Modelling clay

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A bust of the sculptor Albert-Ernest Carrier-Belleuse, by Auguste Rodin (1882). Terracotta, originally modelled in clay.
Giant clay sculptures in Caruaru (Brazil).
Roses and seashells made of Paperclay (DECO)
An artist modelling a bust of Confucius in clay
Industrial clay: a clay model of a BMW

Modelling clay is a group of malleable substances used in building and sculpting. The material compositions and production processes vary considerably.[1]

Ceramic clay[edit]

Ceramic clays are water-based substances made from clay minerals mixed with other raw materials. They are baked at high temperatures, in a process known as firing to create ceramics, such as terra cotta, earthenware, stoneware, and porcelain. Paper clay produced by pottery clay manufacturers is any of these clay bodies, to which a small percentage of processed cellulose fiber has been added. When kiln fired, the paper burns out, leaving the clay body. Consequently the firing temperatures and glazes selection should be the same on those used with the clay body.

Oil-based clay[edit]

Oil-based clays are made from various combinations of oils, waxes, and clay minerals. Because the oils do not evaporate as does water, oil-based clays remain malleable even when left for long periods in dry environments. Articles made from oil-based clays cannot be fired, and therefore are not ceramics. Because the viscosity of oils decreases as temperature rises, the malleability is influenced by heating or cooling the clay. Oil-based clay is not soluble in water. It can be re-used and so is a popular material for animation artists who need to bend and move their models. It is available in a multitude of colours and is non-toxic.

Oil-based clays are referred to by a number of genericized trademarks. Plastilin, was patented in Germany by Franz Kolb in 1880. Plasteline was developed by Claude Chavant in 1892, and trademarked in 1927.[2] Plasticine was invented in 1897 by William Harbutt of Bathampton, England. Plastilina is trademarked as Roma Plastilina by Sculpture House, Inc. According to their website, their formula is 100 years old.[3] Roma Plastilina contains sulfur, and since certain moldmaking compounds will not set in sulfur's presence, this brings difficulty to making molds of items made of it Industrial plasticine.

"Peacock" modelling clay is available and widely used by sculptors and animation artists in India. This does not contain sulphur and is non-toxic.

Being readily worked in fine detail, oil-based clays are also suitable for the creation of detailed sculptures from which a mold can be made. Castings and reproductions in a much more durable material can then be produced. Cars and airplanes may be created using industrial design-grade modeling clay.

Polymer clay[edit]

Polymer clay is a modeling material that cures when heated from 265 °F (129 °C) to 275 °F (135 °C) for 15 minutes per 14 inch (6.4 mm) of thickness, and does not significantly shrink or change shape during the process. Despite being called "clay", it generally contains no clay minerals. Polymer clay is sold in craft, hobby and art stores, and is used by artists, hobbyists, and children. Polymer clay is also popular in animation since it allows static forms to be manipulated frame after frame. Leading brands of polymer clay include Fimo, Kato Polyclay, Sculpey, & Modello.

Paperclay[edit]

There are two major groups of paper clay/paperclay users: those using paperclay as an unfired body predominately for recreational use or doll making, and those using paper clay in the ceramic art studio to make sculptural and functional studio pottery.

Commercial air drying paperclay does not shrink noticeably when drying. Paperclays are cellulose based substances which air dry firm. The finished sculpture is extremely lightweight.

Paper clay is hand made or commercially available clay to which a small percentage of processed cellulose fibre is added, to increase the tensile strength of dry clay, enable dry to dry and soft (wet) to dry joins.[4]

See also[edit]

References[edit]

  1. ^ Putman, Brenda, ‘’The Sculptor’s Way: A Guide to Modelling and Sculpture’’, Farrar & Rinehart, Inc, New York, 1939 p.8
  2. ^ http://www.sculpturetools.com/chavant/cart/plasteline.html
  3. ^ http://www.sculpturehouse.com/about_us.aspx
  4. ^ ""A Paperclay Update" by Graham Hay". Ceramics Technical. 2006. Retrieved 2007-12-14.  Article hosted by grahamhay.com.au