Reflections of a Glass Maker

By Alan Slavich

Reflections of a Glass Maker is a unique look into the history and transition of the flat glass industry in the United States as told by an insider. Flat glass is a vital part of our lives, as it provides protection from the elements and views of the world. The making of flat glass is an ancient process but has been a mystery to most of civilization since it was first invented. The evolution of flat glass processes is covered in this book. The latest evolution in flat glass production is a remarkable new invention called the float glass process that was invented in the 1950s by the Pilkington company in England. The amazing float glass process was introduced into the United States in 1963. This new process completely transformed the flat glass industry forever.

The invention of float glass allowed much higher production levels with increasingly higher quality of the finished product. The author began his career in the float glass industry in 1963 and retired after fifty-five years in the industry. He entered the industry at such a unique time and was able to watch as the very old flat glass processes were replaced by the new revolutionary float glass process. He relates experiences with three different companies that utilize the float glass process. He shares some technical data and history of the flat glass industry as well as some humorous instances that occurred along the way. The book gives the reader a comprehensive look at an industry about which most people simply know very little.

• Language: English
• Publisher: Page Publishing, Inc.
• Release date: Apr 28, 2021
• ISBN: 9781662429798

Book preview

College

I was always a good student and knew that I would go to college, but when I was young, I did not think much about what I would do when I got older. Since I was always an excellent student in math, I assumed I would be an engineer of some kind, probably a civil engineer, so I could work outdoors in the great northwest. I grew up in Tacoma, Washington and graduated from Stadium High School in 1958, so I also assumed I would find a job somewhere in Washington. I never started out to be a glassmaker.

Glassmaking was the farthest thing from my mind as a career when I went to college. I guess I thought like most people when it came to glass. Glass is just there. I only knew little about the history of this fascinating product or the methods used to make the windows that surround our everyday lives.

My grades through high school got me a scholarship from the Moose Lodge for $1,000 when I graduated from Stadium High School. In those years, the tuition to the University of Washington was less than $100 per quarter for in state students, so that money covered my tuition for the next four years.

What was I to do about housing at school? I picked berries and worked for a farmer during the summers in Puyallup to earn money to pay for school clothes and books, but I sure didn’t have money left for a car or an apartment. The dorms also would cost money that I didn’t have, and my folks didn’t want to take out a loan to pay for housing at the university.

Fortunately, one of the things that the fraternities at the University of Washington did was look for new students with a good grade point average and invite them to rush parties. The frats were always looking for good students to help the frat grade point so they could stay on the good side of the university administration. I went to several of these parties and eventually made a decision to pledge Sigma Phi Epsilon fraternity since they would allow me to be a houseboy and wash dishes for two meals a day, which would cover my room and board. I did this all the way through college so I never needed a lot of extra money, and my parents would occasionally give me some extra money so I could enjoy a few simple pleasures like drink a little beer and play a little golf.

All engineering students at the University of Washington took the same basic courses as a freshman, and I still had not made my final decision on a major during that year. As my sophomore year began, it was necessary for engineering students to declare a major. One afternoon, I was talking to some of the brothers, and one important thing for the rest of my life popped out of the conversation. The ceramic engineering department only had about thirty total students, and as luck would have it, there were five of those students in the SigEp house. I decided on that afternoon that I would study ceramic engineering because it would be great to be able to get help from an upperclassman if I ever needed help with the curriculum.

At that time, I did not think through enough to ask about companies that would hire new ceramic engineers. I did not know that there were limited opportunities for ceramic engineering jobs in the northwest. I also had no idea where I might have to relocate to if I pursued a career in ceramic engineering. It has always amazed me that my life could turn so completely on a decision that seemed like a good idea at the time. In retrospect, it has been a good decision and my career has been very gratifying and enjoyable, but I definitely would have enjoyed living closer to my family in the northwest during my career than I was achieving on the path I chose for a career.

I was able to finish all my work for my bachelor of science degree in ceramic engineering during the fall quarter of 1962, except for a thesis that was required for an undergraduate degree in ceramic engineering at that time. I therefore spent one more quarter to complete my thesis, and I graduated with a bachelor of science degree in ceramic engineering in May of 1963. During the winter quarter, as I was finishing my thesis, I began interviewing prospective employers. I interviewed 3M, NASA, Procter & Gamble, and Ford Motor Company. I got employment offers from all four companies and visited 3M in Minneapolis and Ford Motor glass division in Dearborn, Michigan.

Ford Motor Company

After the visit to Ford Motor Company, I decided to accept the job offer from Ford. Today, the numbers are crazy, but my offer was a salary of $575 per month. Obviously things were a lot less expensive then, as apartment rent was about $100 a month. I also bought one of the first 1,000 Mustangs ever made for $3,750. It was a burgundy body with a black convertible top powered by a 389-horsepower engine with a four-speed manual gear shift. That was the first new car that I ever bought, and I really enjoyed that car. So that salary let me enjoy living, and I had some spending money basically for the first time in my life. It did intrigue me later in life that if I had elected to accept the offer for NASA, I would have been involved in the manned space flights and the moon landing. I must say, that would have been amazing, but as I have learned after fifty-five years in the float glass business, my decision to enter the float glass industry turned out well.

Early History of Glass

The first known glass occurred naturally when lightning would strike the ground or a volcano would spew lava onto the ground and fuse the surrounding materials together. If sand was present and the other materials at hand were some kind of flux, then the fusing process would produce a glass called obsidian. There are many varieties of obsidian since the wide assortment of glass-making materials in the world will react to create different properties of any glass beads formed in this fusing process. The obsidian is usually dense and often black or brown and is hard and brittle. The ancient people prized the obsidian since the material was easy to shape into such things as arrowheads, spearheads, or razors. Some more advanced primitive cultures often used the obsidian to create ceremonial masks or jewelry. Humans have always shown a fascination about this material, but early man had no idea how or why the material occurred.

