German Glass Industry Report 27 on

German Glass Industry 122 After September 1945


  Target No.
Map Ref.
Name of Target Glaswerke Ruhr A.G.
Address Essen-Karnap
Date of Visit 9th August, 1945
Products Bottles, and wide mouth jars, e.g. home preserving jars, sweet jars.
Pressed and blown ware.
Tubing, including pill tubing and ampoule tubing.
Present Position The plant is operating 1 tank furnace out of 5. Two have been destroyed by bombing, the fourth is idle and the fifth is being rebuilt and would probably be ready in September. None of the 5 furnaces feeding the Danner tube drawing machines is in operation, though all are undamaged. The market for the tubing was in Thuringia and no orders are now coming through. Very recently they had been informed that they would be able to make ampoule tubing of the Fiolax type (modified composition - see later) for the I.G. Farben-industrie. No complaint is made of shortage of raw materials and coke oven gas is available from the Hugo Stinnes coke oven plant nearby, which itself adjoins the colliery. (The firm is a subsidiary of the Stinnea organisation.)
Key Personnel Herr Erich Kukal (Commercial Director)
Dr. Hans Broche (Technical Director)
Dr. R. Allolio (Chief Engineer and Technologist.)
Plant 5 Tank furnaces (2 seriously damaged) for bottles, etc., and lehrs to match.
5 small Tank furnaces for tubing
2 Owens machines
At least 18 press and blow machines with feeders. Sundry hand presses
German Glass Industry 123 After September 1945
Plant 8 Danner tube drawing machines
Producer gas plant as auxiliary to coke oven gas.
Batch weighing and mixing plant
Employees Pre-war
1,500 - 1,600

Description of Plant, processes, etc.

1. General

The plant is a fairly large one for making bottles, jars and tubing, and consists of 5 tanks for bottles and 5 tanks for tubing production. It is situated very near to a coal mine and coke oven plant and so can be operated on coke oven gas, although this is mixed sometimes with producer gas.

2. Bottle Making Plant

There was nothing novel about the plant. The glass was melted at 1,470 in large cross-flame regeneratively-fired tanks, 5.5 metres in breadth by 11 metres in length. The floor of the working end was raised so that the depth of glass was 1 m. in the melting end and 0.75 m. in the working end. The throat connecting the two compartments measured 600 x 250 mm. The working end was of the usual semi-circular construction to accommodate either 6 bottle making machines or 4 machines and 2 positions for hand-gathering for pressed ware. The melting end of the furnace was heated by 4 burners either side. As shown in Drawing 7 the working end was recuperatively fired using two burners and exhausting through the double crown. The melting area was 50 sq. m. and the daily production 70 tons. The doghouse was covered, batch feeding being through a hole in the cover. The clay tank blocks contained 25 per cent. alumina and were similar to Didier in quality but were made by the firm Dr. Karl Otto of Dolhausen. Full depth blocks were used. Each tank needed 75,000-80,000 cu. m. of gas per day of 4,300 cal. per cu. m. calorific value.

“E” type Miller press and blow machines with Hartford feeders were making preserving jars from the one tank in operation, but another tank was equipped with a 6-arm Owens machine operating from a fixed forehearth. The life of the tanks was 14-l6 months on colourless bottle glass of the composition given in Table V.

Batch mixing was fully automatic; the different materials were fed from hoppers on to a conveyor belt by rocking feed arms placed in the discharges of the hoppers. The amount of oscillation could be varied by rachet mechanism. It was stated to be accurate

German Glass Industry 124 After September 1945

to 1œ per cent. The batch was then mixed in a double-bladed revolving mixing machine and conveyed to the feed hoppers by an automatic electric overhead tramway. Some 3œ-4% of water was added by means of 6 pipes entering the top of the mixer casing in order to cut down (a) segregation (b) dust carry-over in the furnace. The batch preparation, though highly mechanised, was by no means clean or impressive.

