing and, with hands covered by rubber gloves, dip the ware into the strong acid baths. After the appropriate time, the ware is removed and dipped into water to wash off the acid. Some progress has been made in the mechanisation of this process, and it is recommended that further attention should be given to its development.

TRANSPORTATION OF THE WARE WITHIN THE FACTORY. Reference has already been made to the difficulties under which the industry has been and to some extent is still working. Old unsuitable buildings offer a major obstacle to modernisation, and restricted sites have resulted in cramped conditions of work and have made modernisation difficult. Consequently, it is only to be expected that the lay-out is in a number of factories far from perfect. The route followed from the intake of raw materials through the factory to the warehouse from which finished goods are finally despatched can thus leave much to be desired. From the time the blanks are made, they are handled very many times. Some handling is necessary, but investigations are proceeding to find ways to eliminate it wherever possible. Greater attention should be paid to the use of trucks or conveyors for the transportation of goods within the factory. Conveyors have distinct advantages, but they are fixed, and unless of the overhead type provide an obstruction at ground level; if they cannot be fairly fully used, the expenditure involved may not be justified. Trucks, jack-trucks and stillages may, however, be found to be more suitable, since they provide greater flexibility and can be readily transferred to a different route. Much then will depend on circumstances, but it is clear that one of the most important ways to reduce the losses due to breaking and chipping is to introduce the most efficient method of mechanical transportation from one point to another. It should not, however, be forgotten that any improvement in lay-out enabling transportation to be reduced or avoided would be still more desirable.

LOSSES THROUGH BREAKAGE AND OTHER CAUSES. In this industry internal losses, largely through breakage, form an appreciable item of cost. Hence a careful record should be kept of goods as they pass from one process to another. The introduction of such a system provides the supervisor with accurate daily returns, placing him in a position to trace major troubles promptly and to take steps to eliminate them. It is unnecessary to point out that as more and more work is expended on the ware, it becomes progressively more valuable. All factories appear to maintain such a system of recording, though in some it is more elaborate than in others. All will agree, however, that for maximum productivity the saleable ware in the packing case must account for as high a proportion as possible of the glass melted.

Hand-blown Domestic Glassware 42 1947

PACKING. Cases, barrels or crates are generally used as containers with straw or wood wool as the packing material. The goods are wrapped in tissue paper before packing. Wood wool is preferable to straw, but supplies are at present short and are available only for export goods.

We have given careful consideration to the question of carton packing. Contact was established with the pottery industry, and it was learnt that both experiment and experience show that the damage in transit in cartons is unexpectedly small. As a result the railway companies are now prepared to carry pottery packed in cartons at Company’s Risk. Carton manufacturers who have been approached have stated it would be possible to design standard cartons which could be adapted to accommodate a wide range of glassware by the use of suitable inserts.

Our American mission has reported that carton packing is used extensively, and indeed exclusively, for the cheaper types of glassware in the United States. As was seen there, carton packing can be made highly attractive and forms an excellent advertising medium. Some American buyers and importers thought that this type of packing was not suitable for the more expensive types of goods such as lead crystal glassware because the customer usually wishes to examine each piece carefully before buying. Others thought that it makes it easier for the consumer to buy if the goods are offered pre-packed and the glass manu­facturer can buy and pack cartons cheaper than the retail store. The big stores prefer to send the goods out in cartons branded with their own names.

Whilst at the moment a final opinion cannot be offered regarding the extent to which carton packing can be applied, it is clear to us that, since it promises considerable economies in labour and other costs and advantages in warehousing and in prompt despatch of orders, it should be subjected to close investigation by the industry.


Whilst each firm has its own costing system, we are convinced that there is a real need for a uniform system for the whole industry. It will admittedly not be easy to apply such a system to a trade where each article is hand-made, where wages are paid on a complicated “fractions” basis, and where an article may be sold plain or lightly or heavily cut or engraved, as a single piece of great value, or as a special matching, or again as one of many articles made to a standard pattern and sold in large quantities, but it has been done for similar industries. Not until such a system is in general operation will there be a reliable yardstick by which to measure efficiency or a basis for understanding between the individual manufacturers. We recommend that a uniform costing system be adopted without delay.


The decorators, who work under normal temperature conditions, are employed on a 48-hour week as before the war. In the glasshouse, where the men work under higher temperature conditions, the number of hours worked per week varies from factory to factory, but on the whole is less than the pre-war working week of 48 hours.

Eight of the factories operate a two-shift system, the hours nominally being 6 a.m. to 2 p.m., and 2 p.m. to 10 p.m. One factory has, until recently, been working a third shift, but at the instance {Glass-Study spelling: ?? insistence ??} of the workers it has been discontinued.

