Glass by Kathi stained glass supplies & classes
© 2001-2007 Katherine Bell © 2001-2007 Katherine Bell
glass by kathi home page glass by kathi gallery glass by kathi pricing glass by kathi services glass by kathi frequently asked questions glass by kathi classes glass by kathi contact us glass by kathi links

Frequently Asked Questions

How should I measure my windows for an installation?
Please read Measuring and Installation Guidelines for detailed information and illustrations.

How long will it take to make my windows?
The entire process can take from three weeks to six months, depending upon how many orders I have on the waiting list, how quickly we work through the commission/design process and the complexity of your project. If you have a special event you are planning for, I will make every effort to help you meet your goal. The Holidays are always a very busy time... so get your orders in early!

What if I move? Can I take my glass with me?
In a word, YES. Please read Measuring and Installation Guidelines for information and illustrations.

Some "Glass Facts"

Composition and Properties of Glass
Humans have used glass since prehistoric times, making small objects out of natural glass, such as obsidan (a volcanic rock) or from clear rock crystal. By definition, glass is a vitreous* solid material made by fusing silica (which is obtained from beds of fine sand), sodium carbonate (to lower the melting point) and lime (to stabilize the mixture).

As this mixture is melted, secondary materials, usually in the form of oxides, are added to change the properties of the glass. For instance, lead is added for brilliance and weight; barium helps increase the refractive index; and metallic oxides provide color. Some of the most commonly used additives and the colors they produce are listed below.



Green, brown, blue




Green, yellow, pink


Green, blue, grey


Blue, green, red


Blue, green pink


Yellow, purple

Cadmium Sulphide



Purple, brown



Carbon & Sulphur

Amber, brown


Pink, red



* Vitreous refers to a material in a glassy state. In such a state, the constituent atoms do not exhibit the long-range order that is characteristic of crystals. However, they still exhibit short-range order -- the separation of atoms and/or the lengths of covalent bonds are very close to their typical equilibrium distances.

Types of Glass
Stained glass fabrication utilizes many different types and styles of glass, with a vast array of colors, textures and degrees of transparency. Sheet glass is often by differentiated by how the sheet is formed, such as "mouth blown," "double-rolled", "hand-rolled", etc. Other types of glass include bevels, globs (or nuggets), jewels, rondels, etc.

Mostly made as a single color glass. This transparent glass is primarily a machine made glass and comes in a variety of textures.

Mottled (or Ring Mottle)
This type of glass is most identifiable with Tiffany. It is also known as being the most difficult type of glass to create. It has a characteristic ring of opalescence, also called ring mottle, which gives the glass a three dimensional appearance and is popular for use in lampshades.

Opalescent Glass
Semi-opaque, with a milky appearance. Opalescent glass can be one solid color or a mixture of two or more colors with streaks and swirls. See also Streaky and Wispy.

Streaky Glass
Made from stirring together two colors of glass, generally both opalescent type glass. The streaks produce another dimension to the artistic impression of the glass.

Translucent Glass
Transmitting light but with diffusion so as to eliminate the perception of distinct images. If you place your hand behind translucent glass, you can see it's shadow but can't see any of the distinct features.

Wispy Glass
Made from stirring together two colors of glass, generally one opalescent and one cathedral type glass. Similar to streaky glass, but to a lesser degree since cathedral glass is generally the 'background' glass.

Glass Textures

(A) Rolled textures: In rolled glasses, one of the forming rolls is embossed with a texture that is imprinted on the glass as the sheet is formed. This produces glass smooth on one side and textured on the other. Common examples are "catspaw," "hammered," "granite," and "muffle."

(B) Natural textures: any textural effect created without mechanical influence or embossed rolls. Includes Baroque™ and Waterglass®.

(C) Cold glass textures: this category includes glue chipping, etching, sand blasting, and any other surface treatment performed on the cold glass sheet at room temperature.

The surface texture of a type of glass can be applied to either cathedral or opalescent glass.

Antique glass can be categorized into three types - Full Antique (Mouth Blown); Drawn Antique (Semi-Antique); and Scribed Antique. Mouth blown glass is the traditional way to produce a full antique glass and relies heavily on the craftsmanship of a master glassblower. This glass is made by blowing a large cyclinder of glass. The ends are then cut off and the cylinder is split lengthwise and flattened to form the sheet. See also Flashed Glass and Drawn Antique.

