Rolled glass is manufactured by pouring glass from the furnace into a series of rollers. It is then shaped to the desired thickness, annealed and cut to size. The two basic types of rolled glass are patterned and wired. Patterned glass is also called figured glass, obscure glass, and decorative glass.
Rolled glass is made by pouring molten glass on metal sheets and flattening it with a large roller. The glass is annealed or cooled slowly so it doesn't become brittle. Some rolled glass is made on a double roller table, which presses the molten glass between two rollers.
Three very important types of glass are annealed, tempered and laminated glass.
Most of this glass appears in homes from 1870 to the 1930's. You can still see the wavy nature of this glass as there still striations as the glass was lifted. After industrialization, the process and methods for making glass didn't change. However now machines made the process more efficient.
Tempered glass, also called safety glass, is the smartest choice for windows and other glass structures in your home. Tempered glass is heated and then cooled very quickly during the manufacturing process; this rapid change in temperature makes it about four times stronger than untreated glass.
While some people believe that the waviness is the result of the glass warping over time, the real reason for the wavy appearance has to do with the way glass was made at the time the home was built. There are two types of glass that were used in the 19th century: crown glass and cylinder glass.
For between $5 and $50, you can often walk away with some old glass. how much you'll spend just depends on the size and waviness of the glass. AGW makes some great wavy glass in several different grades of waviness to help you match the glass to the age of your project.
Properties of Wavy Glass
The distortion and imperfections appear when looking at the glass from angles or looking straight through it. The earlier the glass was produced, the more likely it will have small seeds or pits and heavy cords (reams) throughout.
“Annealed glass” is basic glass manufactured using the standard float glass process. All glass made for windows, doors and skylights in North America is manufactured by the annealed process. This is also known as annealed glass unless it is subsequently heat treated.
Sheet Glass is the most common type of glazing glass available in the market today. Initially, it was formed in plane form. It is typically used for transparent walls, windows, windshields and glass doors.
Rolled Glass
There is little cost difference between rolled and float glass. Rolled glass is special due to its macroscopic structure. The higher the transmittance the better and today high performance low iron rolled glass will reach typically 91% transmittance.
A mosaic is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and were particularly popular in the Ancient Roman world.
Float glass is considered by most to be of better visual quality and easier to transport and fabricate than sheet manufactured glass. The float process also allows for much larger sizes for thinner glass products.
You'll most often find wavy windows in homes built before the 20th century, although glass doesn't get wavy overnight. Slowly, the glass in homes built in the early part of the 20th century will also begin to feature this unique distortion. It's somewhat of a myth that wavy windows are due to sheer age.
Contrary to the urban legend that glass is a slow-moving liquid, it's actually a highly resilient elastic solid, which means that it is completely stable. So those ripples, warps, and bull's eye indentations you see in really old pieces of glass “were created when the glass was created,” Cima says.
Cylinder Glass and Crown Glass are two types of authentic, mouth-blown antique window glass typically found in historical structures in the United States. Both types employ a blowpipe to shape the molten glass.
Tempered glass units are heat-treated in a horizontal oven and contain waves created when the units come in contact with the rollers during the heating process. This waviness, known in the industry as roller wave distortion, can be seen when looking at a reflected image on the glass from a distance.
Cylinder Glass
It's also known as wavy glass for the bubbling, undulating imperfections found in the surface of the glass that distort images when you look through it.
Crown glass is a type of optical glass used in lenses and other optical components. It has relatively low refractive index (≈1.52) and low dispersion (with Abbe numbers around 60).
High-rise buildings use heat-strengthened glass instead of tempered or laminated glass to help withstand pressure and suction forces from the strong winds. Also, it allows for the retention and insulation of heat.
soda-lime glass, lead glass and borosilicate glass. These three types of glass make up around 95 percent of the cullet glass used in the production process. The remaining 5 percent of glass is special-purpose glass.
Laminated glass is a type of safety glazing constructed by uniting two sheets of glass with a sturdy interlayer and applying heat and pressure to create an inseparable bond. via GIPHY(↗) This process makes the glass less likely to break out of the frame and it's less of a threat when broken.