Hand-blown Domestic Glassware 43 1947

One factory works the morning shift only, whilst another has a day shift, 8 a.m. to 5.30 p.m., five days a week, and a night shift, 5.30 p.m. to 5.30 a.m., four nights a week.

Technical opinion is unable to agree on the best way to operate the glass­house, whether on a shift system, when three shifts daily would be preferred, or by night melting and day working. The principal factors involved are the size of the furnace and pots, the speed of filling and melting, the speed at which the glass is worked out of the pots (which depends on the kinds of articles being made), the number, skill and speed of the workers and the statutory limitations on the hours of working of youths. Our trade union members have emphasised that the Unions have never objected to the three-shift system, but there is undoubtedly strong feeling against it amongst the glass-makers themselves. It seems, moreover, to be going out of favour abroad. In Swedish and in most of the American hand factories a day shift only is now worked. Before this practice could be adopted generally here, modification of the glasshouses and of the processes would be necessary, otherwise costs of production would increase and output would fall. The situation may, however, be substantially changed as a result of the investigations now being made into the possibility of melting lead glass in tanks. If it should be found possible, with further advances in tank design and operation, to utilise continuous tanks for lead glass, the question of round-the-clock working would again arise; continuous melting demands continuous working of the glass.

The output per man year in our glasshouses is lower than in those of Continental Europe and the United States. The average number of hours in the nominal working week is lower than in any other country except the United States. Furthermore, the actual hours worked, particularly in the second shift, often fall short of the agreed number for the shift. The glassmakers themselves would be the first to agree that the average level of craftsmanship here is no higher than in certain European countries, notably Sweden, Czechoslovakia and Germany. The wages paid in our factories are higher than in any other country, the United States excepted. When normal competitive conditions return it is clear that the industry will have to face a difficult time, and all the efforts of our manufacturers, engineers and technologists to perfect the quality of the glass and secure greater economy in melting, fabrication and processing, will clearly be needed if the stable prosperity that we aim at is ever to be achieved.

In the hand-blown glass industry where the labour costs form such a high proportion (about 50 per cent.) of the total production costs, productivity per man year is of particular importance. Improvements in furnaces, lehrs and other plant and equipment will not of themselves ensure that production will be increased to the maximum extent. It will depend also, and indeed mainly, on the active co-operation of the workers themselves, and we recommend that management and labour in all sections of the industry should consult together to this end.


  1. That the industry should support the efforts being made at Loch Aline to provide a supply of high quality sand at a reasonable price.
  2. That the need for the industry to be assured of adequate supplies of red lead should receive close consideration by the Government Departments concerned.
Hand-blown Domestic Glassware 44 1947
  1. That the Raw Materials Department of the Board of Trade should take steps to ensure that present and future supplies of potassium carbonate are maintained at a level sufficient to meet the industry’s requirements.
  2. That the industry should continue and extend the investigations now being made into furnace design so as to determine the type of furnace which is efficient from the points of view of both glass melting and production of ware.
  3. That a careful study should be undertaken by the industry of the com­position and functioning of the glassmaking chair in order to secure a greater production efficiency in the glasshouse, due regard being had to the practice in other countries.
  4. That consideration should be given to the adoption of the pressed stem method of making stem ware and to the possibility of combining this with semi-automatic blowing of the bowls of the glasses.
  5. That the range and production of the industry should be expanded by the introduction of hand pressing of lead crystal ware and the manipula­tion of the pressed ware into other articles.
  6. That the possibilities of machines for making stem ware and other table­ware in half and full crystal should be thoroughly investigated with a view to their adoption by the industry.
  7. That the machinery which will be required should, wherever possible, be designed, developed and manufactured in the United Kingdom.
  8. That attention should be given in good time to the question of introducing the fire polishing process for machine-made ware into the factories.
  9. That the investigations into the ventilation of glasshouses should be continued and the improvements suggested be adopted by the industry.
  10. That efforts should be continued to develop a machine for burning-off without producing a thickened edge.
  11. That greater use should be made of the enamelling process of decoration.
  12. That mechanisation of the acid polishing process should receive further attention.
  13. That consideration should be given to the adoption of modern facilities for the transportation and storage of blanks and other ware in the factories.
  14. That the advantages and limitations of carton packing should be thoroughly investigated by the industry.
  15. That the industry should adopt a uniform costing system.
  16. That further efforts should be made by the management to secure the co-operation of the workers in obtaining the maximum output of goods from the production facilities available.