As man entered the Bronze Age, he learned the techniques for firing pottery, which used special kilns for this purpose. Then in time, the kilns were adapted to fire the glazes and produce a colorful addition to their pottery. This technique was realistically the beginning of man unlocking the secret of producing glass.

The story of the first man-made glass was relayed historically by Pliny, a Roman admiral. Pliny tells the story of a group of Phoenician merchants returning from Egypt with a shipload of crude soda. A storm forced the group to spend the night on a sandy beach in Syria. When the merchants could not find rocks to ring the firepit for their cooking pots, they took blocks of the crude soda to line the fire pit. Later when the fire was at its hottest, the merchants observed a strange liquid flowing in a stream from the fire. The combination of sand, soda, and heat had produced glass. This legendary story intrigued a twentieth century student of glass to try to duplicate the feat, and he built a bonfire atop sand and ringed it with soda. Two hours later, when the fire had reached its maximum at 2,210°F, there was no trace of fusing and the sand had not melted. This story may not portray exactly how the first man-made glass was produced, but the glazing work done on pottery was certainly a form of glass and was leading to the discovery of producing glass products.

Eventually, the secret to producing glass was unlocked in Egypt or Mesopotamia. The secret they learned was that the basic recipe for making glass involved three elements. There needed to be a former, a flux, and a stabilizer. The major ingredient, the former, is sand or silicon dioxide (SiO2) or simply called silica. The flux is an alkali, and the most common alkali is sodium carbonate (Na2CO3) or simply called soda. The flux lowers the melting temperature of the sand in the fusing process. The stabilizer provides chemical durability to the glass when added to the batch. The most common stabilizer is limestone or calcium carbonate (CaCO3) or simply called lime. This type of glass produced using these three major ingredients is simply called soda, lime, silica glass.

After the secret was unlocked, many different batch compositions were possible, which would produce specialty glasses when melted. These specialty glasses were very valuable, and it was a very closely guarded secret as to how this glass existed. Those who knew the secret were executed if they tried to escape with the knowledge, or if they escaped, then his family would be killed. Eventually, however, the secret got out and glass production began to occur in places other than Egypt or Venice.

Once the glass production secret was unlocked, it evolved into many different kinds of glass products. I am not going to talk about glassware, hollowware, or any other type of glass than flat glass. My entire career has been in the flat glass side of the industry, and that is what I want to cover in this book. I also am writing these words very late in my life, and my memory of some of the events that occurred may be a little cloudy but true as I remember them.

History of Flat Glass

When I started college, there were two methods of making flat glass on a continuous basis. There were sheet glass processes and there were plate glass processes. Sheet glass products were cheaper to produce and, therefore, were the choice for flat glass installations where visible distortion was not too critical to the naked eye. Plate glass products were much more expensive to produce since the imperfections in the surface of the glass were ground and polished on a huge grinding and polishing line. The grinding and polishing system made the glass sheet virtually distortion-free, so plate glass was the choice for flat glass used in high quality areas like the production of mirrors and windshields.

Crown Glass

The sheet glass production operations in use in 1963 had evolved through four major stages. The first process in this evolution was the crown glass method, which remained in use until around 1800. The next phase was the hand cylinder method, which remained in use until around 1900. The replacement for the hand cylinder method was the machine-blown cylinder method which was introduced in 1903. Finally, the sheet drawing method was introduced in the 1920s, and this process provided the ability to continuously produce sheet glass rather than produce one piece at a time. This innovation was the first big step in the mechanization of the flat glass industry.

The crown glass method used a blowpipe, which was invented around the time of Christ. In the figure below, this method is illustrated. The blowpipe was inserted into a pool of molten glass, and a gob of molten glass was gathered on the end of the blowpipe (1). A worker would then blow through the blowpipe to form a bubble (2). A punty (iron rod) was then attached to this hollow glass ball opposite the blowpipe (3). The glass is reheated so that it is molten, the open end is pulled out (4) and then quickly spun on the rod so that it forms a flat table of glass (5). The tables are then stacked in the annealing furnace to be cooled in a controlled manner (6). Each disc had a bull’s-eye or crown in the center, hence the name crown glass. The crown glass process was a very laborious and lengthy operation, and it only produced small panes or sheets. The sketch below shows the steps in producing Crown Glass.

From Float and Pilkington archives.

Hand Cylinder Glass

Early in the nineteenth century, the hand cylinder method replaced the crown method. The worker blower gathered a lump of molten glass on the blowpipe (1), and this lump is blown into a bubble (2). This is repeatedly reheated, swung in a pit next to the glassblower, and blown again so that the bubble of glass is shaped into a cylinder (3). After the glass has cooled, the ends of the cylinder are cut off, the inside is scored so that the glass cracks (4), and the glass is reheated so it can be flattened by workmen with a wooden paddle tool into a sheet (5). This technique was also a long and arduous process, but the hand cylinder method did make it possible to make larger sheets of flat glass and of course eliminated the bull’s-eye from the panes. The hand cylinder method is shown below.

From Float and Pilkington archives

Machine-Blown Cylinder Glass

In 1903, the Lubber’s machine-blown cylinder method of making sheet glass was introduced, and this process was one of the first big steps in the mechanization of the flat glass industry. In this process, molten glass was melted in a drawing pot and a circular bait (ten inches in