The Three Techniques of Making Hollow Forms in Clay

Jewely makers use hollow forms to create beads and other hollow objects.

Clay hollow forms are used to make metal clay jewelry and sculpture. These templates allow the artist to make larger beads and other objects that she would otherwise be able to, because the empty interior keeps the weight of the piece and the cost of materials down. There are several techniques for making hollow forms in clay, using different filling substances and covering clays. Whatever material fills the hollow portion of the form must be solid enough to maintain its shape during the process, but burn away or otherwise be removed later on.

Cork Clay

Available from metal clay specialty suppliers, cork clay is a versatile and popular option for making hollow forms. Cork clay holds the shape of the bead of other object very well and dries to a lightweight substance. Cork clay will burn away entirely during firing, but it is one of several hollow form substances that emit toxic fumes when burned. Use the cork clay technique for making hollow forms only if you have a kiln in a well-ventilated area. Keep the door closed during firing. Fire cork clay hollow forms at 1,472 degrees Fahrenheit, no higher. Cork clay becomes very hot when it is burning and the exterior material may be damaged at higher temperatures.

Creative Paperclay

Creative paperclay, made of volcanic ash, is another material that is used for making hollow forms in clay. Creative paperclay does not burn away in firing, making it optimum for projects that you do not want to see shrink very much during firing. When using paperclay to make your hollow forms, make sure the holes in your bead or other object are very large so that you can easily chip out the paperclay after firing. Drinking straws are a good choice for making large enough holes in the hollow form.

Lump Clay

Paste clay and lump clay are two options for creating the outside of your hollow form. Once the core has been made to the desired shape, it needs to be covered with your finishing surface. Lump clay is rolled out into a thin slab, less than a centimeter, and wrapped around the form. Using tools and fingers, work the lump clay to the proper shape, following your hollow form's core material. Many projects, such as beads, will use lump clay only.

Paste Clay

As an alternative to lump clay, paste clay can used to cover hollow forms. Paste clay is optimum if a piece has complex shapes. Paste clay is applied in thin layers with a brush. Each layer must dry completely before the next one can be applied. Paste clay is excellent for small sculptures and more intricate hollow forms.

References

• The Art of Metal Clay: Techniques for Creating Jewelry and Decorative Objects, 2003, by Sherri Haab (via Googlebooks)
• Metal Clay Jewelry, 2006, by Louise Duhamel (via Googlebooks)