Notifications
SURFACE VARIATIONS
SALT GLAZE
Salt should not bde used in an enameling kiln. It may affect the inside of the chamber and future firings. However, a salt glaze can be fired with a torch. Thicker gauges of copper respond to this better than foil does, but propane seldom generates enough heat to fuse the enamel on heavy copper. Acetylene will work on heavy copper, but all safety precautions should be observed when using the gas.
To begin experimenting, apply a thin coat of liquid enamel to a panel of copper (about 20 gauge, B & S). Sprinkle salt irregularly over the enamel. Allow the coat to dry and fire it with the acetylene torch. The effect will be rough-textured and speckled, similar to the potter's salt glaze. Used with various enamels, dry or liquid, salt glaze produces tones of color which can be adaped to vigorous compositions.
Salt glaze can be fired on copper foil with a propane torch. However, the application of heat is hard to control on thin copper, and with too much heat the salt may melt and the speckled appearance may dissolve into a dirty, caramel color.
COPPPER NITRATE GLAZE
Dark green fern-like, radial patterns with a soft texture may be made by dripping a solution of copper nitrate into wet or dry, white liquid enamel. Depending on placement of the chemical, coloration and pattern will fire out unpredictably as distinct circles or as interconnected webbing. Use a solution of water and copper nitrate crystals (approximately 1:1 by volume) dropped from an eyedropper or from a straw used as a pipette.
When the solution is dropped on wet or damp liquid enamel and the work is fired wet, it will create small, black craters. The edges of the craters will bubble and spread in halos of soft blue. The interiors will be a satiny black. This pattern can be overlaid with transparents for subdued colorations.
If the copper nitrate solution is dropped on a dried, liquid enamel surface, keep the application of each drop at least an 1 inch apart. You may also place a tiny crystal of copper nitrate in the center of each drop to increase the pattern's intensity. Let this applied solution dry for at least 24 hours before firing the piece. If the climate is damp, let the work dry outdoors and the copper nitrate will feather and link its borders among the drops and crystals, If you wish to create the interconnected webbing and the weather is dry, spray a fine mist of water on the piece every 4 - 6 hours for at least a day, letting the work dry between each watering and for six hours after the final dampening.
Firing the copper nitrate solution may produce noxious fumes which can cause respiratory illness and nausea. The fumes vary according to the size of the piece and how much copper nitrate is applied. To fire the solution without problems, try to place the kiln out of doors, or at least near an open window. Do not use this techniuqe in an enclosed space. A fan may be placed near the kiln and used to blow the fumes out of the area. During the firing, if the odor becomes strong, unplug the kiln and immediately seek fresh air. Do not inhale the fumes. If you must remove the work from the kiln, do so holding your breath. Do not re-enter the room unti lthe metallic odor has gone.
ACID LUSTERS
Soft enamels, or low-firing enamels especially reds, will take on a rainbow hue when they are fired lightly in the kiln and then submerged in a nitric acid bath (1 part acid to 2-4 parts water). A long exposure will dull the red color. A 2-3 miute bath is long enough to develop an acid luster without hurting the color and cutting the surface of soft enamel. Remove the piece fro the solution, wash it, and neutralize any traces of acid on it in a household-detergent bath. Rinse well and let it air-dry.
After the work is dry, a luster should have formed. If not, repeat the procedure. This rainbow coloration is also an almost certain by-product of acid cleaning a foil inlay that has been fired on enamel. If you wish to remove the luster, refire the inlaid work very lightly and then clean the new firescale on the inlay with vinegar and salt, instead of exposing it to stronger acids.
MAT SURFACES
Special enamels are manufactured which produce a mat or satin-mat surface, and enamels in general use may be dulled with acids, and commercial preparations. Some brilliance may be lost this way, but accents or overall mat textures may become an important design element, both visually and tactually.
The surface glow of soft enamels will be cut by placing them in a mild, nitric acid bath, although prolonged exposure to the acid may make them vulnerable to staining. For work that will not be handled often, this is not important.
