| Layered Glaze Effects |
| Layered Glaze Effects |
From "Throwing Clay"
episode DTHC-103 |
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Master potter Bill Van Gilder is in the process of making a dip warmer/cooler. Now the components are ready for an application of glaze.
So far, he has thrown a cylinder for the base and a bowl with a flat rim for the top, both 6-1/2" wide. When the pieces were leather hard, he trimmed the rim of the bowl to make it fit perfectly, in this case slightly loose, in the cylinder. He added two textured handles to the cylinder, and when the pieces were bone dry, he fired them in a bisque kiln. Now they are ready to glaze (figure A).1. First, wax is applied anywhere the two pieces meet and on the base. The wax will resist the glaze; otherwise, anywhere glazed pieces touch, they would stick together during the firing process. For ease of application, Bill uses the cylinder as a holder for the bowl (figure B). He waxes under the rim and approximately 1/2" down the bowl's side, applying the wax in a straight, even line (figure C).
2. Next, he waxes the rim of the bowl, after making sure not to overload the brush with wax, which could run down the side of the pot (figure D).3. Bill inverts the bowl on a cylinder to wax the bottom, taking his time to be sure the base is completely covered with wax (figure E); then he sets it aside to dry for about five minute. 4. When the wax is dry, it's time to glaze the pieces. Bill can't dip the bowl in the glaze and set it on the table because it will mar the bottom of the bowl, which isn't waxed. Instead, he dips the bowl and sets it into the base cylinder. Where his fingers have held the rim, he patches the spots with a fingertip dipped in the glaze (figure F).
5. The glaze will dry in 30 to 40 seconds. When it's dry, Bill lifts the bowl out of the cylinder, uses a damp sponge to wipe away any glaze drops on the waxed areas, then re- dips the pot and touches up any bare spots. If glaze has to be cleaned off of waxed areas, it must be done carefully, to prevent accidentally removing glaze from the rim. Since mistakes and crooked wax lines will show up when the pots are fired, Bill has cut a sponge in a pointed shape to fit in the waxed areas beneath the rim (figure G).6. Next, the cylinder is redipped in green glaze. Layering glazes increases a potter's color palette, but the process is as much an art as a technique. The pot is dipped from the top halfway down the side. This dip is always done quickly to prevent glaze build-up, which could make the pot prone to chipping during use. After dipping, Bill cleans the rim and lets the glaze dry (figure H).
7. The pieces are fired nested together (figure I). The weight of the bowl ensures that the cylinder rim stays perfectly round. As Bill loads the kiln for the high-temperature firing, he makes sure no glazed parts touch. Since the underside of the bowl's rim and the rim of the cylinder aren't glazed, he can fire the two pieces nested together without worrying that they will fuse together.8. Over the next 10 to 12 hours, the kiln will heat up to 2,200 degrees. After firing, it cools for at least 24 hours before it can be unloaded (figure J). When the bowl and cylinder are removed, they are often wedged together, so Bill lightly taps the cylinder base to loosen the pieces (figure K). The dip warmer/cooler is now ready to use.
RESOURCES :
Kilns
L & L Kilns
Website: www.hotkilns.com
Clay
Highwater Clays
Website: www.highwaterclays.com
Extruders
American Art Clay Co. Inc. (AMACO)
Website: www.amaco.com
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