Published Dec 9, 2013
The intricate and vibrant surfaces of Liz Quackenbush's work are mesmerizing. They are also the result of many layers and firings.
In today's post Liz shares how she creates these incredible surfaces as well as the recipes for her low-fire clay body, glazes and overglazes. –Jennifer Poellot Harnetty, editor
P.S. You can learn more about Liz's work (and see more images) in the article by Glen R. Brown in the January 2014 issue of Ceramics Monthly.
I apply all of my glazes to bisque ware with a brush. They need to be painted on in very liquid strokes, never allowing the brush to dry out during application. To avoid thin spots, which can resemble spilled milk after the firing, the glaze must be applied in a number of coats that, together, are the even thickness of a dime or a little thicker. I test this thickness by pushing my fingernail through the glaze to the clay body. Another way to avoid the look of a thin glaze coat is to apply a coat of white slip to the leather-hard clay wherever you plan to glaze.
After the glaze is applied, let it dry on the pot and then gently rub the surface with your fingertip and, while wearing a dust mask, and working outside or in a ventilated spray booth, use compressed air to blow off the dust. Rubbing the glaze surface helps to break up any air bubbles and decreases the potential for pin-holing.
Once the glaze is applied and rubbed down, it is ready for you to paint on. I start by planning out my decoration in pencil—the pencil lines will burn out during the glaze firing. Once the design is laid out, I start to paint using coloring oxides and stains mixed with Gerstley borate.
After the glaze firing, I apply the lusters using a clean brush that’s dedicated to luster use. The fumes given off by the luster are very dangerous so you should always wear rubber gloves and an appropriate vapor mask (or properly fitted respirator) and work in a well-ventilated area when using them. If the luster gets too thick to brush on smoothly, thin it with a drop of turpentine. To clean your brushes, use turpentine, followed by soap and water. Fire the luster decoration to cone 017 in a well-ventilated kiln.
Lastly, I add vivid color using fired on glass enamels made by Reusche (www.reuscheco.com). Most colors can be painted on in one layer, but some get muddy unless they are painted on in many thin layers with a firing in between each layer. This process
can take time, but multiple firings can achieve vibrant colors. Slowly layering materials and imagery also allows the piece to evolve organically.
Overglaze colors (Cone 04)
I use cobalt carbonate for blue, copper carbonate for green, manganese dioxide for brown, and green chrome oxide for a forest green. These colors are mixed with water and painted on top of the white maiolica base glaze. Other colors can be achieved by using Mason or Degussa stains. They should be mixed with Gerstley borate in a ratio of 1 part stain to 3–4 parts Gerstley borate (by volume). If a color appears dry after firing, add more Gerstley borate to help melt the color.
Glass Enamels (Cone 021)
www.reuscheco.com) glass enamels come in many colors. They are powders and need to be mixed with a medium before use. For the medium, I use a mixture of 1 part antifreeze with 3 parts water (by volume). I scoop a spoonful of the powdered enamel on to a pane of glass, add a small amount of medium, and mash it with a pallet knife until it forms an evenly thick paste.Reusche brand (
At this point, I put the medium away and only add water if needed. Even if it drys out, I only add water to moisten this mixture after the original paste is made. The enamels are painted on to the glaze-fired surface and fired to cone 021.