Updated 24-VII-2022

Niles-Mahoning Glass Plant

The GE Niles-Mahoning Glass Plant in fact consisted of two separate glass plants adjacent to each other on the same site. Although they operated independently and produced different products, in their later years they were amalgamated, and in view of their proximity they are described together on this page.

The General Electric Niles-Mahoning Glass Plant (Niles is in the background, with Mahoning in front)
The glass furnaces are located directly under the iconic horn-shaped Robertson air extractors along the rooftops

Address GE Niles/Mahoning Glass Plant #7646, 403 North Main Street, Niles, Ohio, U.S.A.
Location 41.1854°N, -80.7628°E.
Opened 1910 (Niles) & 1939 (Mahoning).
Closed 2008 (Niles) & 2010 (Mahoning).
Floorspace Unknown.
Products Niles: soda-lime glass bulbs & tubing, later #772 hardglass ribbon bulbs. Mahoning: borosilicate glass bulbs & #776 borosilicate pressings.

Foundation of the Niles Glass Plant
The oldest part of the building that eventually became the Niles Glass Plant was constructed during 1910 by the Fostoria Glass Company of Fostoria (Ohio), on the corner of Main Street and Federal Street. Its location was alongside the Mosquito Creek, which provided a ready source of water.

The precise origins of this company are not known, and are complicated because of the very large number of glass manufacturers operating in the town of Fostoria, Ohio. They were attracted to this town because of its location on the former Northwest Ohio's gas fields which offered a low cost source of gas for operating the glass furnaces. One of the principal businesses was the Fostoria Glass Company which had been founded in July 1887, but in the winter of 1890-91 it faced gas shortages due to the quick drying-up of the natural supply. By the end of December 1891 that company had relocated to Moundsville (West Virginia) in search of an uninterrupted supply of fuel. Its main products were decorative tableware. Although other references cite that the Niles Glassworks was built by the Fostoria Glass Company, it seems unlikely that it may have been this most famous brand.

Meanwhile, Fostoria remained home to several other glass manufacturers, three of which specialised in the manufacture of glass components for the electric lamp industry. These were principally set up to supply a lamp manufacturer in that same town, known as the Fostoria Lamp Company, a division of the National Electric Lamp Works, which was itself controlled by General Electric U.S.A. Its glass plants were the The Fostoria Glass Specialty Company which had been opened in 1899 by the lamp company itself, The Fostoria Bulb & Bottle Company which was acquired in 1899, and The Loudon Glass Works which was also acquired in 1902.

Fostoria was a small town with limited gas reserves, and as these began to dry up many of its glass producers relocated. That is possibly one of the reasons for the establishment of lamp glass production at Niles. But in any case, an extra factory was certainly required just in order to handle the vast production volumes and the Fostoria lamp glass production continued long after the opening of Niles. Prior to the construction of Niles, in addition to its own capacity from Fostoria GE bought the entire balance of the available bulb volume from Corning Glass of New York, and even had to resort to importing hand-blown bulbs from craftsmen in Austria and Germany.

From the outset, the Fostoria Glass Works at Niles produced hand blown glass bulb shells for incandescent lamps. Meanwhile the Fostoria facilities appear to have refocussed their effort on producing glass tubing and rod.

The Niles factory was built around two enormous circular kilns, rising from the floor and disappearing through the steel rafters of the roof and to the outside. Each furnace contained 16 ceramic pots around its base, these being filled with molten glass accessible via an arch-shaped opening and a vertical sliding door. Each of the 16 pots employed three men which were together known as a 'shop'. These comprised the 'gatherer', who would pick up a gob of molten glass onto the end of a five-foot iron tube, the blowing iron. This would be passed to the 'blower', who would roll it on a steel plate to make it cylindrical, swing it upwards and blow a small bubble, then swing it back and forth to achieve a uniform glass distribution before swiftly kicking a lever at his feet to bring a split mould upwards out of a water bath. The still soft glass pre-form would then be mounted at the mouth of the mould which closed around it, and inflated to its final shape by blowing while rotating the iron tube. The perfectly shaped bulb emerging from the mould, still attached to its iron tube, would next be passed to the 'carry boy' who would transport it to the position for breaking off the glass bulb. With small tap of a damp file on the bulb neck it would be severed from the iron and proceed to the 'glory hole' for annealing, while the boy would pass the iron tube back to the 'gatherer' to receive a fresh charge of glass.