3. Tube Plant

Five tanks of respectively 8, 11, 17, 17 and 17 sq. m. melting area of the general plan shown in Drawing 6 (Wanne D) were used to melt soda-lime glass in AR, LR and LR amber, the compositions of which are given in Table V. A tank of melting area 4.5 sq. m. was found to be too small. The tanks are of the horseshoe flame type fired on the regenerative system. The largest tanks were 5.25 m. long x 3.6 m. broad at the filling end, the depth of glass being 0.9 m* The main dimensions are given below. The production of glass was 14 tons per day from the largest tanks and averaged 11 to 12 tons. Life was 16-18 months. The production of tubing was 125 tons per month from each machine. Drawing was done horizontally by Danner machine but since the plant was not in operation through lack of orders, no estimate could be made of quality and speed of draw. Clay blocks of the same quality as those used for the large tanks were used. Lead glass had never been made in this plant. They propose making chemically neutral glass to a modification of the Jena “Fiolax” formula to be used by I.G. Farbenindustrie for ampoules.

4. Dimensions of Danner Tube Drawing Tank Furnace (Wanne “D”)

The following information has been taken from the record sheet for the run lasting from 10th June, 1938 to 3rd November, 1939

Melting end  
Glass Depth 900 mm.
Surface area 17.00 sq. m.
Glass Volume 15.30 cu. m.
Glass weight 38.25 tons
Length 5,250 mm.
Width 3,600 - 3,300 mm.
Working end  
Glass Depth 900 mm.
Surface area 5.40 sq. m.
Glass Volume 4.85 cu. m.
Glass weight 12.10 tons
German Glass Industry 125 After September 1945
Width 600 mm.
Height 300 mm.
Cross Section 0.17 sq. m.
Length 1,300 mm.
Glass Weight 0.550 tons
Distance from top of throat to glass level 600 mm.
Length 1,400 mm.
Width 500 mm.
Glass Weight 1.55 tons
Glass Weight in channels 2.50 tons
Total glass weight 54.98 tons
Width 520 mm.
Height 400 mm.
Cross Section 0.19 sq. m.
Height 2,100 - 2,900 mm.
Width 1,430 mm.
Length 2,350 - 2,800 mm.
Total volume 6.6 - 11.0 cu. m.
Packing volume 4.8 - 8.6 cu. m.
Free checker surface 214 sq. m.
Weight of checker work 10.2 tons
Recuperator heating surface 24 sq. m.
Working end Port  
Width 250 mm.
Height 200 mm.
Cross section 0.048 sq. m.

5. Glass Compositions

These are given in Table V. A tubing glass (known as “Later AR”) was developed during the war owing to a scarcity of boric oxide; it was considered to be an improvement on the original “AR” glass and will be retained. No arsenic or antimony was used in the glass tubing batches.

The “LR Amber” batch is similar to the “LR Colourless” batch except that 2 Kg. coal, 7.2 Kg. sodium sulphate and 0.4 Kg. ferric sulphide are added to 240 Kg. of the colourless batch.

German Glass Industry 126 After September 1945

Table V

Compositions of Glasses made at Glaswerke Ruhr A.G.

Colourless Container Glass Tubing Glasses LR Colourless Jena Fiolax

AR Later AR
SiO2 74.8   71.0   70.0   68.5   64.5  
Na2O 15.0   11.4   10.8   16.6   5.4  
K2O 0.5   5.0   5.0   2.9   1.4  
Al2O3 1.3   3.8   5.0   4.0   6.6  
CaO 7.6   7.0   7.5   7.0   7.8  
MgO 0.2   0.2   0.2   0.2      
B2O3   1.5       0.8  
ZnO     1.5     6.3  
BaO         7.0  

TOTAL 99.4   99.9   100.0   99.2   99.8  
German Glass Industry 127 After September 1945


  Target No.
Map Ref.
Name of Target Osswald und Co.
Address Not known. Said to be Hamburg.
Date of Enquiry 5th and 6th August, 1945
Present Position  
Key Personnel  
Furnaces, Plant, etc.  
Employees Pre-war


This target was placed on the Target List by T.I.I.C. as a concern producing (or associated in some way with activities in) glass wool for insulation purposes.

Enquiry at the Oscar Gossler factory at Bergedorf having proved fruitless, a search of the Hamburg telephone directory produced an address which was investigated but no Osswald was known. All that could be gathered was that the firm was either one of patent lawyers or that Osswald was an inventor who had tackled fibre glass production.

