Clay is one of the most malleable forming substances known. It is ideal for almost any shape or design. It can be embellished with extremely intricate detail and even combined with other materials Anything from a tiny figurative sculpture, to a massive bowl can be formed in clay. Molds can be used to make clay and can take on any form or texture. Some clay bodies, as in this example, are self-hardening and require no kiln-firing to cure. Self-hardening modelling clay is therefore an ideal starting material that lets you focus on the modelling aspect.
Estimate the amount of clay you will need for your modelling project by using a simple rule of thumb. Keep in mind that 0.454kg. of clay is approximately the size of a tennis ball. A large grapefruit might have the volume of 1.36kg. of clay. Measure the project dimensions you have in mind, and use these examples to gauge the volume and consequently the required amount of clay by weight.
Use supporting structures for clay sculptures that are top-heavy or will not support themselves when the clay is in a wet state. Once the clay has dried and hardened, these supporting structures can be removed. Make sure to construct any supports in a way that you can remove them once the clay can support itself.
Calculate that the clay will shrink as it dries, while your supporting structure does not. Be careful to accommodate for shrinkage so that the static support does not create undue pressure on the clay. Release any pressure by altering or removing the support before it cracks the clay.
Create the basic shape of a model using your hands. Use your finger to create contours and lines where possible. Use water on your hands to create smooth lines without tearing the clay surface. Do not use too much water as it will destabilise the clay. Use tools such as a knife, a needle tool and wooden scrapers to form, detail and add texture to the clay. Improvise with objects you can press into the clay to create unique textures.
Hollow out thick pieces of clay where possible to prevent them from blowing up on the kiln when using other types of clay due to trapped water content. Fill hollow sculptures with crunched-up paper to support the clay as you shape it. Remove the paper before firing or burn it off in the kiln
Keep clay wrapped in plastic bags, as it will dry out and become unusable without extensive recycling procedures. Cover unfinished clay projects when absent to keep it from drying out as well. Remember that clay likes to dry slowly, especially when it is thick.
Finish all the detail work before the clay dries as it will become very brittle in a dry state. Use a wet sponge to wipe away any fingermarks and to give the surface a very smooth finish.
Let the clay model dry completely before firing it in a kiln. Wait several days for thin objects and two to three weeks for very thick pieces.