What is Polymer Clay?

By: Clay Princess

Polymer Clay is a sculptable material based on the material polymer polyvinyl chloride (PVC). It generally doesn't contain any clay at all and is only called "clay" because it's texture and working properties resemble those of mineral clay.

 

History

Polymer Clay is based on a plastic modeling compound brought to the attention of German doll maker Kathe Kruse in the late 1930's as a possible replacement for plastics that had become difficult to obtain during the early days of World War II. It was not suitable for use in her doll factory, so Kruse turned it over to her daughter Maureen, who was known in the family as "Fifi". The formulation was later sold to Eberhardt Faber and marketed under the name "FIMO" (FIfi's MOdeling Compound) in honor of Maureen.

 

The history of polymer clay as an art medium is only decades long, unlike many media that have been around for centuries and have long traditions. This newness means that there is a great deal of innovation by users of polymer clay. Often, ideas are born by borrowing from the traditions of some other materials, such as metalworking (mokume-gane), ceramics, glass (millefiori, lampwork), paper, etc.

 

Brand Differences

 

Each brand of polymer clay has inherent characteristics that make it most suitable for certain applications. For instance, the more resistant brands hold their shape well in detailed cane work, but they can be more difficult to condition. Some easy-to-condition clays become brittle after baking. Most brands feature a translucent color in their palette, but some brands are more translucent than others, making them more desirable when mixing tiny inclusions (such as glitter) into the clay or layering thin sheets or slices. Some clays change color after baking, making exact color matching more challenging.

 

• Premo! Sculpey is easy to condition and is also strong and flexible after baking. It has a tendency to become quite soft after repeated manipulation.
• Fimo Classic is more difficult to condition than Fimo Soft but is also great for caning. It holds detail well and is very strong after baking, but without much flexibility.
• Fimo Soft is easier to condition than the classic variety but it is not as strong and durable after baking.
• Along with the major catagries listed above, many specialist "clays" have been added, such as Sculpey's Glow in the Dark, Bake and Bend, Eraser Clay and specialised doll making clays.

 

Properties

 

Original formulations of polymer clay remain soft until cured at relatively low temperatures, but air-dry polymer clays have recently been added to the market. Traditional polymer clay hardens by curing at temperatures created in a typical home oven (generally at 265 to 275 °F (129 to 135 °C), for 15 minutes per 1/4" (6 mm) of thickness), and does not shrink or change texture during the process. When properly conditioned and cured, most clays create items that will not break if dropped or normally stressed. Cured pieces may have additional layers or enhancements added and be re-cured with no ill effect. As long as the maximum curing temperature is not exceeded, there is no limit to the number of times a piece can be re-cured. After it has cured, the clay surface can be left as is, sanded and buffed, or finished with a water-based varnish.

 

Leading brands of polymer clay include Fimo; Sculpey and Premo, created by Polyform Products; Cernit; Formello; Modello; and Kato Polyclay, formulated for Van Aken by Donna Kato, an early artist for Fimo. Though the brands differ slightly in properties such as plasticity, translucence, curing temperature, and flexibility when cured, most are suited to a variety of applications. Specialty formulations include clay that remains permanently flexible when cured, eraser clay, and colorless and tinted liquid "clays" that can be used as slips, glazes, and adhesives.

 

Polymer clay is available in many colors. "Special-effect" colors such as translucent, fluorescent, glow-in-the-dark, mica-containing "pearls" and "metallics," and variegated "stone" colors containing contrasting fibers are also available. Standard colors, which vary from brand to brand, can be mixed to create a virtually infinite range of custom colors, gradient blends, and other effects. Judith Skinner[2] is credited with inventing a technique that uses a pasta machine to create consistent gradient-blended sheets of color. This technique has many applications and is one of the basic skills developed by hobbyists or artists in the medium.

 

Polymer clay can be colored with other media. Paint, ink, colored pencil, chalk, metallic or mica-containing powder, metal leaf and foil, glitter, and embossing powder can be applied to the surface. The same materials also can be mixed in as inclusions; this is often done with translucent clay. When acrylic paint is cured onto the surface, it forms a permanent bond with the surface.

 

Few tools are essential for use with polymer clay, and these can often be found around the house. The most widely used cutting tools are tissue blades, which are extremely thin and sharp, though craft knives and other blades can be used. A pasta machine is often used to create sheets of uniform thickness, to mix colors, to condition the clay, and to create patterned sheets. A "clay gun" or extruder with interchangeable die plates allows creation of lengths of clay in a variety of uniform sizes and shapes. Most molding and modeling tools used by traditional sculptors are suitable for polymer clay, but artists often create improvised cutting, piercing, molding, and texturing tools from items used in sewing, cooking, woodworking, and paper crafts.

 

Uses and Techniques

 

Polymer clay can be used in many ways, a number of which have been generalized from other art or craft techniques. Some uses for polymer clay include:

 

• Sculpting. Hand-shaped items can be any size from "miniatures" to quite large. Bas relief can also be created; clay clothing and accessories can be made for sculpted figures.
• Creating beads and jewelry of all kinds, such as pendants, earrings, barrettes, and buttons.
• "Cover"ing items made from materials such as glass, metal, cardboard, terra cotta, and some plastics. Popular items for covering include pens, eggshells, votive candle-holders, and switch-plates. Larger items, such as tables, can also be veneered.
• Creating vessels large and small. Jars, boxes, bowls, and container pendants can be created freestanding, or over permanent or removable armatures.
• Creating simulations or fauxs of many natural and fabricated materials such as jade, turquoise, marble, granite, metal, ivory, wood, leather, stained glass, mosaic, and cloisonne.
• Onlaying clay or other materials to create collages. A "clay gun" can be used to extrude uniform rope shapes.
• Creating paintings with polymer pastes, and bas reliefs.
• Creating practical utility items, such as frames, games and game pieces, dioramas, toys, mini-books, notebook covers, greeting cards, and postcards.

 

Techniques for working with polymer clay include:

 

• Gradient (Skinner) blending of two or more colors using sheets of clay and a pasta machine or rolling pin.
• Forming "canes," which are logs of clay with patterns running through their entire length, from which identical slices can be cut and used in various ways. The patterns created in canes can be simple, complex, or anything in between; they may be pictorial or simply geometric. Canes (and therefore their images) can be "reduced" so that they become quite small, and then combined to make multiple images (millefiori).
• Impressing textures, lines or images into raw clay with rubber stamps, texture sheets, sandpaper, needle tools, or other items.
• Molding: pressing raw clay into molds to create casts and to duplicate textures, shapes, etc. Molds made from metal, glass, rubber, and silicone can be purchased, or custom molds can be made from polymer clay or dedicated molding compounds.
• Extruding clay through shaped die plates to create strands or ropes of uniform size and cross-section.
• "Mokume-gane": thin slices shaved from distorted stacks of layered clays, powders, and inks and applied to surfaces.
• Using clay to accept "transfers" of images from photographs, drawings, computer-created images or text using a gin transfer or transfer paper.
• Images can also be transferred onto freestanding liquid clay films or decals.
• Carving or drilling after the clay has been cured (and backfilled, if desired).
• Inlaying cured or uncured clay tiles or chips to create mosaics.
• Multimedia: combining clay with wire, paper, beads, charms, stamps, fabric, etc.