German Glass Industry 128 After September 1945


  Target No.
Map Ref.
Name of Target Rohm und Haas
Address Darmstadt
Date of Visit 19th September, 1945
Products Plastics used in making laminated glass, etc
Present Position See report of Chemicals Committee on Section Target 22/42 (a), G.2. SHAEF (Rear) by Kearn Murray and Sudhoff of C.W.S., H.Q., ETOUSA, located at Frankfurt T.I.I.C., H.Q., Höchst in charge of Mr. B. H. Wilcox, A.P.O. 757.

It was ascertained that none of the plastics made either at this plant or at a Berlin one run by the firm proved suitable as substitutes for optical glass. The methyl methacrylate monomer (“Plexiglas”) producing unit was said to be capable of being worked if the buildings were repaired.

Key Personnel

Management Board:
Key Personnel Dr. Stauss (Chemist)
Dr. Müller (Chemist)
Dr. Kaulter (Chem. Engineer)

Dr. Tromsdorf

Dr. Röhm

German Glass Industry 129 After September 1945


  Target No.
Map Ref.
Name of Target Vereinigte Farbenglaswerke A.G.
Address Zwiesel
Date of Visit 7th September, 1945
Products Optical glass including large cast blocks.
Present Position The plant, an old lead crystal glass factory had been taken over by the Schott organisation and completely remodelled for the production of optical glass on the same lines as at Jena. The scheme was 90% completed when the Allied Advance stopped work. The plant was at the tine of the visit occupied by displaced Poles.
Key Personnel Herr F. W. Jegner (Director)

Description of Process

The following is a brief description of the method of preparing blocks of optical glass approximately 48 x 48 x 14 inches by casting in iron moulds. The batch was mixed in a rotary drum at one end of an L-shaped building. It was then moved in a car (or by an overhead crane) to the pot furnaces. Here it was charged into the pots according to standard practice. The furnace room included ample pot heating furnaces and six single pot melting furnaces were nearly ready to light up. All of these furnaces showed careful design and construction although they were somewhat different from those sometimes used. Both air and gas pressure were carefully controlled. Each furnace had its own air and gas regenerative chambers on both sides of the furnace. The combustion ports which were about 6 in. by 8 in. in size, were cleverly placed somewhat above the furnace floor and directed upwards along a “bee-hive” curved side-wall and cap which started at the floor on one side and arched clean over to the ports and floor on the other side. This cap which was of silica brick about 6 inches thick, was insulated with about 12 inches of natural silica insulating brick. All of these cap blocks were fitted carefully and then sealed with a thin coating of high temperature cement before application of the insulation. The front and back walls were straight with the curved arch between them. Pot stools rose about 8 inches above the floor.

German Glass Industry 130 After September 1945

A 6 inch slag hole was located at the centre at the rear and all the floor sloped toward this. The door was in one piece covering the whole end of the furnace and it had a stirring and observation hole about 6 inches high and 18 inches wide, located just above the pot brim level. It was about 12 inches thick and was removed by a heavy screw winch device. It was of ordinary good quality coarse grog and fireclay construction and had a projection which fitted into the end of the furnace when the door was closed. The stirring machines appeared to be of very substantial design but very similar to older standard types. The pots were about 38 inches deep and 48 inches in diameter. They were purchased outside and were used several times. After melting and mixing the glass was cast into five-piece heavy iron moulds. These consisted of a heavy iron bottom about 1œ inches thick and about 48 inches square. On the edges of this plate were four comer plates about 1œ inches thick and 14 inches high. When all four of these were clamped to the bottom plate an open box was formed. Before casting the inside of the mould was coated with a refractory powder. The glass was cast into this mould which was supported on a car; this was then moved to the cooling room. The latter was a separate and well organized department complete with adequate electrical control and well insulated cooling chambers. Two of the cast blocks of glass were placed at a distance of about 12 inches one above the other on a substantial base made of stools between which electrical heaters were placed. Corrugated iron hoods having about 12 inches of powder type thermal insulation were then lowered over the hot glass and the very carefully controlled cooling schedule depending on the glass composition was started. The treatment might last for over two months.

After cooling, the large blocks of glass were placed across heavy parallel supports and sufficient load applied at the centre to break them. The pieces were then taken to other departments where they were further reduced, examined, sorted, cut, sawed, pressed, polished and put through the usual processing.