As an alternative, undiluted hydrofluoric acid can be swabbed onto the enamel surface, but it must be used with caution; it must be kept in the bottle in which it is sold and must never be put in glass containers, for it eats through glass. Fumes are very toxic and can also damage the surface of eyeglasses worn near them. Skin contact should be treated at once with soap and water or with whiting. Experiments for this book were made outdoors; rubber gloves were used and the acid was applied to the enamel with a tightly rolled swab of cloth tied onto a long stick. The swab was dipped into the bottle of acid and applied to the enamel from a distance. (The enameled copper was placed on a thick layer of newspapers). A layer of broken-down enamel developed in a few moments. Rubbed away with the swab, it showed the mat surface was ready. The work was then picked up with 2 wooden spoons dipped into a plastic dishpan of water nearby and then rinsed under running water. Selected areas of the enamel can be blocked out with resists of etching asphaltum or warm beeswax or paraffin, to preserve their gloss.
There are simpler and less hazardous methods to produce mat surfaces. Enameling suppliers have a mat salt, which is easily applied in a paste form to the enamel. When the paste is washed off, a soft, mat surface appears. There is also a mat enamel which, when applied to fired enamel and fired, will diminish the gloss without changing the color of the enamel underneath.
Another method of obtainig a mat surface is to grind down an enamel with a carborundum stone and water, finish it with emery paper or cloth and finally polish it with powdered pumice mixed to a paste with water. In preparation for painting or brush drawing on the enamel, rubbing the surface with emery cloth gives it a "tooth" that takes the painting medium well. The emery dust should be washed off first. A gloss will return to the surface when the panel is refired to fuse the painted enamel. After this, a mat surface may again be made by any of the methods just described.
PATINAS
A soft blue-green film will gradually develop on copper from chemicals in the atmosphere when the metal is exposed outdoors. If time does not permit waiting for natural patinas, treatment made with metal colorants can give a number of effects. There are many formulas in books on metal-working and solutions are sold commercially by metal and enameling suppliers. Foil inlays and copper exposed by flooding, sgraffito, ripple or cantaloupe skin, lecithin granules, firescale irregularities, and stencils may be colored. A basic rule is that the metal must be very clean for solutions to give specified effects. Following are simple mixtures used to color copper.
For a BLACK coating: crush a lump of liver of sulfur in a glass container of water (use heat proof glass if you plan to warm the solution). Use enough liver of sulfur to give the water a medium-yellow tint (about 1/2 oz of the chemical to 2 quarts of water) and stir to dissolve it. Heat will also help dissolve the chemical, and keeping the bath hot will increase its effectiveness, but it is not necessary.
The solution has a strong odor and is best applied out of doors or with windows opened. Immerse the work and move it about in the solution, or treat small areas with a cloth swab. When the metal appears dark enough remove the work and rinse it with cold, running water, to stop the darkening action, then rinse with hot water. If you wish a darker coloration , repeat the process. For an even effect, wire-brush the copper between applications.
Ordinary vinegar, salt, and sugar mixed together and brushed on copper daily will turn it Chartreuse. Use about 1/2 TBSP each of salt and sugar with 1 quart of vinegar and keep the solution in a glass botte or jar.
A green-turquoise patina solution that is commercially available produces an intense light green on exposed copper if the metal has been thoroughly cleaned. When applied to partially cleaned metal, it produces a dull green or a green-yellow.
The silver-plating solution sold by suppliers, a light application of which may be referred to as a silver wash, will produce a dull-pewter to a brigh-silver effect on clean copper surfaces. When applied to a lightly scrubbed or unclean surace, it will give purples, golds, greens and other colors. This coloraiton is not predictable but its development is often enhanced if a bare copper tile is left overnight on top of the solution-washed copper, or if a thin film of diluted acid is left on after the scopper has bee cleaned and before the silver-plating solution is applied. These effects may be sprayed with lacquer, but test prove that, with minimal handling, they will survive unchanged even when unlacquered.
