Terminology for Glass, Etching, Sandblasting & Sandcarving

Glass *: Scientists differentiate glasses from crystals and metals by the way that the atoms arrange themselves as they cool. Both crystals and metals form structured atomic bonds as they cool and solidify. These bonds are always arranged the same way.
Not so with glasses. Glasses form the same kind of bonds as they cool and solidify as they have when they are liquid. These bonds are not structured, but random, whether the glass is in a state of high viscosity (flows easily) or low viscosity (flows not at all). For this reason scientists classify glass sometimes as a super-cooled liquid, or as an amorphous solid. And rather than a melting point, it has a point at which it will soften and flow when it is heated enough, or it will thicken and become rigid when it is cooled enough.
There are many types of glass. Some of the types that are more pertinent to this web site are...
  • Lead-alkali glass (crystal) contains lead oxide, which produces a glass of exceptional beauty and sparkling clarity that is also soft and easy to etch. It is also fragile and will scratch easily. (Lead crystal is not crystal at all! This is a misnomer that was given this type of glass because of its similarity in appearance to a crystal.)
  • Stained glass (also know as art glass) contains small amounts of certain elements that give it color, such as chromium for green, cobalt for blue, or cerium for yellow.
Etching: This term is both a noun, describing something that was etched, and a verb describing a process. To understand the end product (noun), we must understand the process (verb). Etching is simply a way of scratching, abrading, or impressing a, usually hard, surface to form some sort of imagery on that surface. Etching may be done using acids on the surface of glass, for instance. All the etchings referred to, or shown, on the Riordan Artistry web pages are created using sand-blasting and sand carving.

Sandblasting: This is the etching of glass, or other material, by slamming high-speed particulates (sand, etc...) against the surface of the material. The force required to slam the particles is generated by an air compressor.

Sandcarving: This process takes the sand-blasting process to an art form by allowing the sandcarver to cut and shape glass in three dimensions. A sand-carving has much more appeal than the typical surface-frost sandblast, but is also much more time-consuming and costlier to produce. A sand-carver is usually an artisan of considerable skill.
Do we do deep, multi-stage, and variable depth carving? In a word, yes.

A picture is worth a thousand words.

The glass is 3/8" plate glass. The sandcarving here goes more than 2/3 the way through the glass in some places.
This view shows an ultra-detailed border on the other side of the glass from the butterfly and rose.

This piece is not a rounded out design, but actually a piece composed specifically to illustrate the alternate, yet complementary, sandcarving techniques that Riordan Artistry has in its arsenal.

  • The rose is a deep-cut, variable-depth carving on the back of the glass.
  • The butterfly, also on the back, is a multi-staged carving, which also features variable-depth cuts in the wing patterns.
  • The decorative border, on the front of the piece, is a single-staged, ultra-detailed frosting. The definition here is unsurpassed in the industry. And although the detail resolution may be rivaled by laser cutting techniques, lasers yield no depth, and certainly no variable depth.

Do we do photographic or gray-scale rendering?
Why yes! See picture to the left, as well as the Wedding & Anniversary, and Illuminated Works sections.
 

Stained Glass Types (We sometimes etch stained glass, or etch glass within stained glass compositions)

  • Machine-Rolled:  Highly consistent in size, thickness, and color. Typically the molten glass is double-rolled by a pair of counter-rotating metal rollers. Sheet sizes are generally much larger than hand-ladled glass.
  • Mouth-blown / "Antique":  Made in the traditional manner by highly skilled craftspeople. A "gather" of molten glass is enlarged to a cylindrical shape on the end of a blow pipe. Next, the ends are cut off. Then the Cylinder is cut length-wise before reheating to flatten into a sheet. The unique coloring and linear striations are characteristic of mouth-blown sheets. Most is made in England, Germany, or France.
  • Mottled: Glass with areas of opaque and translucent spots of color. May be one, two or three colors per sheet. Well suited to organic and three-dimensional imagery.
  • Opalescent: A semi-opaque glass of milky or marbleized appearance. It was used in the Victorian art glass work and in the "stained glass" windows and other glass decorative articles produced by Louis Comfort Tiffany. Today it is used extensively in Tiffany-style lamps and windows.
  • Streaky: Multi-colored transparent glass, usually smooth on both sides.
  • Waterglass: A texture achieved by stretching hot sheets; resembles the gentle ripple of water.
  • Hammered: A rolled texture of small round, smooth bumps on the back surface of the sheet.
  • Iridescent: Made with a technique that gives the glass surface a metallic sheen, or mirror-like effect, which reflects the rainbow of colors. This gives life to what would otherwise be a dull surface without back-lighting. The glass retains its normal color transmission. Some types of iridescent glass sell for in excess of $150 per square foot.
  • Craquel: Prior to the blowing, this glass is quickly dunked in oil or water which cools the outside, but not the central core. The resulting surface of the glass is similar to an alligator skin. It has an interesting and random look.
  • Seedy: A slightly textured glass in which air bubbles are trapped to give the glass an extra sparkle (like Champagne).
(*) Introductory glass definition paraphrased from A&E Magazine, Sept. 1996 issue.
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