By 1916 the Niles Glass Plant had grown to one hundred and forty of these 'shops' - with seventy running during the day, and the other seventy running during the night shift. The furnaces could not operated continuously because they were based on a batch process, a fresh charge of glass having to be made up in each of the pots every day followed by many hours of heating for the glass forming process to be completed. Each of these shops achieved an output of 534 bulbs per day - so the Niles site as a whole produced a daily output of only about 75,000 bulbs. A modern lamp glass factory achieves that output in three quarters of an hour from a single machine!

Mechanised Bulb Blowing
As described above, the production of glass bulbs was an immensely labour-intensive process. The capacity was limited and the high degree of manual labour made electric lamps rather expensive articles. Efforts to mechanise the process date back to Corning's 1912 invention of the Empire machine, the world's first semi-automatic bulb maker. One skilled plus two unskilled men could employ this machine to produce about 400 bulbs per hour, vs the 150 per hour produced by two skilled and one unskilled operator by hand. However, the first notable breakthrough came in 1916 when the Libbey Glass Manufacturing Company of Toledo, Ohio, succeeded in producing the first fully automatic bulb-blowing device. It was named the Westlake Machine, and even today more than a century later, these cast iron giants are still operating all around the world for the production of hollow glass objects.

GE purchased the rights to the Westlake machines, and in 1919 established yet another glass plant, the Pitney Glass Works at Cleveland (Ohio). From the outset it operated four Westlakes 24 hours per day from a single continuous glass furnace, and during its first year achieved a daily output of 65,000 bulbs per machine. By 1932 that capacity had been increased to 180,000 per machine per day. Naturally this spectacular new process usurped the manual process, and Niles Glass was quickly upgraded to employ the Westlake machines for all but a few special bub shapes, which continued to be blown by hand on account of their low volume requirements that could not justify the investment in automatic production. From this time onwards however, Niles ceased blowing bulbs for the high volume standard general service lamps and shifted its emphasis to handling the wide range of special and larger size bulbs.

In 1932 GE opened the New Pitney Glass Works at Euclid (Ohio) to house a still faster device, the Ribbon Machine, that had been invented by Corning in 1927. At its outset the Ribbon machines were capable of exceeding the Westlake speed and attained some 7000 bulbs per hour. The speed has since been driven up to in excess of 2000 bulbs per minute, or 120,000 per hour and well in excess of two million bulbs per day. One might think that this vast capacity would have fulfilled GE's requirements for glass bulb shells - but such is the volume of lamps required, that in 1937 additional Ribbon machines were built by GE to equip the Niles Glass Works.

Glass Tubing
At the outset, Niles had been conceived and built as a production facility only for glass bulbs. This changed during the Great Depression of the 1930s. Until that time the majority of the company's requirements for tubing had been turned out by GE's Bridgeville Glass Plant which superseded the old Fostoria operations, however the total volume required had never been very great and the depression put additional strains on maintaining that facility. In 1935 Bridgeville was closed, and the automatic drawing of glass tubing on Danner machines moved to Niles.

As such Niles produced a very important product, having delivered glass tubing for the original fluorescent tubes during their development by GE. Following the 1938/39 World's fair at which the fluorescent lamp was launched, demand skyrocketed and before long Niles was struggling to keep up. Bridgeville was hastily re-opened, followed by further glass tubing plants at Jackson (MS) in 1940, Bucyrus (OH) in 1941 and Logan (OH) in 1948.

Borosilicate Glass Pressings and the Mahoning Glass Plant
Until 1937 GE had paid little attention to borosilicate or 'hard' glass. It had been required only in tiny volumes for certain highly-loaded projection and discharge lamps. That changed following the company's invention of sealed beam automotive headlight lamps, which were produced from separate pressed-glass reflector and lens assemblies, fused together around their rims. Sealed beam lamps cannot be produced in ordinary soft glass owing to its inadequate mechanical strength - a low expansion coefficient glass having greater thermal shock resistance is essential.

At the time the principal source of such glasses in the USA was from the Corning Glass Works of New York, which employed it for pressing 'Pyrex' oven dishes and other domestic glassware. The optical quality of glass produced by that technique left a lot to be desired, and although it was suitable to prove the concept of the sealed beam lamp, it was clear that much greater quality standards would be required to bring the lamp into production.

An entirely new technique of glass pressing was developed by GE together with engineers from Corning and other glass producers, and in 1939 the Mahoning Glass Works was built alongside the Niles facility to specialise solely in the production of pressed borosilicate ware for automotive sealed beam lamps. The onset of World War II and the resulting government ban on construction of new cars curtailed that business for the new lamps, but they found countless other applications in specialty lamp types essential to the war effort. They were copied around the world, and for the duration of WWII the Mahoning Glass Plant was the world's sole source of pressed glassware for sealed beam lamps. The end of the war unleased a sudden pent-up demand from the automobile industry, and the preparatory work carried out by Mahoning in perfecting the necessary glass components led to an enormous boom which outstripped its own capabilities. The extra demand was met by opening the Kentucky Glass Plant in 1946, whice relocated to the Somerset Glass Plant in 1959. The Mahoning glass plant did not close and continued its pressed borosilicate operation until 2010, when following declining volumes, its 109 workers were made redundant and its production was transferred to Somerset.