German Glass Industry 131 After September 1945


  Target No.
Map Ref.
Name of Target Fredener Glasmanufaktur C. Runge u. Sohn.
Address Klein-Freden, Prov. Hannover
Date of Visit 4th August, 1945
Products Bent, bevelled and silvered glass
Present Position Undamaged. The firm is a small one and only employed 10 persons pre-war, sinking to 5 during the war. No bending had been done for 9 months owing to lack of fuel.
War Time Activities

(l) Fitting toughened “Thorax” sheet discs into parabolic reflectors.
(2) Edge-grinding cylinders for operating theatre lights

Furnaces, Plant, etc. 1 two-compartment bending kiln to take 100 cm. x 60 cm. sheets.
Simple edge-grinding and polishing plant.
Key Personnel Herr Runge, who was absent at time of visit.
German Glass Industry 132 After September 1945


  Target No.
Map Ref.
Name of Target Kreinse und Co
Address Gross-Freden a.d. Leine
Date of Visit 4th August, 1945
Products Bent, bevelled and silvered glass articles, e.g. photoframes, door plates, electric light switch plates.
Present Position Almost at a standstill owing to lack of glass which was previously obtained from Witten.
Key Personnel Herr Kreinse
Employees Pre-war
German Glass Industry 133 After September 1945


  Target No.
Map Ref.
(Not yet allocated)

List of Small Works in Furth (Nr. Numberg) engaged in Optical Glass Industry

When trying to trace S. Bendit und Sohne, reported to have produced optical glass, it was learned that there were numerous small firms in Fürth engaged in processing optical glass. A list is given below.

S. Bendit u. Söhne. Bought up by Deutsche Spiegelglas in 1936

Spiegel und Flachglas. Dr. Dietl, Waldstrasse 49. Do not produce glass, buying it from Bayerische Spiegelglas.

Fürther Spiegelglas, Gebhardstrasse 17

Frankische Metall und Spiegelfabrik, Höfenerstrasse 66.

Höfling, W. u. M., Tannenstrasse, 6.

Kraus Christ und Co., Theaterstrasse, 49

Anton Matscheko, Mathildenstrasse, 20

Scherber und Gotz, Adolf Hitler Strasse, 46 {Glass-Study: Renamed Hauptstrasse, established 1860.}

Georg Schmerler, Schillerstrasse, 5

Georg Trummeter, Pfisterstrasse, 14

Union Brillenfabrik, Hindenburgstrasse, 37

Georg Vogler, Schwabacherstrasse, 298

Phillip Winter, Schlageterplatz, 10

None of these small firms were visited.

German Glass Industry 134 After September 1945


  Target No.
Map Ref.
Name of Target Deutsche Gold und Silber Anstalt (Degussa)
Address Frankfürt a/Maine, Gutleut Strasse
Date of Visit 16th August, 1945
Products Cyanides, special Refractories (Alumina, Magnesia, Spinel, Beryllia, Thoria, Zircon, Zirconia) and Lightweight Concrete for building.
Present Position The only part of the plant seen working was that making lightweight concrete building blocks. Most of the remaining buildings had been severely damaged if not entirely destroyed. This section was stated to be capable of making 24,000 cu. m. of blocks per week though at the time of the visit it was producing only 3,000 cu. m. per week owing to shortage of moulds. The bulk density of the product can be varied between 400 and 840 Kg. per cu. m. and the size of pores can be controlled. These pores are closed so that the blocks are not permeable and the texture of the material was very uniform. The blocks are used in particular for partition walls in building.
Key Personnel seen “Meister” Reichert - the Head of this Department being away.
Furnaces, Plant, etc. This consisted of a small Eirich mixer with a bosh alongside holding the bleaching powder milk (1:1) previously agitated in a small mixer, together with simple sheet iron moulds and a drying shed.
Employees About 6 (including 3 or 4 women.)

Description of Process

A typical mix for light weight blocks is as follows:

Cement (Portland) 350 - 400 Kg.
Building Sand (0-3 mm.) 200 Kg.
Ground Sand (Quarzmeal) 50 Kg.

