For a clever and creative visual artist, pretty much any type of object or material can be a medium for fine sculpture art. This includes cardboard, though the use of cardboard for three-dimensional models requires some special handling. This flat, lightweight material can be transformed into some stunning models if you take proper care to give it dimension, shape and, if necessary, some strengthening reinforcement.
Layering in cardboard sculpting is a method of rendering three-dimensional shapes and textures using a stack of flat sheets that get progressively smaller. For example, to create a dome shape, the artist would start with a circle and glue a series of smaller and smaller circles on top of it, all centred. Since the layers are visually apparent, this technique creates a stylised dimensional texture, but one that will give the finished piece a more solid construction.
Moulding is used to shape a piece of flat cardboard into one with a raised curve. This effect it easiest to achieve with corrugated cardboard, which naturally has some stretch and give when you bend and shape it with your hands. This process makes it soft and floppy, however, so it must then be reinforced with glue or steamed. You can also use steaming to shape noncorrugated cardboard; soften it with heat and moisture until it's soft and floppy, then lay it over a hard, nonporous surface and let it dry in the proper shape. This effect is used to create bowl-like shapes or other rounded surfaces in a sculpture.
When creating a portion of a sculpture made from a single tall and thin sheet of cardboard, sometimes you'll need to stiffen it to give it added strength. This is particularly important if other structures are attached to the top of the thin, standing portion. To thicken, soak the cardboard in water and wood glue, découpage medium or a wood-hardening liquid. This is particularly effective with corrugated cardboard, which is especially absorbent and will become quite strong with this treatment.
Since cardboard recycling is often used as a means of up-cycling cardboard scraps, it's useful for an artist to find ways of working with small strips of cardboard, even in larger sculptures. With a simple over-and-under square weaving, you can turn a lot of long, thin strips of corrugated cardboard or flexible paperboard into a large, flat sheet. Weaving also creates a more flexible, fabric-like texture, one that's more supple the smaller the strips of cardboard you use.