Coil building techniques (hand building) technique (Italian name Colombino) is a method of creating pottery. It has been used to shape clay into vessels for many thousands of years. It ranges from Africa to Greece and from China to New Mexico. They have used this method in a variety of ways. Using the coiling technique, it is possible to build thicker or taller walled vessels, which may not have been possible using earlier methods. The technique permits control of the walls as they are built up and allows building on top of the walls to make the vessel look bigger and bulge outward or narrow inward with less danger of collapsing. Coil build is the best techiques for realize prototype and sculpture.
Coil building techniques
We start preparing clay coils by hand or with an extruder (bigoli). We prepare first layer of coil pushing each one into the slab.
Score and slip slab and lay the first layer of coil. Push the coil firmly into the slab. Cut first layer of coil as illustrated below to insure perfect fit around the parameters of the slab. Remove the unused coil pieces and blend the joint. Pinch / scrape the coil with one finger into the slab smooth using your finger, a rib or a wooden tool.
Smooth the outside using a different tools. Place the next layer of coil, pinch and smooth and in previous layer. When merging two layers, make sure that one hand is supporting the clay on one side while the other hand pushing / smudging the other side. Keep adding layers. You can add up to three at a time before blending and smoothing. When cutting a coil to fit, make the cut in a different place to insure that two joints are not directly one above the other. To widen the pot, use longer coils. If taking a break cover your work and pre made coils so that the clay will remain moist and soft.
Use the same method as above to create the pot’s rim. You may choose to leave the rim “un-smoothed” as illustrated below. If making a large pot, it might be too soft to hold it’s full weight. Cover it and allow it to set for a while before proceeding. When starting again, the next coil added MUST be slip-and-scored to the existing pot. Use a paddle to both shape the pot and strengthen the coiled wall. Dry slowly by covering the pot loosely with plastic before firing.
Using a simple rolling pin, you push and roller a piece of clay up to a thickness of about 1 cm, taking care to maintain a uniform height over the entire surface. Formed our ‘pizza’, we must make it circular. Placing the piece of clay on a turntable is the wheels and, with any sharp tool, is ‘trim’ the base, creating a circle.
It ranks the first coil edge of our circle and practice a little pressure with the thumb and forefinger, while the other hand supports and guidance. The aim is to ‘weld’ the coil clay along the perimeter. This operation is repeated by placing the coil one on the other in a spiral, up to reach the desired height. Is obtained, thus, the first artifact in clay.
The slab is a type of techniques very common and simple to learn. In the initial phase of work, the forms to be used as ‘holders’ for keeping in shape the clay can be manifold: large bowls but also bottles, balls, tubes.
Place two strips of wood on canvas a little further apart than the width of the finished slabs.
After few times (30 minutes or more) slab are nice consistence (loose humidity) we can work on it, cut or assemble by slip clay (barbottina)
By hand building techniques you can realize infinite ceramic shapes!