SURFACE VARIATIONS
SALT GLAZE
Salt should not bde used in an enameling kiln. It may affect the inside of the chamber and future firings. However, a salt glaze can be fired with a torch. Thicker gauges of copper respond to this better than foil does, but propane seldom generates enough heat to fuse the enamel on heavy copper. Acetylene will work on heavy copper, but all safety precautions should be observed when using the gas.
To begin experimenting, apply a thin coat of liquid enamel to a panel of copper (about 20 gauge, B & S). Sprinkle salt irregularly over the enamel. Allow the coat to dry and fire it with the acetylene torch. The effect will be rough-textured and speckled, similar to the potter's salt glaze. Used with various enamels, dry or liquid, salt glaze produces tones of color which can be adaped to vigorous compositions.
Salt glaze can be fired on copper foil with a propane torch. However, the application of heat is hard to control on thin copper, and with too much heat the salt may melt and the speckled appearance may dissolve into a dirty, caramel color.
COPPPER NITRATE GLAZE
Dark green fern-like, radial patterns with a soft texture may be made by dripping a solution of copper nitrate into wet or dry, white liquid enamel. Depending on placement of the chemical, coloration and pattern will fire out unpredictably as distinct circles or as interconnected webbing. Use a solution of water and copper nitrate crystals (approximately 1:1 by volume) dropped from an eyedropper or from a straw used as a pipette.
When the solution is dropped on wet or damp liquid enamel and the work is fired wet, it will create small, black craters. The edges of the craters will bubble and spread in halos of soft blue. The interiors will be a satiny black. This pattern can be overlaid with transparents for subdued colorations.
If the copper nitrate solution is dropped on a dried, liquid enamel surface, keep the application of each drop at least an 1 inch apart. You may also place a tiny crystal of copper nitrate in the center of each drop to increase the pattern's intensity. Let this applied solution dry for at least 24 hours before firing the piece. If the climate is damp, let the work dry outdoors and the copper nitrate will feather and link its borders among the drops and crystals, If you wish to create the interconnected webbing and the weather is dry, spray a fine mist of water on the piece every 4 - 6 hours for at least a day, letting the work dry between each watering and for six hours after the final dampening.
Firing the copper nitrate solution may produce noxious fumes which can cause respiratory illness and nausea. The fumes vary according to the size of the piece and how much copper nitrate is applied. To fire the solution without problems, try to place the kiln out of doors, or at least near an open window. Do not use this techniuqe in an enclosed space. A fan may be placed near the kiln and used to blow the fumes out of the area. During the firing, if the odor becomes strong, unplug the kiln and immediately seek fresh air. Do not inhale the fumes. If you must remove the work from the kiln, do so holding your breath. Do not re-enter the room unti lthe metallic odor has gone.
ACID LUSTERS
Soft enamels, or low-firing enamels especially reds, will take on a rainbow hue when they are fired lightly in the kiln and then submerged in a nitric acid bath (1 part acid to 2-4 parts water). A long exposure will dull the red color. A 2-3 miute bath is long enough to develop an acid luster without hurting the color and cutting the surface of soft enamel. Remove the piece fro the solution, wash it, and neutralize any traces of acid on it in a household-detergent bath. Rinse well and let it air-dry.
After the work is dry, a luster should have formed. If not, repeat the procedure. This rainbow coloration is also an almost certain by-product of acid cleaning a foil inlay that has been fired on enamel. If you wish to remove the luster, refire the inlaid work very lightly and then clean the new firescale on the inlay with vinegar and salt, instead of exposing it to stronger acids.
MAT SURFACES
Special enamels are manufactured which produce a mat or satin-mat surface, and enamels in general use may be dulled with acids, and commercial preparations. Some brilliance may be lost this way, but accents or overall mat textures may become an important design element, both visually and tactually.
The surface glow of soft enamels will be cut by placing them in a mild, nitric acid bath, although prolonged exposure to the acid may make them vulnerable to staining. For work that will not be handled often, this is not important.
