Updated: Dec 5, 2020
For the most part, you can treat paper-clay just like regular clay, but it does handle a little differently. It is a little harder to “move” the clay. If you do a lot of carving, the paper pulp can interfere with clean, precise carving. It feels different and takes some getting used to. Most significantly: It molds after a period of time. The period of time varies from 1 week for paper-clay made with toilet paper to 2-4 months for commercially made paper clay.
Here are some techniques to handle these and other differences:
Use very sharp knives (Exacto-type) instead of usual dull fettling knife.
Wet and score the existing clay very well when adding wet to dry or repairing with paper-clay slip. Add paperclay slip to help the transition. This helps to “meld” the paper fibers from the new clay into the dry existing structure.
Firing: Remember that paper will burn out, and thin clay that is left is more subject to warping, cracking and breaking than thicker regular clay. Some people report fumes during firing. I have not found fumes to be a problem above about 600 degrees.
Paper clay still cracks and warps...just not as much as regular clay.
Fired qualities and most of working qualities depend on base clay body to which paper is added. Firing temperature is extended somewhat because of porosity up to a certain point. At lower temperatures (below cone 6) the clay is stronger when fired. At higher temperatures and with porcelain, the clay body will slump and/or crack and tend to be over fired. Thin pieces fired at or near vitrification will still crack, warp or break.
Paper clays dry more evenly...may appear to not be drying....then all of a sudden, it is dry!
If you like to carve clay, you may find it more difficult because of the paper fibers. One way around this is to fire to 400 degrees Fahrenheit and then it carves more easily (but is somewhat fragile at that temperature).
To avoid mold and rot of paper, use mixed up paper clay quickly or store as dry slabs and then re-wet when ready to use. If it does mold, just dry out and then re-mix into a slip. Add some cleaner, like 409, or mold guard used in humidifiers, to the slip when making or re-constituting paper clay. Avoid Clorox as it will tend to break down the paper. I use pure cotton linter (which you can buy from the art-supply store) to reduce the mold factor.
Mix some paper clay with magic water as super mending slip. Magic water is made with 3 tablespoons liquid sodium silicate and 1.5 teaspoons dry soda ash per gallon of water.
New Clay Methods using Paperclay
Here are some ideas for new ways to work with paper clay that are different from traditional clay working methods.
Dry Slab method. Work with dry slabs, joining them with paperclay slip and magic water. Take advantage of the strength of dry paper clay and preserve the texture applied to the slabs. Slabs can be pre-formed as flat, curved, or any shape. You can use tools and techniques similar to wood working or paper sculpture on the dry slabs.
Dry framework method. Make a sculptural “skeleton” shape and let it dry. Then, add paper-clay “skin” over the top and finish in whatever surface look you like. This method allows you to build a larger, more radical shape. Use pieces of metal as the framework...found or welded. Some cracking of clay around framework can be expected, especially around metal.
Add other inorganic materials, such as pieces of metals, rocks, dirt, dry glazes, fired clay pieces. These can be added as layers to slip, casting into forms, and then saw them up. Can build clay around metal “hardware cloth” or wire. Clay will crack and pull around metal, but not as much as regular clay. Variations in materials when firing will produce interesting ‘layers” or texture effects. The bond between clay and paper may be broken somewhat by these materials if they are well-mixed into the clay (like grog), so the green-strength may be reduced.
Add inorganic materials, such as straw, wood, weeds, pet litter or food, corn cobs, etc. These will burn out in the firing, if you fire the pieces, and make an interesting texture.
Dip string, rope, fabric, or other objects into the paper clay slip and build with them. You may need to dip or brush 3 or more coats on the material to make a thick enough coat to hold up in firing.
Put paper-clay slip thin on flat plaster surface to make slab. When dry enough, roll, cut, etc. to make form.
Don’t fire...build the piece in any kind of method, including solid, and let it dry. Finish with any number of “cold” surfacing techniques to seal.
See other posts for additional information about paperclay. Here is the full handout as a pdf: