Inclusions/Infusions

An inclusion or infusion is anything that is mixed into polymer clay to alter its color or texture. Inclusions are most commonly added to translucent or partially translucent clay, but they may be added to any clay, though in opaque clay they will only show on the surface.

Inclusions

Adding very large amounts of any inclusion may weaken the clay. However, most of the time this is not an issue. If you are concerned about the strength of your final product, mix a small batch with the desired proportion of inclusions, cure the clay, and test it for flexibility and durability.

Below is a list of some of the inclusions that can be added to polymer clay:

• Glitter- Glitter comes not only in a rainbow of different colors, but also in a number of sizes (from extra fine to large) and shapes (circles, squares, hearts, stars, moons, etc.). Look for "confetti"-style glitters when making faux opals.
• Sand- Use either natural sand or colored sand. Art sand in a variety of colors is available in craft stores, or you can color your own sand using a drop or two of food coloring.
• Metal Leaf- Though metal leaf is more often used for mokume gane or surface applications, you can also mix leaf into clay until it breaks into tiny bits suspended throughout the clay. Some metal leaf may even be available for sale in flecks, such as the "Metallic Dust" line of products from Arnold Grummer.
• Soil- Just a little earth from your own back yard can produce interesting results.
• Herbs and Spices- Raid your kitchen spice rack and see what you find. Oregano, pepper, paprika-each yield interesting and unique results.
• Dust or Lint- Mix in dust or lint from your clothes dryer's lint-trap until you reach the desired consistency.
• Powders- Mica powders, metal powders/pulvers, embossing powders, powdered chalk, powdered cosmetics-- each produce a different look.
• Crayon shavings- Use a craft-dedicated cheese grater or vegetable peeler to create crumbles or curls of your choice of crayon colors, then incorporate them into the clay.
• Cured clay- As with the crayons, take shavings or crumbs of cured clay and mix them into raw clay. (This is a great way to make use of a failed project, ugly bead, or shavings resulting from clay carving. Or cure a little piece of clay especially for using as an inclusion.)
• Dried flowers and leaves- Make sure that your flowers or leaves are fully dried to avoid excessive plaquing (unless that's your desired result). Mix crumbled flowers or leaves into clay.
• Flour/Semolina- Mix a bit of flour, corn meal, semolina, etc. into raw clay to emulate the texture of baked goods.
• Fibers- Bits of colorful yarn, thread, or embroidery floss, pet hair clippings-- all sorts of man-made or natural fibers can be incorporated into raw polymer clay.
• Tiny beads- Either seed beads or the tiny, holeless glass balls sold as scrapbook embellishments can be mixed into polymer clay.

Infusions

Infusions are also non-clay materials that are mixed into polymer clay, but while inclusions are solids, infusions are liquids (more or less). They work in generally the same way as solid inclusions.

The following are a few infusions that can be used with polymer clay:

• Alcohol ink- Vivid, translucent alcohol inks (such as the Piñata and the Adirondack lines) can add beautiful color to translucent liquid and solid clays. To tint liquid clay, drop a tiny bit of ink on top of the liquid clay. (A little goes a long way, so go slowly.) Let the ink sit for half an hour or so, to allow the alcohol to evaporate, then stir for translucent color. To tint solid raw clay, drop a bit of ink on top of a flattened chunk of clay. Let the ink sit until the alcohol has evaporated, then condition the clay until the color is evenly distributed. (Inks will stain skin, clothing, and carpets, so handle them with care.)
• Paint- Oil paint gives translucent liquid clay opaque color; just mix it right in, a bit at a time. Oil paint can also be mixed into solid raw clay. Small amounts of acrylic paints may also be mixed into solid clay, but because acrylics are water-based, there is always the risk that too much of them can lead to bubbling and plaquing. It's best not to tint liquid clay with acrylics because of this tendency to bubble.
• Scent- You can make your objets d'art smell as pretty as they look by adding scent into the clay. Some solid herbs and spices may smell strongly enough to scent polymer clay, but there are also liquid fragrances that can be mixed into clay. Try essential oils, extracts, and perfume oils.

• Don't limit yourself to the materials listed above. Anytime you see something and think, "Gee, I wonder how that would look in clay?", make a note of it and give it a try!
• Once you've mixed anything with a rough, grainy texture (beads, sand, etc.) into clay, you shouldn't run that clay through your pasta machine, as it can leave permanent dents or scratches on the metal rollers. Instead, flatten the clay with another tool, such as a brayer.
• When working with an unfamiliar inclusion, start small and work your way up a bit at a time. It's always possible to add a little more of the inclusion, if you need it, but it's nearly impossible to remove the inclusion.
• If you find that you've added too much of an inclusion, you can thin it out again by mixing in more clay.
• To keep the mess down when incorporating powders or other small granules into clay, make a dent in some conditioned clay, pour the powders into the dent, close the clay over the powders, and work the clay until the powders are evenly distributed. You can also run the clay through the pasta machine with the inclusions sandwiched between two pieces of clay. Just remember not to put anything too hard through the pasta machine.
• Inclusions aren't just for solid clay. Liquid clay can also be tinted with a variety of powders and glitters.

Links

For more information about inclusions, visit the following websites:

Glass Attic: Inclusions
Compiled by Diane Black
http://www.glassattic.com/polymer/MainPages/inclusions.htm

Altering Polymer Clay with Inclusions
By Lindly Haunani
http://www.lindlyhaunani.com/tips/inclusions.html

Sculpey Clay Projects: Polymer Clay Inclusions
By Kris Richards
http://www.sculpey.com/Projects/projects_ClayInclusions.htm