As an alternative, undiluted hydrofluoric acid can be swabbed onto the enamel surface, but it must be used with caution; it must be kept in the bottle in which it is sold and must never be put in glass containers, for it eats through glass. Fumes are very toxic and can also damage the surface of eyeglasses worn near them. Skin contact should be treated at once with soap and water or with whiting. Experiments for this book were made outdoors; rubber gloves were used and the acid was applied to the enamel with a tightly rolled swab of cloth tied onto a long stick. The swab was dipped into the bottle of acid and applied to the enamel from a distance. (The enameled copper was placed on a thick layer of newspapers). A layer of broken-down enamel developed in a few moments. Rubbed away with the swab, it showed the mat surface was ready. The work was then picked up with 2 wooden spoons dipped into a plastic dishpan of water nearby and then rinsed under running water. Selected areas of the enamel can be blocked out with resists of etching asphaltum or warm beeswax or paraffin, to preserve their gloss.
There are simpler and less hazardous methods to produce mat surfaces. Enameling suppliers have a mat salt, which is easily applied in a paste form to the enamel. When the paste is washed off, a soft, mat surface appears. There is also a mat enamel which, when applied to fired enamel and fired, will diminish the gloss without changing the color of the enamel underneath.
Another method of obtainig a mat surface is to grind down an enamel with a carborundum stone and water, finish it with emery paper or cloth and finally polish it with powdered pumice mixed to a paste with water. In preparation for painting or brush drawing on the enamel, rubbing the surface with emery cloth gives it a "tooth" that takes the painting medium well. The emery dust should be washed off first. A gloss will return to the surface when the panel is refired to fuse the painted enamel. After this, a mat surface may again be made by any of the methods just described.
PATINAS
A soft blue-green film will gradually develop on copper from chemicals in the atmosphere when the metal is exposed outdoors. If time does not permit waiting for natural patinas, treatment made with metal colorants can give a number of effects. There are many formulas in books on metal-working and solutions are sold commercially by metal and enameling suppliers. Foil inlays and copper exposed by flooding, sgraffito, ripple or cantaloupe skin, lecithin granules, firescale irregularities, and stencils may be colored. A basic rule is that the metal must be very clean for solutions to give specified effects. Following are simple mixtures used to color copper.
For a BLACK coating: crush a lump of liver of sulfur in a glass container of water (use heat proof glass if you plan to warm the solution). Use enough liver of sulfur to give the water a medium-yellow tint (about 1/2 oz of the chemical to 2 quarts of water) and stir to dissolve it. Heat will also help dissolve the chemical, and keeping the bath hot will increase its effectiveness, but it is not necessary.
The solution has a strong odor and is best applied out of doors or with windows opened. Immerse the work and move it about in the solution, or treat small areas with a cloth swab. When the metal appears dark enough remove the work and rinse it with cold, running water, to stop the darkening action, then rinse with hot water. If you wish a darker coloration , repeat the process. For an even effect, wire-brush the copper between applications.
Ordinary vinegar, salt, and sugar mixed together and brushed on copper daily will turn it Chartreuse. Use about 1/2 TBSP each of salt and sugar with 1 quart of vinegar and keep the solution in a glass botte or jar.
A green-turquoise patina solution that is commercially available produces an intense light green on exposed copper if the metal has been thoroughly cleaned. When applied to partially cleaned metal, it produces a dull green or a green-yellow.
The silver-plating solution sold by suppliers, a light application of which may be referred to as a silver wash, will produce a dull-pewter to a brigh-silver effect on clean copper surfaces. When applied to a lightly scrubbed or unclean surace, it will give purples, golds, greens and other colors. This coloraiton is not predictable but its development is often enhanced if a bare copper tile is left overnight on top of the solution-washed copper, or if a thin film of diluted acid is left on after the scopper has bee cleaned and before the silver-plating solution is applied. These effects may be sprayed with lacquer, but test prove that, with minimal handling, they will survive unchanged even when unlacquered.