Borosilicate Glass Bulbs at Niles
In the latter half of the 1900s, the requirement for borosilicate glass bulbs began to grow due to the rising popularity of high intensity discharge lamps, whose high operating temperatures called for the use of more thermally stable glass types. It is not certain when or where GE commenced production of hard glass bulbs, but as the company's first hard glass production facility it is perhaps logical that these were produced at Mahoning.

Borosilicate bulbs are required in much lower volumes than the ordinary soda-lime bulb shells of incandescent lamps, and until the 1980s were produced by most lamp manufacturers using the older slow-speed Westlake or carousel type of equipment. The adjacent Niles Glass Plant undertook an ambitious project to attempt to produce hard glass bulbs on one of its Ribbon Machines. This was facilitated somewhat by the fact that the American lampmakers then employed leaded borosilicate glass rather than its lead-free counterpart employed by much of the rest of the world. The high lead content makes the glass easier to work and lowers the softening temperature. This led to GE's impressive success in the 1980s to establish the world's first and only ribbon machine for the production of borosilicate glass bulbs. Their dimensional consistency and low cost made them especially popular, and GE Niles-Mahoning branded cardboard packaging boxes used to be a familiar sight not only within the GE lamp plants but also at its principal competitors all around the globe.

Decline and Closure
Following the gradual replacement of many traditional lamps by more advanced light sources in the early 2000s, along with GE's relocation of the bulk of its lamp manufacturing from the USA to cheaper countries such as Hungary and Mexico, the customers of the Niles-Mahoning glass plants began to decline and move further afield. This had a severe impact on production volumes, especially because Niles was producing mainly the larger and specialty glass bulbs for high wattage incandescent lamps which were among the first to be replaced by more efficient types. In October 2007 it was decided to terminate the manufacture of soft glass - the bulb volume being absorbed by the Kentucky Glass Plant while tubing demand was taken over by the Logan Glass Plant and Bridgeville Glass Plant. Niles was operating at 50% below capacity and in recent years had been shut down for 13 weeks each year due to overcapacity. This finally led to its closure in 2008 with the loss of 57 jobs.

A few years after this a similar impact was felt on the hardglass operations. The production of pressed borosilicate lenses and reflectors was absorbed by the newer Somerset Glass Plant, and following GE's termination of HID lamp production within the USA those bulbs were only required at its Hungarian Tungsram operations. Hungary had its own local hard glass bulb production at the Nagykanizsa Glass Plant, and although that was based on older slow-speed processes, another important change at the time was a global shift away from lead-containing glasses. Despite the beautiful high-speed production of borosilicate glass bulbs on the Niles-Mahoning ribbon machine, it would not have been realistic to convert that process to use lead-free glass. This sad situation led to the closure of the Mahoning facility on 5th April 2010, three months earlier than originally planned, with the loss of 109 jobs.

In 2013 GE made a significant investment of $ 274,000 to remove asbestos from much of the site which was demolished in 2015, while the newer part of the building was prepared for sale.

Niles Glass Plant, 1930s Niles Glass Shop, c.1915 1 Niles-Mahoning Glass Plant

Glass Products
1980 - US
Glass Products
1990 - US
Soda-lime Silicate Bulbs
1981 - US
Borosilicate Pressings
1979 - US

References & Bibliography
  1. A Century of Light, James A. Cox, published by The Benjamin Company / Rutgers, 1979, ISBN 0-87502-062-3, pp.134, 135, 137, 140, 141.
  2. Fostoria Glass Works and General Electric Plant, The Niles Historical Society Website.
  3. Auto Headlight Glass : Visible Features of Forensic Utility, US National Bureau of Standards Report, February 1978.
  4. GE to Close Niles, Austintown Plants, The Business Journal, 16 Oct 2007.
  5. General Electric to Close Plants, cut 130 Jobs, The Budapest Business Journal, 05 Oct 2007.
  6. Niles Mahoning Glass Plant is Closing, The Niles Register, Nov-Dec 2009, p.4.
  7. Niles GE Plant Closing Three Months Early, WFMJ News, 27 Jan 2010.
  8. GE Set to Tear Down Plants, Tribune Chronicle, 21 Jun 2013.
  9. Private Communication with Jim Maderitz, former employee of 43 years, October 2021.