Often called "semi-antique" or "scribed antique" this is a double-rolled, machine-made glass which resembles very expensive, hand-made "antique" glass. Artique® is a Registered Trademark of Spectrum Glass Company.

A wildly swirled textured glass, most often made of light colored cathedral glass or a combination of a darker opalescent color swirled into a light cathedral background glass. Also used where a special effect is desired. Baroque® is a Registered Trademark of Spectrum Glass Company.

Craquel or Crackle
A mouth blown cylinder that has been dipped in liquid to cause random fissures in the glass and then reheated and further blown to heal the fissures, leaving a unique texture on one side.

Drapery Glass
This opalescent type glass is formed by passing hot sheets of glass through machine rollers. The top roller moves faster than the bottom roller so the glass bunches up forming a drapery effect.

Drawn Antique
Molten glass is drawn vertically from the furnace to produce the sheets of this type of glass. It is then passed through rollers as it cools which leaves striations in the surface of the glass. The resulting glass looks similar to mouth blown antique glass.

Flashed Glass
A type of mouth blown antique glass that has two or more layers of different colored glasses. Usually a heavy heavy base layer is covered with a thin layer, a flash, of another color. This flash can be engraved, etched or sandbalsted to create designs or the appearance of shading.

Fractures and Streamers
The fractures are thin pieces of glass that are created by breaking thin glass bubbles into small pieces. The streamers are simply thin rods of molten glass that are stretched. These fractures and streamers are spread on the rolling table and become fused to the back of sheets of clear or white opal glass.

Glue Chip
A clear or colored glass that is sandblasted on one side. Animal hide glue is applied to the roughened surface. As the glue dries and contracts, chips of glass are pulled off the sandblasted surface producing a pattern with a "fern-like" effect. Double glue chip is created by repeating the process a second time.

This texture has a very heavy random bump pattern on the surface. Light diffusion and distortion is extreme.

A surface texture similar to hammered brass or copper. Small, round, smooth bumps applied to one surface of cathedral glass.

Not a surface texture, but a special surface finish that makes the glass look as if it is coated with oil, creating a rainbow effect. Darker glass colors produce the most distinct rainbow colors. The highly reflective surface characteristic of this type of glass can be found on both cathedral and opalescent glass.

This texture has a very heavy random line pattern on the surface. Light diffusion and distortion is extreme.

Rough Rolled
A very common surface texture. This is a very slight texture added to the surface with a rough roller while the glass is molten.

A surface texture used on cathedral glass, which also runs through the interior of the glass. Small, air bubbles are trapped in the glass.

Its surface resembles the rippling effect of water in light wind. Used most often for background glass where a very light texture and medium optical distortion is desired. Waterglass® is a Registered Trademark of Spectrum Glass Company.

Other Types of Glass

A piece of 5mm thick clear or glue chip glass that has a 1/2" wide beveled edge. Bevels come in standard shapes such as squares, rectangles, circles and ovals. Clusters of beveled pieces are very popular for use in doors, sidelights and transoms.

Glass Nuggets or Globs
Glass nuggets or globs are rounded pieces of melted glass that have a flat back and a dome top. They are irregular in shape, from oval to round, and come in small (3/8"), medium (9/16"), or large (1"). Can be sometimes used in place of jewels.

These pieces of glass are formed by one of two methods. The most popular jewels are formed by pressing molten glass into molds. The more expensive method to make a jewel is to hand cut and polish each facet of the jewel. Jewels are available in round, square, oval or tear drop shapes and in a variety of colors. They are used extensively as accents in Victorian windows.

Brillant handspun circles of glass. These circles are available in various sizes and colors.

Home | Gallery | Pricing | Services | FAQs | Classes | Contact | Links

Copyrights: Unless otherwise noted, all designs are ©2001-2009
by Katherine Bell. All Rights Reserved.
Glass by Kathi, LLC

Please see our Privacy Policy.

Site Last Updated: Saturday, March 27, 2010 11:06 PM