Brilliant Cut Glass: Engraved Decoration for Doors and Windows
by Tomas Tisch
During the Victorian Era, many homes as well as places of business were embellished with a unique type of ornamental glass: brilliant-cut glass. Sometimes called wheel-cut glass (after the tools used in the process), this beautiful and elaborate technique was usually reserved for prominent display in entrance doors, sidelights, transoms, or interior doors. Designs ranged from simple geometric patterns and star cuts to more intricate florals, some featuring foliage, baskets, bits of architecture, and bird motifs. Commercial applications included fancy lettering and numerals. All were intended to demonstrate the refined taste of the owner.
Cutting Edge History
Grinding, cutting, and polishing are about the oldest techniques used to shape and decorate glass. The ancient Egyptians were already cutting glass 4000 years ago by using tools adapted from lapidary (gemstone) work. Simple forms of brilliant-style cutting were practiced almost as soon as plate glass was invented in France in the 17th century. At that time, most plate glass was used to make mirrors, which were an extravagant luxury. The early manufacturing process was capable of producing only relatively small units, so in order to cover greater areas two or more panels were mounted in one large frame. Glass cutting was used to decorate and disguise the mounts where panes met. Soon, the uncomplicated geometric designs of early cutting evolved into more elaborate patterns. These techniques, developed for plate glass, were used later in the 19th century to cut window glass. Most Victorian brilliant-cut glass was produced on frosted rather than clear glass because the polished cutting looks more dramatic. Many outstanding examples of the art still survive.
The basic techniques of brilliant-glass cutting have changed little over the centuries. Abrasives have improved and machines are now powered by electric motors, but cuts are still made by hand without guides or templates, and the artist must rely on patience and skill.
To duplicate a design, one starts by taking a rubbing of an original panel. (If the original glass is lost or the piece is a new door or window, graphic elements from existing period glass can be adapted to create a design in an appropriate style.) Afterwards, the artist transfers the piece of frosted glass by carefully tracing the rubbing. (Frosting is accomplished by abrasive grinding or by acid-fogging. Sandblasting is not used because it leaves a pitted surface.)
The actual cutting is done with a tool called a glass cutting lathe. Like a bench grinder, the glass cutting lathe is one or more vertical wheels mounted to a horizontal shaft driven by a motor. The edge of each wheel is shaped to a specific profile: flat, miter (V-formed), and round. The profiles can be shaped to varying degrees, with one that is just a little rounder than the next used for quite a different cut.
Some designs can be executed with just one stone. By knowing which part of the wheel to cut with and just how to pull the glass, the experienced artist can produce a variety of very different looking cuts. However, even the most skilled craftsperson cannot produce all designs with the same tool.
A complete shop will have at least 20 stones ranging from 2" to 30" in diameter and 1/4" to 2" inches in thickness, and often many more. Originally, cutting wheels were made form natural stone, particularly, the carboniferous sandstone quarried at Craigleith, near Edinburgh, Scotland. Natural stones are still being used today, but man-made materials such as aluminum oxide are more durable and uniform and can be produced to the specific needs of cutting.
The cutting process is a very delicate one. The glass is incised to a depth of 1/16" at most, and a light hand is required to guide the panel over the wheel. The glass must be handled fluidly, to achieve graceful lines, but also surely enough to maintain control. Panels can be 4' or more across; even with the aid of a counterweight to suspend the glass, cutting becomes a formidable task. Each cut must be cooled by water applied from a small hose and spread to the wheel by a sponge attached to a board. Cutting alone leaves the design very smooth and translucent, but not yet "brilliant", and is sometimes used to achieve beautiful effects, especially in combination with highly polished areas.
In most cases, though, the entire design will be polished. The wheels used for polishing are similar to the ones used for cutting, but need to be relatively soft and porous to hold the polishing compound. Most are made of wood or cork; the polishing agent (pumice polish mixed with water) is applied to the wheel. Every cut must be polished individually. After the pumice, one final polish is needed to give the glass its brilliance. For this step, a soft wool felt wheel coated with cerium oxide is used. This modern polishing powder works fast and gives the glass a perfectly smooth and sparkling finish. After polishing the panel is cleaned. Some touchup may be required, but now the panel is ready to be installed.
Reviving Found Art
During restoration, some lucky new owners may discover wheel cut glass in pocket doors or transoms hiding under layers of paint. Careful cleaning along the following lines will restore these treasures to their former glory:
- To remove dirt and grime, a simple soap-and water solution still works best.
- Do not use abrasive materials of any kind when cleaning. Avoid scrubbing with steel wool or cleaning pads as these, too, will scratch the panel's surface.
- To clean painted-over windows use a good-quality paint stripper. Work gently with brushes, cloths, and plastic spatulas rather than scraping with sharp implements such as metal putty knives.
- During cleaning one may discover broken panels or sections that have been replaced with regular glass. The cost of replacing a brilliant-cut window depends primarily on the design, but factors such as removal, reinstallation, and the size of the panel also come into play.
In our fast moving world, the beauty of light reflecting and refracting individually polished brilliant cuts is well worth preserving.