Volume 9, Issue 4 - August/September 2007

Off the Line
oem glass manufacturing

Fare Thee Well
by Russ Corsi

Author’s Note: The historical information shared in this article should be credited to two PPG Industries marketing brochures entitled “Romance of Glass,” which were published circa 1962-1973. 

As a PPG Industries retiree that spent my entire 31-year-plus career in the glass group, the current attempt to sell the OEM and ARG businesses touches a sentimental cord (see related story in the March/April/May 2007 issue of AGRR, page 20). I hope that you won’t mind my dedicating this article to share a little bit of history with you.

A Look Back
Captain John B. Ford and John Pitcairn founded the first commercially successful plate glass manufacturing plant that was built in North America in Creighton, Pa., in 1883. 

Although originally organized as the New York City Plate Glass Co. in 1880, the company was re-organized as Pittsburgh Plate Glass Co. (PPG) in 1883.The plate glass manufacturing process remained virtually unchanged from 1688 until about 1920. Generally speaking, this process included the following operations: mixing, melting, rolling, annealing, grinding, polishing and cutting. Because the annealing step was the most time-consuming, Pittsburgh Plate Glass Co. formed its first research and development group in 1910 to focus on reducing the amount of time required to anneal glass. 

The group’s diligent efforts helped them succeed in inventing the lehr. A lehr essentially is a very long oven with a continuous conveyor that allows glass to enter at about 1500 degrees Fahrenheit and to cool gradually as it travels through the remaining footage of the lehr. Going from a kiln (box oven) to a lehr reduced the annealing time from ten days to a few hours.

The Wonder Years
PPG’s research group continued working on the other manufacturing steps from 1925 to 1935 to address the remaining manufacturing steps. The fruit of the company’s efforts was a smooth-operating, continuous process. Several hundred patents were awarded to the PPG employees that were involved in this gallant effort.

Although many improvements were applied constantly to the plate glass process, the float glass technology developed by Pilkington became the state-of-the-art process because of its lower manufacturing costs while maintaining acceptable product quality.

PPG licensed the float process from Pilkington and built a float line at its Cumberland, Md., plant in 1964 and ran it in parallel with a plate line that was eventually shut down. From this point forward, all new conventional flat glass lines that PPG built employed the float process. PPG maintained a dynamic research and development and engineering program, commencing in the early 20th century. The research group was charged with continuously extending the technology while the engineering group was challenged to create new and improved products.

The ever-growing demands of both the architectural and transportation communities necessitated the designing and producing of a continuous line of value-added products.

The architectural arena saw the introduction of insulating, tempered, heat-strengthened, and laminated products that utilized glass that reflected or absorbed heat loads, as required. 

Automotive Increase
The transportation world quickly evolved from monolithic pieces of sheet and plate glass to laminated, tempered, heat-strengthened, solar-reflecting or absorbing substrates that found applications ranging from the aircraft industry to the rail industry to the automotive industry.

A significant number of the products that were introduced were designed internally at PPG and fabricated on manufacturing equipment that was specified by PPG engineers.

PPG re-focused the glass group’s geographic presence to North America after both the European and Asian glass operations were divested in the 1990s. 

I sincerely hope that other PPG retirees that also had the opportunity to spend a significant amount of their employment years in the glass businesses that are affected by the current divesture activities will join me in the hope that when all the dust settles, the rich tradition that was started by the early Pittsburgh Plate Glass pioneers will remain intact. 

Russ Corsi retired as manager of technical services from PPG Industries’ Automotive Replacement Glass business unit after 31 years in the glass industry. He now serves as a consultant to the industry. Mr. Corsi’s opinions are solely his own and not necessarily those of this magazine.

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