Sandcarved Glass and Kiln Work
Author: Sara Urband-Murphy
Published: May 16, 2002
Revised: August 03, 2005
Combining kiln work with sandcarved glass can add dimension, sparkle and color to your glass art. I will provided an over view of techniques for adding color, fire polishing, fusing and shaping etched glass. To use these techniques you will need to have access to a kiln so I will discuss kiln selection first.
KILNSThere are kilns designed for ceramic use and those designed for glass work. The ceramic type has electrical elements in the side walls. A glass kiln will have the elements in the lid. Both types will actually work for glass. The major difference will be in the rate at which you heat the glass. Top heating kilns can be heated approximately 5% per minute faster than the side heating variety. Some things to consider when selecting a kiln are diameter and depth. This will determine the size of work you can produce. Also consider your electrical supply. There are 110 Volt and 220 Volt kilns. Some kilns fire with a manual cone system. I would suggest also using a limit timer with this type. There are also fully automatic computerized kilns. These can be programmed to increase temperature at specified intervals. There are a number of manufacturers and kiln types available. I will include a list of websites in my resource page at the end of this document. There is also the option of purchasing a second hand kiln from a garage sale or classified add. This is the most economical route and my personal recommendation to those of you who just want to dabble. I purchased a mid-sized electric kiln for $60 that works beautifully. If you purchase a manually operated kiln you will also need to invest in a pyrometer. This will allow you to monitor the speed at which your glass is heating. The cost will be around $90. Enough about kilns for now. On to the fun stuff.
FIRE POLISHING, SLUMPING AND DRAPING
Fire polishing glass will create an effect similar to clear coating but it is a much more permanent effect with no concern of yellowing or pealing over time. A deep cut edge will take on a glow almost as if it were edge lit. Fire polishing occurs at approx. 1150 degrees. I recommend its application to flat work for the most part. Although glass is not really considered to enter the "Fluid Zone" until 1300 degrees, thinner pieces such as glassware will start to bend and twist at lower temperatures. Which brings us to the subject of intentionally bending and twisting glass. As previously stated, this will begin to occur at around 1300 degrees. Glass can be slumped into or draped over a variety of materials including ceramic molds, stainless steel (I have used mixing bowls and colanders) and moldable ceramic fiber "blanket". All molds and kiln shelves will need to be coated with a kiln wash suitable for glass work. This keeps the glass from sticking to the molds or kiln shelves. Kiln wash is commercially available at most art glass shops and in glass supply catalogs. It is best to apply kiln wash to your molds and shelves as evenly as possible. As the glass becomes soft it will take on the texture of the surface it is laying against. A smooth finish is usually preferred but you can also apply the wash to create desirable textures. A cross hatch application of kiln wash, for example, can give your glass the texture of fine linen. For the smoothest surface possible there is a product called shelf paper. It is about the thickness of poster board but is suitable for high temperature use. Its cost is around $3 wholesale, for a 20"x20" sheet and is available through art glass suppliers.
NOW LETíS ADD SOME COLORYou can add color to your work through the use of glass paints, powdered enamels or fused art glass. Weíll start by discussing the glass paint option.
There is the glass paint you get at your local craft shop that can be baked in your oven at around 275 Degrees. I have found the results of this product to be very disappointing. Some of the colors donít stay true. The color is often uneven and the finished texture looks sticky. I would recommend passing on this option. The type of paint I use is Unique Glass Colors. An instruction sheet for application will be provided by the manufacturer when you purchase the paints. They are a pre-mixed paint similar to that used for painting the faces and other fine details in church windows. There are a variety of opaque, semi-transparent and transparent colors available. Additionally each of the 3 types are compatible for mixing within their own group which greatly extends the color pallet available. The cost is around $3 per 2oz bottle. The website will be available on the resource page. This paint works well on etched glass when applied in a pooling technique. It naturally follows the lines of the carving. Any paint inadvertently applied to smooth areas of the glass can simply be whipped away with a finger or a soft cloth after it has dried but prior to firing. Firing temperatures are between 1330 and 1465 degrees. Try to stay to the lower end of the firing scale. Your glass will begin to loose its etched work at the higher temperatures.
These paints are similar to ceramic glazes in that their color prior to firing is different than the finished color. I recommend making yourself a glass chart of all of your fired colors for easy reference when making color choices for your work.
Lets touch briefly on enamels. I say briefly because I havenít tried them personally although I intend to very soon. Enamels are highly pigmented, finely crushed glass powders. They have a more intense color than the glass paints. Small amounts will create brilliant effects. Fuse Master enamels are compatible with all glass manufacturers and can be painted, sifted or airbrushed. I discovered them after the workshop but felt they should be included in this segment. They are available in opalescent and transparent colors. The firing temperature of the opalescent colors is 1300 to 1550 degrees. The transparent variety will probably be the best option for use in conjunction with glass carving due to the lower firing temperatures of 1080 to 1175 degrees.
Onward to fused glass. Compatible glasses can be fused together to create some fantastic colored, carved, shaped glass art. Your imagination is the limit to the possibilities. Because glass is fused at a relatively high temperature it is necessary to do your fusing prior to carving your pattern. I have fused together compatible glass colors, turquoise over purple, for example. I then carved through the darker color, purple in this case, back to the lighter, turquoise. The result is a carved design with subtle shades of blue and lavender floating on a deep purple back ground. Are you getting the picture? Now imagine for instance a 12" disk of cobalt blue glass fused to a 12" disk of emerald green glass, a trail of ivy deep carved around the perimeter through the blue to reveal many shades of blue and green. Now take this disk of ivied glass and place it over a floral former (an inverted vase type of glass mold) and fire it once again. This would be a draping technique. The end result is a beautiful vase with a ruffled edge adorned with a variegated trail of ivy, Galle would be jealous of your exquisite creation. Now, go out and buy a kiln. Run!
In closing I would recommend purchasing a book on basic glass fusing. There are several available. I have The fused glass handbook by Gil Reynolds. Also get on the warm glass website. There is certainly a lot of technical information available that I have not touched on. Have a Blast!
Kilns:L&L Kiln MFG
8 Creek Parkway
P O BOX 1898
Boothwyn PA 19061
877 455-5456 toll free
6949 Legion Rd
Caseville MI 48725
Skutt Ceramic Products Inc.
6441 SE Johnson Creek
Portland OR 97206
Blue Diamond Kiln Co.
P O BOX 172
Metarie LA 70004
350 SW Wake Robin Ave.
Corvallis OR 97333
Misc. Supplies:Delphi Glass
3380 E. Jolly Rd
Lansing MI 48910
11780 N. Dale Mabry
Tampa FL 33618
Zircar Refractory Composites Inc.
( This is the source for moldable wet blankets to make custom slumping molds.
Go to the website. In the left column, search by product, scroll down to art glass materials.
This is where you will find the products you need.)
46 Jayne St.
P O BOX 489
Florida NY 10921-0489
Unique Glass Colors
Kiln Fired Glass Paints
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