German Glass Industry 135 After September 1945

This is mixed with 120 litres water at about 28°C. for 2 min. then mixed with 4 - 4.5 litres “40 Vol.” hydrogen peroxide containing 15 - 50 cu. cm. saponin for a further 30 sec. Then bleaching powder cream (1:1) is added in amounts equal to 8 - 10 times that of the hydrogen peroxide used. Mixing is continued for a further 40 - 60 sec. causing the material to froth. It is then poured into sheet iron or wooden moulds through an opening in the bottom of the mixing pan. After setting for a suitable time, about two hours, it is sawn up into smaller sizes by a large bow saw, the mould sides being slotted to act as guides for the saw. One mould for example would produce about 20 blocks each measuring 30 x 25 x 14. cm. The sawn blocks are removed from the mould 24 hrs. after casting.

The compressive strength of the material was stated to vary from 6 - 25 Kg. per sq. cm. depending on its bulk density. Bulk density and pore size are controlled by the relative proportions of the foaming agents added. It would appear that this firm has succeeded in stabilising a lightweight concrete and that this is accomplished by strict control of additions and the temperature of the mix. Experiments had been proceeding since 1929 though this plant had only operated since 1940. Strict control is obviously needed as one mix was seen which was too dense owing to the use of insufficient water, which allowed the gas to escape.

Samples were taken to include (1) this lightweight concrete, (2) refractory oxide crucibles and (3) an alumina cutting tool.
German Glass Industry 136 After September 1945


  Target No.
Map Ref.
Name of Target Badische Verteilungestelle und Ziegelei.
Address Weltzienstrasse, 30, Karlsruhe
Date of Visit 22nd August, 1945
Products Roofing and decorative (“backstein”) tiles for building purposes. The concern is a central organisation, of which Dr. Link is the director, representing some 75 small firms in the U.S. and French zones.
Present Position Only one or two of the factories have been damaged in the war but only three or four factories are now working owing to lack of coal.
Key Personnel Dr. Link at the address above, which was his private residence.
Productive Capacity There are 21 factories in the Mannheim (N. Baden) district, 9 in the Karlsruhe (Mid. Baden) district and 43 in the French zone. Dr. Link gave the following information on the production of roofing tiles and “backstein” tiles:
  No. factories making Roofing Tiles Production of Roofing Tiles (Millions per year) No. factories making “Backstein” Production of “Backstein” (Millions per year)
Mannheim district 9 35 21 86
Karlsruhe district 1 7 9 31.5
French zone 9 17 43 120
Glass Interest Dr. Link said he had nothing to do with glass used in building.
New Developments Dr. Link stated that the only thing in this connection was the use of light weight concrcrete in the form of slabs for partition walls.
German Glass Industry 137 After September 1945


  Target No.
Map Ref.
Name of Target Technische Hochschule
Address Karlsruhe
Date of Visit 21st August, 1945
Comments The buildings had been much damaged but Professors Theodor Poschl and Rudolf Scholder were traced to their homes (5 Wendstrasse and 3 Kriemhildenstrasse respectively) in Karlsruhe with the object of finding out whether or not research on glass subjects had proceeded since the departure of Dr. A. Dietzel to the K.W.I, in Berlin before the war. These gentlemen confirmed that no successor to Dr. Dietzel was appointed and that no such work had since been carried out. They stated that the new Head of the Hochschule was Prof. Dr. Ing. Rudolph Planck of 15 Bismarckstrasse, Ettlingen.
German Glass Industry 138 After September 1945


  Target No.
Map Ref.
(See below)
Name of Target Kaiser Wilhelm-Institut für Silicatforschung
Addresses Berlin-Dahlem (L53/Z75)
Ostheim-Mellrichstadt (L51/H7O)
Fladungen (L51/H71)
Date of Visits 1st October, 1945 (Berlin)
11th September, l945 (Ostheim and Fladungen.)
Persons Seen Prof. Dr. W. Eitel (See Report XXXVIII)
Dr. A. Dietzel (At Ostheim.)
Present Position Prof. Eitel some three years ago dispersed the apparatus, library and personnel of the K.W.I. among the small towns of the Mellrichstadt neighbourhood. Much of the more valuable apparatus was housed in an old museum in Fladungen (e.g. electron microscope, X-ray equipment for crystal analysis, spectrograph, petrographic and other microscopes and a complete instrument making workshop.) At Ostheim the Institut Library was intact but not adequately protected in an old box factory into which much equipment was also packed. Other laboratories were housed at Bischofsheim (L51/H60) and Königshofen (M51/N99).

