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.
1. Buy New Wavy Glass - We can source the glass from a vendor the reproduces "handmade" glass using modern techniques to create the historic look. There are a few popular places that sell new old style wavy glass, Artisan Glass Works (AGW), Hollander Historic Glass, and Bendheim 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.
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.
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.
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 is one type of antique, mouth-blown window glass found in historical buildings dating back to the 1600s. 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.
The texture is created during the glass sheet-forming process. A sheet is formed from molten glass with a roller that spins on itself, while travelling forward. Normally the roller spins at the same speed as its own forward motion, and the resulting sheet has a smooth surface.
According to AntiqueBottles.com, bubbles are rare in glass produced after 1920, so the presence of a bubble may help to date a bottle or window.
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.
Sash Windows
Each of these type of antique windows usually has wood sashes, also known as muntins or lites, that framed the window and held the individual panes.
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.
Drawn antique glass (also referred to as “GNA”) is also wavy glass with lines, but no “bubbles.” It is popular in cabinet doors and china cabinets.
Any source of alkaline will do, ammonia, caustic soda, baking soda and even spit will greatly help in the cutting of glass. Old secondhand window glass is notoriously difficult to cut straight.
To create the wavy glass look, squeeze out a little of the window coloring and spread around with a spoon to create that wavy texture. Though it's white while wet, it dries clear! You can either go with a traditional texture or get creative and make up your own geometric patterns with the coloring!
James Hartley was granted a patent in 1838 for producing glass made by casting the hot glass 'metal' onto an engraved surface and then rolling it from above.
If you look at glass in old windows, it can look distorted, apparently because the lower part of the pane is thicker than the upper part. Some people think that's because the glass, which behaves like a liquid at times, has sagged over time due to the effect of gravity. But scientists see through this myth.
Rain Glass, an addition to the Obscure Glass line from MI Windows and Doors, has a pattern that resembles water trickling down a smooth sheet of glass. Beyond the visual effect, the glass provides privacy and diffuses light, while resisting stains and fingerprints.
How Glass Was Made in the 1800s. By the late 1800s, glass was being made by blowing a very large cylinder and allowing it to cool before it was cut with a diamond. After being reheated in a special oven, it was flattened and affixed to piece of polished glass which preserved its surface.
Guardian Glass. An optical phenomenon, generally noticed in reflection, caused by hot glass sagging between rollers in the horizontal toughening process. Also referred to as 'banding', 'corrugation' or 'wiggle'.
Roller wave distortion is a condition found in heat-treated glass that causes the glass surface to have imperfections known as peaks and valleys. These alternating high and low points result in the glass exhibiting optical distortion. Most noticeably, images reflected in the glass appear to be rippled.
To make sure your rooflight can handle such conditions, always use toughened glass. Also known as tempered or safety glass, toughened glass is the quintessential glazing option for various fenestration solutions. This is because it is 4-5 times stronger than standard glass or annealed glass.