The Art and Science of Etched Glass
One of the simplest ways to change the look of a piece of glass is to etch it. Etched glass is formed by the removal of tiny particles of glass from the surface of the object. The picture at right shows the surface of some etched glass magnified 200 times. Etched glass will look frosted since light is transmitted and reflected from an angled surface in proportion to that angle. A rough etched surface has many angles, so light is greatly distorted by this surface. These properties can be used by the artist to obscure and shade glass surfaces in many ways.
While much etched glass is simply a shallow pitting of the surface, glass can be etched deeply too. Glass that is etched at different depths is called “glass carving” – and is an art all to itself.
Etching can be used as the main technique for a glass art piece, as in a window or door that has been etched with a unique design. (See our gallery for some examples.) Etching can also be used in conjunction with fused or stained glass. For example, we often use etching on fused glass pieces to simply give the piece a matte texture instead of a glossy one.
There are two main categories of glass etching techniques, one using chemicals and the other using abrasives. Chemical methods use either an acid or a floride paste to remove the top layer of glass. Abrasives can be used to scratch or pit glass in several ways. Glass can be sanded, ground or carved with standard sandpaper and rotary tools. It can also be “sand blasted.” This technique uses very hard abrasive particles, blown at high speed onto the glass, to create microscopic chips in the surface. Executed properly, all these processes will result in beautiful designs, but it is mainly the sand blasting process that is used commercially for etching and glass carving. (Learn more: See the Wikipedia article “Glass Etching”.)
At Renegade, we etch glass by sand blasting using specialized equipment in our sand blast booth. To begin, we protect the areas that are not to be etched with a “mask.” A mask is typically a piece of vinyl with a strong adhesive that has been cut to the shape defined by the artist. The mask may be a simple outline or may have multiple layers that can be exposed in succession, resulting in a more complex shading of the design. The masking of the object must be painstaking – any area exposed or potentially loosened by the high pressure air and abrasive will be permanently etched. Once masked, the piece is placed in the booth. Our booth is a “glove box,” meaning that the operator stays outside the booth yet places her hands in gloves that are attached to the wall of the booth. This keeps the operator’s skin, as well as eyes and lungs away from the airborne abrasive and glass dust. After the blasting is done, the piece, with mask still attached, is carefully cleaned. This is critical also, since any abrasive remaining on the piece could cause an inadvertent scratch. When this is complete the masking is removed and the piece can be cleaned further. Some pieces are put through a final step, that of sealing the etched area to prevent dirt (particularly fingerprints) from contaminating the etched area.
If you’d like more information, or would like to discuss a custom etched glass project, please contact us.