Activities during War Time

(1) Investigation of method of preparing synthetic mica.

(2) Search for substitute materials, particularly for boric oxide.

(3) Numerous other investigations as indicated by published work given below.

German Glass Industry 139 After September 1945

List of Publications Reporting Investigations Carried Out
by Prof. Dr. A. Dietzel and his Co-Workers of the K.W.I. für Silikatforschung during the period 1938 - l945

On the chemistry of the colouring process in glasses coloured by metal colloids. Zeitschr. Elektrochemie, 1945. 51, 32.

Separation of Heavy Metal Halogenides in Glasses
Naturwissenschaften 1944, p.217.

New rapid method of determining the alumina content in refractory clays or fire-bricks. Berichte d. Deutschen Keramischen Gesellschaft 1943, 24, 283.

Soda-slag as a raw material for the glass and enamel industry. Sprechsaal 1943, 76, No. 17

Researches on enamelled boiler-plates. Sprechsaal 1944, 77, 1

On the structure of silicate glasses. Naturwissenschaften 1943; 31, 110.

The utilisation of soda-slag. Glastechnische Berichte 1942, 20 321.

Explanation of anomalous expansion phenomena in silica and special glasses. Naturwissenschaften 1943, 31, 22.

On titanium dioxide and its effect in enamels, glazes and glasses. Part IV: The Turbidity of Enamels produced by Titanium Dioxide. Sprechsaal 1942, 75, Nr. 33

Relation between surface tension and structure of Glass melts. Kolloid-Zeitschr. 1942, 100, 368

Change in the technical properties of enamels by replacing boric acid. Sprechsaal 1942, 75, No. 17

Practical importance and calculation of the surface tension of Glasses, Glazes and Enamels. Sprechsaal 1942, 75, Nr. 9

Researches on the annealing and rapid cooling of glasses. Glastechnische Berichte 1942, 20, 1

Relation between expansion coefficient and structure of glasses. Glastechnische Berichte 1941, 19, 319

Cation strength and its relation to devitrification, formation of compounds and the melting point of silicates. Zeitschr. Elektrochemie 1942, 48, 9

German Glass Industry 140 After September 1945

The structural chemistry of glass. Naturwissenschaften 1941, 29, 537.

Points of view in crystal chemistry in explaining the constitution of glasses. Naturwissenschaften 1941, 29, 81.

On titanium dioxide and its effect in enamels.
Part III: Effect of Titanium Dioxide on the Chemical Durability of Enamels. Sprechsaal 1941, 74, No. 47
Part II: Experience on the Effect of Titanium Dioxide in Enamels and Glasses. Sprechsaal 1941, 74, No. 39
Part I: Introduction. Sprechsaal 1941, 74, No. 31

Effect of titanium dioxide on the colour of glasses and the theory of structure. Glastechnische Berichte 1941, 19, 217.

The systematics of the sulphide selenide and telluride colours in glasses. Glastechnische Berichte 1941, 19, 4.

The role of zinc oxide in glasses containing sulphur or selenium. Glastechnische Berichte 1941, 19, 1.

Evaporation of alkali from sodium-lime-glasses during heating (devitrification.) Glastechnische Berichte 1941, 19, 256.

Influence of magnesia on the devitrification constants of sodium lime glasses. Glastechnische Berichte 1941, 19, 43.

The colouring agents (bodies) in the so called carbon-yellow glasses (amber glasses.)
Part III: Colours produced by Iron-Sulphur-Compounds. Glastechnische Berichte 1940, 18, 267.
Part II: Colouring by Polysulphides. Glastechnische Berichte 1939, 17, 286.
Part I: Glastechnische Berichte 1938, 16, 389.

The significance of the basicity of glass melts and investigations with the object of measuring it. Glastechnische Berichte 1940, 18, 297.

Electrochemical measurements of the oxygen partial pressure in glass melts. Glastechnische Berichte 1940, 18, 33.

Molybdenum in enamels. Emailwarenindustrie 1941, 18, 30.